NASA Technical Memorandum 104566, Vol. 16

SeaWiFS Technical Report Series

Stanford B. Hooker and

Elaine R. Firestone, Editors

Volume 16, The Second SeaWiFS Intercalibration

Round-Robin Experiment, SIRREX, June 1993

James L. Mueller, B. Carol Johnson, Christopher L. Cromer, John W. Cooper

James T. McLean, Stanford B. Hooker, and Todd L. Westphal

May 1994
NASA Technical Memorandum 104566, Vol. 16

SeaWiFS Technical Report Series

Stanford B. Hooker, Editor

NASA Goddard Space Flight Center

Greenbelt, Maryland

Elaine R. Firestone, Technical Editor

General Sciences Corporation

Laurel, Maryland

Volume 16, The Second SeaWiFS Intercalibration

Round-Robin Experiment, SIRREX, June 1993

James L. Mueller

CHORS/San Diego State University

San Diego, California

B. Carol Johnson and Christopher L. Cromer

National Institute of Standards and Technology

Gaithersburg, Maryland

John W. Cooper

Hughes STX

Lanham, Maryland

James T. McLean and Stanford B. Hooker

NASA Goddard Space Flight Center

Greenbelt, Maryland

Todd L. Westphal

General Sciences Corporation

Laurel, Maryland

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

1994
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Abstract

This report presents the results of the second Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Intercalibration

Round-Robin Experiment (SIRREX-2), which was held at the Center for Hydro-Optics and Remote Sensing

(CHORS) at San Diego State University (SDSU) on 14–25 June 1993. SeaWiFS is an ocean color radiometer

that is scheduled for launch in 1994. The SIRREXs are part of the SeaWiFS Calibration and Validation Program that includes the National Aeronautics and Space Administration’s (NASA) Goddard Space Flight Center

(GSFC), CHORS, the National Institute of Standards and Technology (NIST), and several other laboratories.

GSFC maintains the radiometric scales (spectral radiance and irradiance) for the SeaWiFS program using spectral irradiance standard lamps, which are calibrated by NIST. The purpose of each SIRREX is to assure that

the radiometric scales which are realized by the laboratories who participate in the SeaWiFS Calibration and

Validation Program are correct; that is, the uncertainties of the radiometric scales are such that measurements

of normalized water-leaving radiance using oceanographic radiometers have uncertainties of 5%. SIRREX-1

demonstrated, from the internal consistency of the results, that the program goals would not be met without

improvements to the instrumentation. The results of SIRREX-2 demonstrate that spectral irradiance scales

realized using the GSFC standard irradiance lamp (F269) are consistent with the program goals, as the uncertainty of these measurements is assessed to be about 1%. However, this is not true for the spectral radiance

scales, where again the internal consistency of the results is used to assess the uncertainty. This is attributed

to inadequate performance and characterization of the instrumentation. For example, spatial non-uniformities,

spectral features, and sensitivity to illumination configuration were observed in some of the integrating sphere

sources. The results of SIRREX-2 clearly indicate the direction for future work, with the main emphasis on

instrument characterization and the assessment of the measurement uncertainties so that the results may be

stated in a more definitive manner.

1. INTRODUCTION

The Sea-viewing Wide Field-of-view Sensor (SeaWiFS)

ocean color radiometer is scheduled to be launched in 1994

and operated in a sun synchronous orbit for five years. The

National Aeronautics and Space Administration (NASA)

will carry out a program to acquire the global SeaWiFS

data set, validate and monitor its accuracy and quality,

process the radiometric data into geophysical units, and

distribute it to the scientific community in the United

States and abroad. The SeaWiFS data products figure as

a prominent component of major scientific programs, including the Joint Global Ocean Flux Study (JGOFS) and

Global Ecosystem (GLOBEC) programs, aimed at improving our understanding of global change.

Two important goals of NASA’s SeaWiFS program are

to determine, from the SeaWiFS radiance measurements,

1) normalized water-leaving radiance with an uncertainty

of 5%, and 2) chlorophyll a concentration with an uncertainty of 30%. All uncertainties are expressed as standard

deviations, σ, unless otherwise noted. These goals are very

ambitious, and can only be achieved by augmenting the

SeaWiFS measurements with a program of ongoing validation measurements to verify the radiometric uncertainty

and long-term stability of the SeaWiFS instrument’s radiance responsivities, and to validate the atmospheric correction models and algorithms used to convert SeaWiFS

radiances to normalized waterleaving radiances. One of

the principal approaches to this critical aspect of validation will be frequent direct comparisons between SeaWiFS

estimates and in situ measurements of water-leaving radiance. Because the primary goal is to demonstrate that

normalized water-leaving radiances derived from SeaWiFS

data have uncertainties of less than 5%, the comparative

in situ radiometric measurements must be calibrated to an

uncertainty less than 5%.

The only economically feasible approach to acquiring

a large and globally distributed sample of in situ radiometric measurements for SeaWiFS validation, is to solicit

contributions of data from the oceanographic community

at large, and to somehow provide assurance that the aggregate data set will be of uniform quality and have an

uncertainty less than 5% (or at least be internally consistent to that level). The SeaWiFS Project at NASA’s

Goddard Space Flight Center (GSFC) is addressing this

problem through the SeaWiFS Calibration and Validation

Program (McClain et al. 1992). At the outset, the Project

sponsored a workshop to draft protocols for ocean optics measurements to support SeaWiFS validation (Mueller

and Austin 1992), which include instrument performance

specifications, and requirements for instrument characterization and calibration.

Of the oceanographers and institutions expected to contribute ocean radiometric measurements to the SeaWiFS

validation database, only a few are equipped to calibrate

and characterize radiometric instruments. Laboratories

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

which currently engage in at least some aspects of the characterization and calibration of oceanographic radiometers

include GSFC; the Center for Hydro-Optics and Remote

Sensing (CHORS) at San Diego State University (SDSU);

the University of Miami (UM); the University of California

at Santa Barbara (UCSB); the University of Arizona (UA);

the Moss Landing Marine Laboratory (MLML) in collaboration with Dennis Clark of the National Oceanic and Atmospheric Administration (NOAA); and several manufacturers of instruments including Biospherical Instruments,

Inc. (BSI) in San Diego, California, and Satlantic, Inc. in

Halifax, Nova Scotia, Canada. The SeaWiFS instrument

is being characterized and calibrated by its manufacturer,

the Hughes Santa Barbara Research Corporation (SBRC).

The strategy adopted for SeaWiFS validation is to calibrate all involved instruments within the network consisting of these, and possibly a few additional laboratories. In recognition of the need to maintain internal consistency between calibrations of in situ instruments and that

of the SeaWiFS instrument itself, the SeaWiFS Project,

under the Calibration and Validation Program, has implemented an ongoing series of SeaWiFS Intercalibration

Round-Robin Experiments (SIRREXs). The purpose of

this program to transfer the National Institute of Standards and Technology (NIST) scales of spectral irradiance

and radiance, through GSFC, to all participating laboratories in the SeaWiFS ocean community, and to the calibration standards used to calibrate the SeaWiFS instrument

for radiance responsivity.

The specific objectives of the SIRREX series are to:

1. intercalibrate FEL lamp working standards of

spectral irradiance used at the participating laboratories, and to reference each to the NIST

scale of spectral irradiance by way of a secondary

standard (FEL lamp F269) to be maintained at

GSFC;

2. intercalibrate integrating sphere sources of spectral radiance used at the various laboratories;

3. intercompare plaques used to transfer the scale

of spectral irradiance from an FEL lamp to a

scale of spectral radiance; and

4. intercompare transfer radiometers and other

support electronics, most critically shunts and

voltmeters, used to support radiometric calibrations at each laboratory.

The first SIRREX was held at CHORS in San Diego,

California on 27–31 July 1992, the results of which were

presented in Mueller (1993). This work demonstrated that

the NIST scales of spectral irradiance were not transferred

from FEL lamp F269 to the 17 other lamps with an uncertainty of near 1%. An uncertainty of 1% is expected,

based on the uncertainty in the NIST scale of spectral irradiance, and general experience with the process of transferring spectral irradiance scales using monochromators.

(Refer to Walker et al. 1987, however, note that Walker’s

uncertainties correspond to three σ values.) Experience

was gained at SIRREX-1 in the methods of comparing the

spectral radiance scales of sphere and plaque sources, as

well as the voltmeters and resistors that are used to determine lamp operating currents.

The Second Round-Robin Intercalibration Experiment

(SIRREX-2), was held at CHORS on 14–25 June 1993.

Conventions used for names, formats, and headers in the

data files comprising the SIRREX-2 data set will be given

in Volume 20 of the SeaWiFS Technical Report Series. Appendix A (in this document) lists the organizations involved with SIRREX-2, along with the point(s) of contact; the instruments tested and measured; and the diameters and areas of these instruments—the dimensions

of which are given in both the International System of

Units (SI), or Syst`eme International d’ Unit`es, and inches.

The participants in SIRREX-2 are listed in Appendix B.

Appendix C gives the results of uniformity studies of the

GSFC sphere performed after SIRREX-2. This report documents SIRREX-2 results for:

a. Lamps: The transfer of the spectral irradiance scale

of FEL lamp F269 to lamps belonging to participating laboratories, is accomplished by using an Optronics 746† spectroradiometer with an integrating sphere

irradiance collector (ISIC), which is referred to as the

746/ISIC.

b. Spheres: The transfer of the spectral irradiance

scale of FEL lamp F269, using the 746/ISIC, to determine the scales of spectral reflectance of the GSFC,

BSI, CHORS, UCSB, and the GSFC Wallops Flight

Facility (WFF) integrating spheres. The secondary

transfer is also reported, using a commercial Photo Research (PR) 714 SpectraScan spectroradiometer (provided by NIST), of the spectral radiance scale of the

GSFC

sphere to the other above mentioned spheres and to the

NOAA Optronics 420M sphere. (See Appendix A for

information regarding diameters of these spheres.) Radiance measurements with the BSI 6-channel transfer

radiometer (BSIXR) are also reported for each sphere.

Radiance measurements of each sphere with the SeaWiFS Transfer Radiometer (SXR) were analyzed. In

addition, radiance measurements of some spheres were

made with the Satlantic 7-channel transfer radiometer (OCR100), for which the data were analyzed by

S. McLean of Satlantic. Radiance measurements made

with the UA Transfer Radiometer (UAXR) are also being analyzed by S. Biggar at UA, however, results from

that instrument are not available for this report.

† Identification of commercial equipment to specify adequately

the experimental problem, does not imply recommendation

or endorsement by the National Institute of Standards and

Technology, nor does it imply that the equipment identified

is necessarily the best available for the purpose.

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

c. Plaques: Approximate (0◦, 45◦) reflectance measurements, using the PR714, of seven SpectralonTM†

plaques used to convert a lamp’s spectral irradiance

output to diffuse spectral radiance.

d. Voltmeter and shunt intercomparisons.

This report, as in Mueller (1993), does not describe in

detail the uncertainties in the spectroradiometric scales as

realized at the SIRREX; rather, the results are presented

by comparison to independent values where possible. Obviously, the statement of the result of a measurement, such

as the spectral radiance values determined by the transfer

radiometers for the sphere sources, is incomplete without

also stating the uncertainty of the measurement; but at the

time of SIRREX-2, these data were not available. However,

the results for SIRREX-2 are still informative, because uncertainties are demonstrated that reflect the internal consistency of the measurements, as well as the uncertainty

in the absolute calibration of some of the sources and radiometers. For the sphere and plaque studies, SIRREX-2

demonstrates that significant problems remain with regard

to realizing spectral radiance scales; these issues can be resolved only by complete characterization of the sources and

radiometers. This issue, as well as a complete uncertainty

analysis, should be addressed in the next SIRREX (see

Section 3.3).

2. LAMP STANDARDS

All of the participating laboratories base absolute calibrations of irradiance and radiance instrument responsivities on the NIST scale of spectral irradiance, which is transferred to the scientific and engineering community in the

United States via calibrated tungsten-halogen lamps (usually FEL lamps, and less frequently DXWlamps) (Walker

et al. 1987). Some laboratories acquire a calibrated FEL

lamp standard of spectral irradiance directly from NIST,

but more typically, a laboratory will base its irradiance

scale on a lamp which has been calibrated and certified

as traceable to the NIST scale by a commercial standardizing laboratory. In all cases, a laboratory will purchase

additional seasoned, but uncalibrated lamps, and transfer

the spectral irradiance scale from their primary calibrated

lamp using a transfer radiometer. These less expensive

working standards are then used for calibrations to avoid

building up hours on, and expending the useful working

life of, the local primary reference lamp.

A laboratory will periodically intercompare all of their

working standard lamps and their primary reference lamp

to maintain an internally consistent scale of spectral irradiance, and to detect cases when a lamp begins to either

become unstable, or to otherwise fail in a subtle way; a

lamp usually becomes an unreliable source of spectral irradiance long before it burns out. The SIRREX program

† “Spectralon”is a registered trademark of Labsphere, Inc.,

North Sutton, New Hampshire

extends this internal consistency maintenance throughout

the several laboratories participating in the calibration of

instruments for SeaWiFS validation.

2.1 Methods

During SIRREX-2, the spectral irradiance scale of

the GSFC FEL lamp F269 was transferred to 26 other

lamps belonging to the various participating laboratories.

The F269 irradiance scale was recalibrated by NIST in October 1992, to provide a NIST traceable standard as the

basis for intercalibration of all radiometers involved in the

SeaWiFS validation. The second GSFC FEL lamp, F268,

was also recalibrated by NIST to provide a working reference to verify the long term stability of F269, as the

primary tie to the NIST scale of spectral irradiance.

Transfer of the F269 scale of spectral irradiance to other

lamps follows the procedures for spectral irradiance calibrations described in Walker et al. (1987). A small ISIC is

attached, at its exit port, to the entrance slit of an Optronics 746 spectroradiometer—a single-monochromator based

radiometer system with a silicon detector. This spectroradiometer is equipped with an internal chopper, so that

background dark signals are removed electronically.

For SIRREX-2, the 746/ISIC was configured with a

blazed grating yielding a usable spectral range of measurements extending from 350–1,000 nm (in SIRREX-1,

a different grating limited measurements to wavelengths

greater than 400 nm). During and after SIRREX-1, it was

discovered that the spectral responsivity of the 746/ISIC

drifted over time, and that the rate of drift was especially

rapid and erratic during the first two hours of operation

(Mueller 1993). Therefore, for SIRREX-2 measurements,

the 746/ISIC system was powered on to season overnight

prior to its use in irradiance measurements.

Lamp F269 was mounted to illuminate the aperture of

the 746/ISIC, which was placed normal to the center of

the lamp filament at a distance of 50 cm (by convention,

measured to the front surface of the lamp’s electrical connection posts). The lamp was powered on and allowed to

warm up for approximately 20 minutes. The irradiance

responsivity of the 746/ISIC was then determined by measuring the known spectral irradiance output from lamp

F269. The calibrated responsivity of the 746/ISIC was

then used to measure the spectral irradiance emitted by

each of the other lamps. The first measurement is always

made immediately on the reference lamp, F269, to provide

an initial measure of the transfer uncertainty. Each lamp

was then powered down and replaced by the next lamp to

be calibrated, which was allowed to warm up for approximately 15 minutes before its spectral irradiance output was

measured with the 746/ISIC. This procedure was repeated

until all lamps were calibrated.

At approximately two hour intervals, and near the end

of each transfer session, the reference lamp, F269, was measured again to estimate the rate of drift of the radiometer’s

3
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

responsivity through the duration of the entire procedure.

The F269 checks were not performed with this frequency

during SIRREX-1, and unresolved responsivity drift was

a serious source of error in those data. In the analysis of

the SIRREX-2 746/ISIC lamp transfer data, the spectral

responsivity of the 746/ISIC was adjusted to match the

start time of each lamp transfer, by interpolation between

bracketing F269 measurements. The stability of F269 itself was verified by comparison to F268 near the beginning

and end of the entire sequence.

2.2 Results

The spectral irradiance scale of F269, calibrated by

NIST in October 1992, was transferred to 25 other FEL

lamps and 1 DXWlamp on 22–25 June 1993. Figure 1

compares the initial F269 transfer checks on each of the

four days to each other, using the NIST October 1992 calibrated scale as a reference; agreement is within less than

1% at all wavelengths greater than or equal to 400 nm, but

discrepancies increase to as much as 4% at lower wavelengths. This result quantifies the maximum internal uncertainty of the 746/ISIC lamp transfer setup and procedure, but gives no information on the uncertainty of the

F269 scale itself. The transfers of the F269 scale to F268,

and comparison to the October 1992 NIST scale for F268,

provide the best estimate of the overall uncertainty of the

F269 scale and transfer procedure. The transfers of the

F269 scale to F268 (early on 22 June 1993 and late on 24

June 1993) are illustrated in Fig. 2. Agreement with the

NIST (October 1992) F268 calibration scale was less than

1% for wavelengths greater than or equal to 400 nm, indicating that lamp F269 has remained relatively stable since

its October 1992 calibration by NIST. There is, however, a

consistent discrepancy of approximately 0.6% at all wavelengths, which suggests either that the irradiance output

of F269 has increased, or that the output of F268 has decreased in the interim since the two lamps were calibrated

by NIST.

Figures 3–5 illustrate the time series of F269 irradiance

checks measured on 22–24 June, respectively. The responsivity of the 746/ISIC drifted with time on all three days.

Therefore, the responsivity was adjusted to correspond to

the time of each lamp transfer, by interpolating between

bracketing F269 measurements. Drift of the 746/ISIC between F269 checks was less than 1% per hour in all cases.

With this adjustment, it is estimated that the uncertainties

in transfers from F269 were 1% for all lamps.

Irradiance scales of each lamp, as transferred from F269

with the 746/ISIC (responsivity temporally adjusted as

described above), are listed in Tables 1 (GSFC and UM

lamps), 2 (CHORS lamps), 3 (BSI and Satlantic lamps),

4 (UCSB and NOAA), and 5 (National Research Institute

of Far Seas Fisheries [NRIFSF] of Japan, UA, and SBRC).

Spectral irradiance scales transferred from F269 during

SIRREX-2 that were also measured during SIRREX-1, are

illustrated in Figs. 6–16 for lamps F303, F219, F321, F307,

F308, F12G, F12H, 91534, F310, 90572, and 91348, respectively. In these figures, the SIRREX-2 results are also compared with the historical irradiance scales of each lamp,

including the scales derived during SIRREX-1 (Mueller

1993).

The Relative Difference plots for the lamps in Figs. 1–

16 illustrate the factor

δ = 1 − Emeas(λ)

Eref(λ) , (1)

where Emeas and Eref are measured and reference irradiance, respectively. To adjust Emeas, to force agreement

with Eref, take

Eref(λ) = Emeas(λ)

(1 − δ) . (2)

Note that when Emeas exceeds the reference value, the relative difference is negative, and vice versa.

2.3 Discussion

Examination of Figs. 1–5 leads to the conclusion that

the lamp transfers during SIRREX-2 were of much better quality than those attained during SIRREX-1 (Mueller

1993), and that an uncertainty of 1% can be attached to

the transferred scales at wavelengths greater than 400 nm.

This conclusion is based on the apparent stability of FEL

lamp F269, as checked by the comparisons of the irradiance

scales of F268 transferred from F269 with that calibrated

by NIST in October 1992 (Figs. 1 and 2). Agreement is

better than 1% at all wavelengths greater than 400 nm.

Furthermore, although the 746/ISIC drifted by as much

as 2.5% during the course of extended transfer sessions on

each day (Figs. 3–5), significant drifts were monotonic in

time, and rates were always less than 1% per hour. Therefore, the frequent F269 scale checks provide a firm basis for

recalculating 746/ISIC spectral responsivity at any given

time with an estimated uncertainty of less than 1%.

Figures 6–16 illustrate the results for the 11 lamps that

were also measured during SIRREX-1; the results for the

remaining 14 lamps can be found in Tables 1–5. These

SIRREX-2 data are the only available spectral irradiance

determinations for these 14 lamps. Comparison of the

SIRREX-1 and SIRREX-2 results demonstrates that the

uncertainty, as reflected by the internal consistency of the

results, was between 2–6% for SIRREX-1 (with the poorest

results on 31 July 1992) and between 1–2% for SIRREX-2.

The improvement is attributed to the correction of the drift

in the 746/ISIC by remeasuring FEL lamp F269 every two

hours along with the changing of the grating, which resulted in increased throughput below 450 nm.

The SIRREX-2 scale for F307 (Fig. 9) agrees with the

SIRREX-1 (30 July 1992) irradiance scale (above 430 nm)

within 2%, and with the original calibration by Optronics

to within less than 1.5%. The SIRREX-2 scale for F308

4
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 1. Spectral irradiance of FEL lamp F269 measured during initial transfer checks on 22 (o), 23 (×), 24 (+),

and 25 (#) June 1993, compared to the NIST (October 1992) calibrated F269 spectral irradiance scale (solid

line in top panel). The top panel compares spectral irradiance scales in μWcm−2 nm−1, and the bottom panel

illustrates errors relative to the NIST October 1992 calibration.

5
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 2. Spectral irradiance of FEL lamp F268 measured, relative to the scale of lamp F269 on 22 (o) and 24 (+)

June 1993, compared to the NIST (October 1992) calibrated F268 spectral irradiance scale (solid line in top

panel). The top panel compares spectral irradiance scales in μWcm−2 nm−1, and the bottom panel illustrates

errors relative to the NIST October 1992 calibration.

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 3. Temporal change in apparent spectral irradiance of lamp F269, due to drift in the 746/ISIC, during the

lamp spectral irradiance scale transfer of 22 June 1993. The top panel illustrates apparent spectral irradiance

(μWcm−2 nm−1) at 1207, 1358, 1544, and 1741 Pacific Daylight Time (PDT) (see legend in lower panel). The

bottom panel illustrates the deviations at these times relative to the irradiance scale of F269.

7
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 4. Same as Fig. 3 for 23 June 1993 at 0904, 1047, 1233, 1417, 1610, and 1801 PDT.

8
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 5. Same as Fig. 3 for 24 June 1993 at 1024 and 1210 PDT.

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 1. Scales of spectral irradiance for FEL lamps belonging to GSFC (F269, F268, F227, and F315) and UM (F12H

and F12G) measured in units of μWcm−2 nm−1. The F269 scale is the average of the first check transfer on each

of four days, and the F268 scale is the average of measurements on the first and fourth day. The standard deviation

of these mean values for F269 is 0.2% or smaller for wavelengths greater than 400 nm. Lamp current in amperes is

listed in each column head. F12G was measured at two lamp currents (by mistake); 7.907 A is correct. Scales were

transferred from lamp F269 on 22–25 June 1993.

λ F269 F268 F227 F315 F12H F12G F12G

[nm] 8.000 A 8.001 A 8.000 A 8.000 A 8.000 A 7.907 A 8.001 A

350 0.8864 0.8507 0.8788 0.7047 0.7848 0.7641 0.8572

355 1.0002 0.9472 1.0122 0.8076 0.8840 0.8649 0.9661

360 1.1146 1.0765 1.1526 0.8955 1.0017 0.9844 1.0715

365 1.2329 1.1842 1.2726 0.9804 1.1013 1.0853 1.1963

370 1.3496 1.3109 1.3961 1.1013 1.2360 1.2069 1.3236

375 1.4998 1.4483 1.5265 1.2183 1.3505 1.3207 1.4558

380 1.6450 1.5857 1.6856 1.3309 1.4986 1.4659 1.6035

385 1.8159 1.7402 1.8612 1.4723 1.6346 1.6142 1.7528

390 1.9834 1.9104 2.0314 1.6064 1.7798 1.7452 1.9236

395 2.1590 2.0801 2.2147 1.7539 1.9466 1.9067 2.0876

400 2.3441 2.2632 2.3922 1.9060 2.1193 2.0583 2.2790

405 2.5428 2.4558 2.6054 2.0718 2.2926 2.2393 2.4666

410 2.7441 2.6538 2.8048 2.2501 2.4839 2.4188 2.6728

415 2.9587 2.8620 3.0276 2.4328 2.6801 2.6102 2.8708

420 3.1816 3.0777 3.2784 2.6246 2.8924 2.8088 3.0933

425 3.4068 3.3015 3.4815 2.7873 3.1036 3.0599 3.3247

430 3.6475 3.5193 3.7264 3.0242 3.3240 3.2565 3.5549

435 3.8917 3.7615 3.9898 3.2300 3.5460 3.4881 3.7908

440 4.1430 4.0070 4.2389 3.4462 3.7756 3.7071 4.0469

445 4.4027 4.2590 4.5035 3.6691 4.0225 3.9402 4.2937

450 4.6675 4.5090 4.7707 3.8986 4.2631 4.1882 4.5543

455 4.9390 4.7770 5.0612 4.1388 4.5141 4.4466 4.8243

460 5.2192 5.0519 5.3443 4.3801 4.7830 4.6990 5.1036

465 5.5072 5.3258 5.6340 4.6296 5.0440 4.9564 5.3741

470 5.7974 5.6136 5.9313 4.8825 5.3199 5.2218 5.6655

475 6.0899 5.9050 6.2332 5.1394 5.6052 5.5018 5.9605

480 6.3920 6.1961 6.5487 5.4109 5.8743 5.7842 6.2561

485 6.6993 6.4927 6.8527 5.6780 6.1647 6.0565 6.5608

490 7.0060 6.7985 7.1649 5.9446 6.4550 6.3469 6.8637

495 7.3235 7.1023 7.4861 6.2223 6.7398 6.6381 7.1696

500 7.6338 7.4087 7.8107 6.4986 7.0338 6.9308 7.4804

505 7.9547 7.7149 8.1331 6.7803 7.3438 7.2283 7.8040

510 8.2733 8.0362 8.4687 7.0710 7.6418 7.5329 8.1204

515 8.5989 8.3496 8.8006 7.3574 7.9492 7.8356 8.4380

520 8.9254 8.6700 9.1293 7.6510 8.2580 8.1310 8.7624

525 9.2503 8.9815 9.4760 7.9485 8.5590 8.4375 9.0808

530 9.5793 9.3089 9.8064 8.2407 8.8730 8.7515 9.3998

535 9.9084 9.6272 10.1415 8.5380 9.1725 9.0603 9.7119

540 10.2410 9.9508 10.4778 8.8318 9.4978 9.3622 10.0381

545 10.5636 10.2719 10.8191 9.1277 9.7987 9.6753 10.3589

550 10.8937 10.5987 11.1474 9.4279 10.1089 9.9835 10.6810

555 11.2246 10.9168 11.4889 9.7260 10.4288 10.3006 11.0156

560 11.5466 11.2383 11.8194 10.0194 10.7374 10.6002 11.3331

565 11.8725 11.5567 12.1569 10.3155 11.0462 10.9096 11.6505

10
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 1. (cont.) Scales of spectral irradiance for FEL lamps belonging to GSFC (F269, F268, F227, and F315) and

UM (F12H and F12G) measured in units of μWcm−2 nm−1. The F269 scale is the average of the first check transfer

on each of four days, and the F268 scale is the average of measurements on the first and fourth day. The standard

deviation of these mean values for F269 is 0.2% or smaller for wavelengths greater than 400 nm. Lamp current in

amperes is listed in each column head. F12G was measured at two lamp currents (by mistake); 7.907 A is correct.

Scales were transferred from lamp F269 on 22–25 June 1993.

λ F269 F268 F227 F315 F12H F12G F12G

[nm] 8.000 A 8.001 A 8.000 A 8.000 A 8.000 A 7.907 A 8.001 A

570 12.1975 11.8784 12.4886 10.6144 11.3611 11.2154 11.9732

575 12.5163 12.1842 12.8142 10.9157 11.6549 11.5135 12.2915

580 12.8361 12.5045 13.1364 11.1991 11.9642 11.8128 12.6074

585 13.1546 12.8118 13.4679 11.4845 12.2610 12.1246 12.9155

590 13.4707 13.1224 13.7799 11.7758 12.5677 12.4208 13.2312

595 13.7816 13.4243 14.0933 12.0527 12.8619 12.7029 13.5473

600 14.0720 13.7136 14.4096 12.3505 13.1651 13.0206 13.8335

605 14.3881 14.0266 14.7214 12.6412 13.4378 13.2813 14.1337

610 14.6990 14.2936 15.0118 12.8747 13.7051 13.5523 14.4375

615 14.9798 14.6231 15.3420 13.1667 14.0070 13.8756 14.7333

620 15.2759 14.9072 15.6166 13.4297 14.3014 14.0987 14.9984

625 15.5680 15.1668 15.9288 13.7122 14.5853 14.4081 15.3094

630 15.8429 15.4465 16.1860 13.9624 14.8316 14.6863 15.5515

635 16.1070 15.7217 16.4907 14.2537 15.0768 14.9560 15.8531

640 16.3666 15.9731 16.7794 14.4961 15.3702 15.2410 16.0983

645 16.6610 16.2449 17.0357 14.7222 15.5863 15.4583 16.3511

650 16.9314 16.4920 17.3029 14.9676 15.8665 15.7106 16.6386

655 17.1772 16.7470 17.5654 15.2091 16.1162 15.9588 16.9220

660 17.4181 16.9914 17.8369 15.4649 16.3616 16.2090 17.1200

665 17.6675 17.2430 18.0763 15.7280 16.5984 16.4926 17.4201

670 17.9121 17.4557 18.2992 15.9166 16.8479 16.6859 17.6368

675 18.1725 17.7038 18.5698 16.1719 17.0607 16.9526 17.8997

680 18.4000 17.9332 18.8229 16.3652 17.3048 17.1386 18.0899

685 18.6293 18.1784 19.0427 16.5911 17.4998 17.3608 18.3005

690 18.8606 18.3751 19.2290 16.7973 17.7438 17.5608 18.5624

695 19.0793 18.6235 19.4965 17.0375 17.9121 17.7986 18.7637

700 19.2926 18.8225 19.6858 17.2474 18.1366 18.0205 18.9719

705 19.4880 19.0257 19.9258 17.4199 18.3523 18.1747 19.2003

710 19.6847 19.1911 20.0684 17.6135 18.5435 18.4113 19.3927

715 19.8677 19.4113 20.3304 17.8205 18.7266 18.5735 19.5764

720 20.0682 19.5835 20.5267 17.9528 18.9143 18.7571 19.7535

725 20.2471 19.7638 20.6539 18.1303 19.0794 18.9272 19.9388

730 20.4206 19.9461 20.8523 18.3109 19.2194 19.0929 20.1346

735 20.5725 20.1010 21.0413 18.4985 19.4157 19.2613 20.2765

740 20.7189 20.2546 21.1970 18.6885 19.5554 19.4411 20.4282

745 20.8829 20.4056 21.3359 18.8333 19.7506 19.5963 20.5555

750 21.0490 20.5398 21.4703 18.9113 19.9296 19.7227 20.7367

755 21.1622 20.6893 21.6191 19.0907 20.0106 19.8741 20.8943

760 21.3248 20.8605 21.7956 19.2108 20.1343 20.0405 21.0292

765 21.4665 20.9237 21.9189 19.2968 20.2835 20.1509 21.1260

770 21.5864 21.0761 22.0373 19.4794 20.4260 20.2664 21.2826

775 21.7089 21.1973 22.1686 19.6274 20.5268 20.3965 21.3988

780 21.8260 21.3391 22.2772 19.7305 20.6376 20.4979 21.5423

785 21.9640 21.4404 22.3811 19.8093 20.7787 20.6434 21.6154

790 22.0622 21.5188 22.4970 19.9421 20.8608 20.7228 21.7152

11
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 1. (cont.) Scales of spectral irradiance for FEL lamps belonging to GSFC (F269, F268, F227, and F315) and

UM (F12H and F12G) measured in units of μWcm−2 nm−1. The F269 scale is the average of the first check transfer

on each of four days, and the F268 scale is the average of measurements on the first and fourth day. The standard

deviation of these mean values for F269 is 0.2% or smaller for wavelengths greater than 400 nm. Lamp current in

amperes is listed in each column head. F12G was measured at two lamp currents (by mistake); 7.907 A is correct.

Scales were transferred from lamp F269 on 22–25 June 1993.

λ F269 F268 F227 F315 F12H F12G F12G

[nm] 8.000 A 8.001 A 8.000 A 8.000 A 8.000 A 7.907 A 8.001 A

795 22.1550 21.6643 22.6079 20.0718 20.9741 20.8689 21.8465

800 22.2700 21.6874 22.6387 20.1315 21.0947 20.9426 21.9180

805 22.3609 21.7857 22.8110 20.2223 21.1562 21.0102 22.0220

810 22.4180 21.9103 22.8666 20.3089 21.2589 21.1487 22.1399

815 22.5275 21.9939 22.9533 20.4373 21.3235 21.2115 22.2168

820 22.6035 22.0836 23.0337 20.4918 21.4348 21.2739 22.3078

825 22.6451 22.1402 23.1477 20.6197 21.4865 21.4097 22.3175

830 22.7511 22.1840 23.1373 20.6017 21.5484 21.3941 22.4230

835 22.7731 22.2259 23.2799 20.7374 21.6070 21.5320 22.4840

840 22.8303 22.3433 23.3152 20.7870 21.6694 21.5610 22.4631

845 22.9029 22.3687 23.3474 20.8054 21.7275 21.6301 22.5966

850 22.9510 22.4006 23.3512 20.8521 21.7461 21.6331 22.6081

855 22.9851 22.4604 23.4113 20.9643 21.8391 21.6790 22.6940

860 22.9959 22.5068 23.5040 21.0541 21.8642 21.7431 22.7553

865 23.0694 22.5491 23.4940 20.9914 21.9438 21.7797 22.7762

870 23.0911 22.5690 23.5555 21.1034 21.9169 21.8465 22.8115

875 23.1364 22.5857 23.5934 21.1013 21.9918 21.8489 22.7892

880 23.1501 22.6085 23.5724 21.1203 21.9686 21.8562 22.8344

885 23.1776 22.6707 23.5479 21.1876 22.0401 21.8422 22.8932

890 23.1835 22.6585 23.6272 21.1959 22.0634 21.8767 22.8955

895 23.1600 22.6591 23.6508 21.2282 22.0311 21.9482 22.8586

900 23.1760 22.6735 23.6356 21.2503 22.0529 21.9457 22.8697

905 23.2123 22.6898 23.6484 21.2668 22.0685 21.9376 22.8759

910 23.2026 22.6853 23.6262 21.2289 22.0461 21.9088 22.9120

915 23.2058 22.6689 23.6007 21.2340 22.0201 21.8914 22.8772

920 23.1891 22.6730 23.6387 21.2803 22.0687 21.9485 22.8715

925 23.1689 22.6481 23.5737 21.2422 22.0398 21.8898 22.8446

930 23.1291 22.6330 23.6240 21.2875 22.0251 21.9366 22.8293

935 23.1428 22.6128 23.5736 21.2650 22.0096 21.9153 22.8248

940 23.1207 22.6013 23.5651 21.2333 22.0274 21.8940 22.8048

945 23.0954 22.5829 23.5254 21.2215 21.9899 21.8705 22.7628

950 23.0426 22.5360 23.4995 21.2060 21.9981 21.8545 22.7814

955 23.0273 22.4938 23.4535 21.1531 21.9277 21.8232 22.7155

960 23.0176 22.5117 23.4551 21.1502 21.9484 21.7959 22.7441

965 22.9555 22.4351 23.3728 21.1023 21.8336 21.7367 22.6372

970 22.9066 22.3967 23.2697 21.0374 21.8190 21.7139 22.6430

975 22.8892 22.3699 23.3029 21.0967 21.7828 21.7172 22.5781

980 22.8438 22.3415 23.2655 21.0163 21.7862 21.6489 22.5618

985 22.7867 22.2729 23.2093 20.9733 21.6876 21.6370 22.4889

990 22.7360 22.2082 23.1514 20.9729 21.7073 21.5636 22.4482

995 22.6923 22.1662 23.0730 20.8647 21.6225 21.5500 22.3866

1000 22.6271 22.1118 23.0312 20.8228 21.6171 21.4538 22.3396

12
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 2. Scales of spectral irradiance for FEL lamps belonging to SDSU CHORS (90572, 91348, 91349, 91533, and

91534) measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25 June 1993. The scale

under “91349B” is for lamp 91349 with a circular baffle limiting the detector field-of-view to the lamp envelope and

filament, and blocking the base. The lamp current, in amperes, is listed in each column head.

λ 90572 91348 91349 91533 91534 91349B

[nm] 7.108 A 7.656 A 7.656 A 8.000 A 8.000 A 7.656 A

350 0.2480 0.6107 0.5572 0.8757 0.7686 0.5820

355 0.3363 0.7245 0.6891 0.9839 0.8934 0.6890

360 0.3559 0.8066 0.7663 1.0901 0.9953 0.7575

365 0.3892 0.8845 0.8437 1.2149 1.1098 0.8555

370 0.4328 0.9810 0.9435 1.3520 1.2271 0.9380

375 0.4704 1.0895 1.0392 1.4818 1.3571 1.0193

380 0.4980 1.1824 1.1497 1.6133 1.4933 1.1269

385 0.4455 1.0071 0.9619 1.7717 1.6404 0.9687

390 0.4809 1.4300 1.3731 1.9535 1.7813 1.3435

395 0.5371 1.5630 1.4882 2.1256 1.9555 1.4723

400 0.7692 1.7096 1.6252 2.2993 2.1234 1.6060

405 0.8206 1.8539 1.7698 2.5038 2.3044 1.7462

410 0.9071 2.0130 1.9147 2.7084 2.4943 1.8978

415 0.9907 2.1845 2.0760 2.9132 2.6929 2.0563

420 1.0786 2.3547 2.2446 3.1361 2.8987 2.2177

425 1.1576 2.5068 2.3873 3.3539 3.1095 2.3610

430 1.2499 2.7223 2.5620 3.5952 3.3291 2.5398

435 1.3527 2.9050 2.7715 3.8298 3.5596 2.7512

440 1.4596 3.1069 2.9651 4.0800 3.7954 2.9297

445 1.5637 3.3129 3.1654 4.3334 4.0391 3.1218

450 1.6781 3.5232 3.3623 4.6015 4.2877 3.3282

455 1.8112 3.7438 3.5758 4.8751 4.5447 3.5359

460 1.9330 3.9671 3.7934 5.1452 4.8136 3.7521

465 2.0595 4.2016 4.0142 5.4271 5.0788 3.9766

470 2.1928 4.4330 4.2394 5.7161 5.3586 4.1946

475 2.3283 4.6741 4.4693 6.0019 5.6384 4.4257

480 2.4729 4.9257 4.7085 6.2999 5.9234 4.6616

485 2.6149 5.1773 4.9501 6.6017 6.2165 4.9007

490 2.7599 5.4268 5.1905 6.9122 6.5042 5.1376

495 2.9151 5.6909 5.4433 7.2200 6.8067 5.3874

500 3.0669 5.9496 5.6944 7.5308 7.1051 5.6372

505 3.2266 6.2187 5.9550 7.8441 7.4152 5.8907

510 3.3826 6.4881 6.2202 8.1588 7.7189 6.1442

515 3.5512 6.7554 6.4723 8.4787 8.0279 6.4033

520 3.7164 7.0322 6.7401 8.7994 8.3387 6.6662

525 3.8855 7.3044 7.0010 9.1263 8.6589 6.9334

530 4.0551 7.5781 7.2718 9.4454 8.9745 7.1940

535 4.2288 7.8616 7.5388 9.7616 9.2852 7.4623

540 4.4061 8.1422 7.8140 10.0917 9.6085 7.7333

545 4.5862 8.4210 8.0878 10.4135 9.9327 8.0025

550 4.7618 8.7012 8.3632 10.7380 10.2435 8.2729

555 4.9464 8.9926 8.6394 11.0629 10.5642 8.5486

560 5.1256 9.2695 8.9100 11.3916 10.8752 8.8160

565 5.3062 9.5510 9.1810 11.7080 11.1909 9.0850

570 5.4910 9.8318 9.4501 12.0321 11.5131 9.3547

575 5.6778 10.1053 9.7225 12.3466 11.8177 9.6278

580 5.8554 10.3876 10.0035 12.6518 12.1183 9.9004

13
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 2. (cont.) Scales of spectral irradiance for FEL lamps belonging to SDSU CHORS (90572, 91348, 91349, 91533,

and 91534) measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25 June 1993. The

scale under “91349B” is for lamp 91349 with a circular baffle limiting the detector field-of-view to the lamp envelope

and filament, and blocking the base. The lamp current, in amperes, is listed in each column head.

λ 90572 91348 91349 91533 91534 91349B

[nm] 7.108 A 7.656 A 7.656 A 8.000 A 8.000 A 7.656 A

585 6.0389 10.6608 10.2688 12.9725 12.4366 10.1605

590 6.2242 10.9410 10.5328 13.2841 12.7415 10.4269

595 6.4096 11.2171 10.8002 13.5854 13.0390 10.6917

600 6.5841 11.5106 11.1004 13.8967 13.3282 10.9946

605 6.7778 11.7781 11.3498 14.1873 13.6519 11.2070

610 6.9624 12.0312 11.5866 14.5098 13.9281 11.4673

615 7.1540 12.2950 11.8800 14.7852 14.2145 11.7082

620 7.3211 12.5460 12.0813 15.0242 14.4821 11.9434

625 7.4974 12.8158 12.3563 15.3551 14.7550 12.2172

630 7.6933 13.0845 12.6114 15.5955 15.0562 12.4420

635 7.8752 13.3080 12.8905 15.8718 15.3299 12.6782

640 8.0446 13.5285 13.0772 16.1433 15.5722 12.9262

645 8.2200 13.7777 13.2969 16.4301 15.8490 13.1711

650 8.3965 14.0563 13.5771 16.6652 16.1327 13.4151

655 8.5711 14.2897 13.8062 16.9220 16.3848 13.6136

660 8.7361 14.4654 14.0319 17.1742 16.6054 13.8376

665 8.9155 14.7358 14.2428 17.4201 16.8723 14.0742

670 9.0772 14.9260 14.4838 17.6565 17.0970 14.2939

675 9.2488 15.2035 14.6945 17.8997 17.3404 14.5102

680 9.4022 15.3644 14.9125 18.1250 17.5819 14.7032

685 9.5677 15.6126 15.0979 18.3577 17.7858 14.9377

690 9.7492 15.8248 15.2907 18.5768 18.0544 15.1462

695 9.8869 16.0328 15.5042 18.7637 18.2351 15.3161

700 10.0553 16.2154 15.7321 19.0096 18.4496 15.5588

705 10.2028 16.4141 15.9295 19.2239 18.6715 15.7050

710 10.3674 16.6171 16.0796 19.4524 18.8966 15.8951

715 10.4989 16.7934 16.2832 19.5764 19.0728 16.0443

720 10.6449 16.9454 16.4612 19.7535 19.2370 16.2537

725 10.7740 17.1238 16.6241 19.9468 19.4063 16.4202

730 10.9062 17.2959 16.7738 20.0945 19.5974 16.5740

735 11.0596 17.4709 16.9608 20.2765 19.7664 16.7305

740 11.1952 17.5863 17.1013 20.4194 19.9233 16.8815

745 11.3061 17.7614 17.2307 20.5633 20.0566 17.0550

750 11.4394 17.8903 17.3828 20.6967 20.2032 17.2007

755 11.5795 18.0719 17.5601 20.8943 20.3893 17.3190

760 11.6907 18.2167 17.7054 21.0534 20.5347 17.4614

765 11.8040 18.3392 17.8352 21.1511 20.6584 17.6118

770 11.9376 18.4540 17.9455 21.2826 20.8214 17.7144

775 12.0478 18.5814 18.0783 21.3988 20.9293 17.8445

780 12.1413 18.7105 18.1983 21.5102 21.0322 17.9714

785 12.2476 18.8263 18.3382 21.6154 21.1273 18.0717

790 12.3670 18.9385 18.4401 21.7152 21.2880 18.2034

795 12.4661 19.0165 18.5282 21.8101 21.3739 18.3327

800 12.5518 19.1626 18.6446 21.9001 21.4561 18.3617

805 12.6486 19.2740 18.7470 21.9844 21.5326 18.4589

810 12.7289 19.3329 18.7893 22.0547 21.6637 18.5785

815 12.8290 19.4203 18.9542 22.2168 21.7507 18.6568

14
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 2. (cont.) Scales of spectral irradiance for FEL lamps belonging to SDSU CHORS (90572, 91348, 91349, 91533,

and 91534) measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25 June 1993. The

scale under “91349B” is for lamp 91349 with a circular baffle limiting the detector field-of-view to the lamp envelope

and filament, and blocking the base. The lamp current, in amperes, is listed in each column head.

λ 90572 91348 91349 91533 91534 91349B

[nm] 7.108 A 7.656 A 7.656 A 8.000 A 8.000 A 7.656 A

820 12.9107 19.5034 18.9932 22.2111 21.8186 18.7515

825 13.0017 19.6102 19.0480 22.3175 21.9218 18.8495

830 13.0682 19.6798 19.1630 22.3435 21.9857 18.9377

835 13.1428 19.7211 19.2352 22.4144 22.0252 19.0289

840 13.2080 19.7644 19.2881 22.4631 22.1059 19.0236

845 13.2814 19.8312 19.3572 22.5176 22.1225 19.1135

850 13.3415 19.9045 19.4343 22.5689 22.1771 19.1730

855 13.4391 20.0179 19.4569 22.6348 22.2640 19.2541

860 13.4588 19.9815 19.5221 22.6610 22.2782 19.3049

865 13.5392 20.1115 19.5908 22.7678 22.3817 19.3516

870 13.6075 20.1118 19.6192 22.7742 22.4388 19.4188

875 13.6329 20.1345 19.6220 22.7703 22.4042 19.4506

880 13.7042 20.2010 19.6960 22.7983 22.4736 19.4967

885 13.8259 20.2159 19.7279 22.7795 22.4522 19.5031

890 13.8478 20.2739 19.7765 22.8427 22.5278 19.5707

895 13.9289 20.2728 19.7901 22.8241 22.5483 19.5647

900 13.9532 20.2832 19.8068 22.8961 22.5479 19.6131

905 13.9947 20.3192 19.8482 22.8759 22.5395 19.6567

910 14.0488 20.2993 19.8253 22.8454 22.5790 19.6464

915 14.0580 20.3203 19.8510 22.8186 22.5618 19.6560

920 14.0646 20.3368 19.8716 22.8623 22.5605 19.6460

925 14.0974 20.3418 19.8944 22.8201 22.5531 19.6718

930 14.1638 20.3284 19.8663 22.8368 22.5696 19.6748

935 14.1750 20.3185 19.8475 22.8248 22.5313 19.6604

940 14.1838 20.3288 19.8681 22.7724 22.4809 19.6885

945 14.1786 20.3419 19.8394 22.7781 22.5178 19.6364

950 14.2103 20.3051 19.8488 22.7088 22.4408 19.6301

955 14.2464 20.2864 19.8268 22.7155 22.4529 19.6395

960 14.2317 20.2472 19.8421 22.6705 22.4315 19.6373

965 14.2655 20.2262 19.8243 22.6038 22.3694 19.5664

970 14.2477 20.2182 19.8111 22.5850 22.3398 19.5497

975 14.2356 20.2314 19.7320 22.5435 22.3360 19.5282

980 14.2734 20.1884 19.7749 22.4492 22.2302 19.5402

985 14.2557 20.1509 19.7105 22.4993 22.2030 19.4879

990 14.2707 20.1034 19.6514 22.4400 22.1359 19.4220

995 14.2822 20.0775 19.6868 22.3866 22.1574 19.3607

1000 14.2415 20.0476 19.6036 22.3203 22.0828 19.3242

15
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 3. Scales of spectral irradiance for FEL lamps belonging to BSI (91357, F321, and F310), and Satlantic (91615,

91604, and 91591) both measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25 June

1993. The lamp current, in amperes, is listed in each column head.

λ 91357 F321 F310 91615 91604 91591

[nm] 7.901 A 7.901 A 7.901 A 8.001 A 8.001 A 6.947 A

350 0.7028 0.7261 0.6887 0.9174 0.2548 0.9123

355 0.8096 0.8605 0.7883 0.9966 0.3125 1.0083

360 0.9041 0.9417 0.8762 1.1050 0.3556 1.1279

365 1.0025 1.0631 0.9719 1.2331 0.3879 1.2702

370 1.1069 1.1673 1.0871 1.3835 0.4349 1.4068

375 1.2262 1.2818 1.1942 1.5323 0.4675 1.5433

380 1.3333 1.4172 1.3000 1.6772 0.5010 1.7032

385 1.4912 1.5529 1.4359 1.8459 0.4450 1.8740

390 1.6279 1.7118 1.5795 2.0096 0.4848 2.0348

395 1.7729 1.8567 1.7196 2.1857 0.5402 2.2207

400 1.9218 2.0224 1.8782 2.3702 0.7600 2.4130

405 2.0932 2.2048 2.0403 2.5740 0.8329 2.6187

410 2.2666 2.3828 2.2165 2.7867 0.9084 2.8253

415 2.4516 2.5778 2.3952 3.0020 0.9912 3.0484

420 2.6364 2.7750 2.5851 3.2271 1.0810 3.3075

425 2.8042 2.9462 2.7539 3.4658 1.1591 3.5001

430 3.0824 3.1986 2.9796 3.7052 1.2560 3.7646

435 3.2673 3.4054 3.1815 3.9509 1.3557 4.0116

440 3.4954 3.6392 3.3819 4.2092 1.4623 4.2770

445 3.7193 3.8730 3.6092 4.4665 1.5691 4.5388

450 3.9595 4.1120 3.8490 4.7389 1.6814 4.8131

455 4.2097 4.3661 4.0930 5.0141 1.8165 5.0890

460 4.4510 4.6130 4.3314 5.3062 1.9392 5.3842

465 4.7074 4.8835 4.5786 5.5930 2.0638 5.6765

470 4.9673 5.1462 4.8324 5.8921 2.1997 5.9798

475 5.2317 5.4180 5.0945 6.1902 2.3346 6.2913

480 5.5039 5.6956 5.3535 6.4963 2.4793 6.5949

485 5.7807 5.9792 5.6274 6.8115 2.6202 6.9164

490 6.0549 6.2610 5.8958 7.1243 2.7665 7.2330

495 6.3363 6.5466 6.1732 7.4314 2.9214 7.5583

500 6.6256 6.8388 6.4525 7.7505 3.0745 7.8802

505 6.9128 7.1355 6.7356 8.0817 3.2347 8.2131

510 7.2113 7.4347 6.9934 8.4044 3.3944 8.5490

515 7.5052 7.7352 7.3056 8.7302 3.5581 8.8792

520 7.7997 8.0402 7.6035 9.0749 3.7266 9.2184

525 8.0936 8.3424 7.8863 9.3942 3.8931 9.5566

530 8.3940 8.6485 8.1836 9.7214 4.0648 9.8921

535 8.6960 8.9585 8.4835 10.0517 4.2361 10.2304

540 9.0025 9.2692 8.7773 10.3897 4.4173 10.5770

545 9.2976 9.5755 9.0705 10.7152 4.5947 10.9133

550 9.6005 9.8827 9.3688 11.0449 4.7701 11.2527

555 9.9062 10.1955 9.6813 11.3823 4.9478 11.5926

560 10.2045 10.5038 9.9731 11.7058 5.1328 12.0075

565 10.5096 10.8086 10.2705 12.0405 5.3159 12.2952

570 10.8069 11.1189 10.5679 12.3762 5.5005 12.6272

575 11.1085 11.4175 10.8550 12.7042 5.6822 12.9849

16
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 3. (cont.) Scales of spectral irradiance for FEL lamps belonging to BSI (91357, F321, and F310), and Satlantic

(91615, 91604, and 91591) both measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25

June 1993. The lamp current, in amperes, is listed in each column head.

λ 91357 F321 F310 91615 91604 91591

[nm] 7.901 A 7.901 A 7.901 A 8.001 A 8.001 A 6.947 A

580 11.4106 11.7251 11.0920 13.0117 5.8680 13.2847

585 11.7113 12.0332 11.3796 13.3234 6.0566 13.6465

590 12.0014 12.3294 11.6677 13.6682 6.2392 13.9584

595 12.2963 12.6211 11.9576 13.9610 6.4238 14.2349

600 12.6336 12.9156 12.2538 14.2971 6.6054 14.5785

605 12.8591 13.1918 12.5276 14.5620 6.7858 14.8833

610 13.1770 13.4920 12.7707 14.8626 6.9769 15.1832

615 13.4545 13.8127 13.0732 15.2002 7.1617 15.5115

620 13.7284 14.0910 13.3204 15.4373 7.3314 15.7470

625 14.0061 14.3639 13.5866 15.7231 7.5150 16.0593

630 14.2566 14.6154 13.8677 16.0304 7.6961 16.3416

635 14.4564 14.8740 14.1361 16.2763 7.8763 16.6351

640 14.7698 15.1377 14.3718 16.5763 8.0484 16.9108

645 15.0273 15.3977 14.6339 16.8326 8.2249 17.2086

650 15.2763 15.6769 14.8549 17.0911 8.3991 17.4638

655 15.5686 15.9402 15.0955 17.3517 8.5819 17.7278

660 15.7601 16.1406 15.3322 17.6076 8.7469 17.9869

665 16.0156 16.3939 15.6123 17.8583 8.9209 18.2418

670 16.2425 16.6248 15.8184 18.1337 9.0945 18.5489

675 16.4910 16.8774 16.0538 18.3472 9.2575 18.7947

680 16.7143 17.1110 16.2758 18.5555 9.4192 19.0081

685 16.9227 17.3242 16.4704 18.8152 9.5763 19.2155

690 17.1466 17.5474 16.7192 19.0199 9.7519 19.4908

695 17.3488 17.7317 16.9137 19.2335 9.8986 19.6739

700 17.5672 17.9556 17.1145 19.4419 10.0445 19.9118

705 17.8026 18.1672 17.3009 19.6624 10.2209 20.1246

710 17.9710 18.3415 17.5381 19.8847 10.3715 20.3479

715 18.1867 18.5656 17.6880 20.0800 10.5058 20.5206

720 18.3277 18.7486 17.8814 20.2376 10.6417 20.7218

725 18.5173 18.9184 17.9989 20.4213 10.7946 20.8885

730 18.6848 19.0711 18.1860 20.5922 10.9204 21.0498

735 18.8692 19.2850 18.3636 20.7866 11.0628 21.2329

740 19.0226 19.4327 18.5473 20.9069 11.1872 21.4022

745 19.1609 19.5679 18.6753 21.0706 11.3200 21.5707

750 19.3610 19.7314 18.8025 21.2373 11.4319 21.7228

755 19.5003 19.8802 19.0006 21.3678 11.5771 21.9043

760 19.6178 20.0024 19.1205 21.4846 11.6877 22.0041

765 19.7306 20.1201 19.2268 21.6444 11.8105 22.1628

770 19.8897 20.2785 19.4047 21.7438 11.9360 22.3369

775 20.0181 20.4555 19.5206 21.8684 12.0444 22.4051

780 20.1385 20.5152 19.5982 21.9541 12.1311 22.5004

785 20.2150 20.6347 19.7327 22.1035 12.2476 22.6264

790 20.3569 20.7855 19.8640 22.2136 12.3527 22.7475

795 20.4817 20.9031 19.9926 22.3190 12.4681 22.9006

800 20.5619 21.0073 20.0504 22.3440 12.5444 22.9359

805 20.6912 21.0605 20.1021 22.4738 12.6372 23.0384

17
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 3. (cont.) Scales of spectral irradiance for FEL lamps belonging to BSI (91357, F321, and F310), and Satlantic

(91615, 91604, and 91591) both measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25

June 1993. The lamp current, in amperes, is listed in each column head.

λ 91357 F321 F310 91615 91604 91591

[nm] 7.901 A 7.901 A 7.901 A 8.001 A 8.001 A 6.947 A

810 20.7410 21.1852 20.2010 22.5996 12.7477 23.1358

815 20.8522 21.2810 20.3524 22.6440 12.8174 23.2266

820 20.9346 21.3113 20.4059 22.6820 12.8911 23.3099

825 21.0382 21.4267 20.4973 22.7924 12.9908 23.3463

830 21.0498 21.4316 20.5544 22.8206 13.0602 23.4170

835 21.1874 21.5698 20.6023 22.9424 13.1136 23.4803

840 21.2174 21.6072 20.6375 22.9394 13.1921 23.4950

845 21.2468 21.6829 20.7398 22.9916 13.2696 23.5447

850 21.3385 21.7237 20.7665 23.0391 13.3376 23.5876

855 21.3909 21.8023 20.8845 23.1407 13.3884 23.6650

860 21.4590 21.8350 20.9002 23.1498 13.4571 23.6767

865 21.4846 21.8642 20.9370 23.2302 13.5408 23.7599

870 21.5387 21.9501 21.0224 23.2588 13.5937 23.7806

875 21.5823 22.0162 21.0131 23.2375 13.6239 23.7781

880 21.6030 22.0011 21.0668 23.2312 13.6826 23.8083

885 21.6448 22.0371 21.0608 23.3111 13.8485 23.8355

890 21.6455 22.0671 21.1286 23.3237 13.8579 23.8404

895 21.6472 22.0275 21.1692 23.3068 13.8600 23.8240

900 21.6724 22.0826 21.1779 23.2868 13.9346 23.8401

905 21.6603 22.0652 21.1938 23.2796 13.9610 23.8515

910 21.7397 22.0742 21.1803 23.3116 13.9870 23.8444

915 21.7021 22.1181 21.1835 23.2727 14.0428 23.8002

920 21.6858 22.0801 21.2109 23.2956 14.0887 23.8526

925 21.7239 22.0898 21.1811 23.2177 14.1127 23.8030

930 21.7335 22.1250 21.2291 23.2753 14.1179 23.8034

935 21.7121 22.0718 21.1945 23.2161 14.1514 23.7704

940 21.6995 22.0243 21.1852 23.1936 14.1559 23.7442

945 21.6677 22.0593 21.1511 23.1686 14.1875 23.7543

950 21.6591 22.0124 21.1291 23.1404 14.2302 23.6953

955 21.6202 22.0080 21.1070 23.1094 14.2136 23.6346

960 21.6379 21.9637 21.1323 23.0757 14.2565 23.6724

965 21.6240 21.9609 21.0299 23.0056 14.1985 23.5749

970 21.5668 21.9080 21.0421 23.0004 14.2691 23.5780

975 21.5218 21.8537 21.0222 22.9238 14.2453 23.5116

980 21.4226 21.8392 20.9559 22.9057 14.2263 23.4611

985 21.4855 21.7668 20.9695 22.8409 14.2777 23.4263

990 21.3925 21.7477 20.8693 22.8186 14.2987 23.3743

995 21.3351 21.6632 20.8585 22.7686 14.2877 23.3034

1000 21.3267 21.6841 20.8164 22.6764 14.2470 23.2701

18
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 4. Scales of spectral irradiance for FEL lamps belonging to UCSB (F303, F219, F304, and F305) and NOAA

(F307 and F308) both measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25 June

1993. The lamp current, in amperes, is listed in each column head.

λ F303 F219 F304 F305 F307 F308

[nm] 8.001 A 8.000 A 8.000 A 8.000 A 8.000 A 8.000 A

350 0.8754 0.8935 0.8467 0.7570 0.8470 0.8771

355 0.9844 0.9851 0.9619 0.8765 0.9626 0.9969

360 1.0970 1.0985 1.0821 0.9781 1.0765 1.1103

365 1.2382 1.2308 1.2025 1.0937 1.1849 1.2314

370 1.3564 1.3596 1.3191 1.1834 1.3191 1.3780

375 1.5020 1.4900 1.4484 1.3309 1.4514 1.5033

380 1.6469 1.6223 1.5901 1.4370 1.6021 1.6650

385 1.8044 1.8096 1.7537 1.5844 1.7491 1.8238

390 1.9585 1.9549 1.9115 1.7319 1.9106 1.9974

395 2.1510 2.1448 2.0983 1.8975 2.0828 2.1719

400 2.3353 2.3259 2.2758 2.0665 2.2630 2.3683

405 2.5330 2.5254 2.4597 2.2425 2.4545 2.5599

410 2.7348 2.7322 2.6672 2.4280 2.6555 2.7736

415 2.9493 2.9506 2.8838 2.6298 2.8618 2.9807

420 3.1770 3.1711 3.0960 2.8297 3.0753 3.2081

425 3.4048 3.3970 3.3244 3.0299 3.2999 3.4391

430 3.6315 3.6350 3.5473 3.2561 3.5320 3.6808

435 3.8770 3.8770 3.7874 3.4734 3.7731 3.9269

440 4.1252 4.1310 4.0321 3.7089 4.0145 4.1885

445 4.3848 4.3902 4.2878 3.9450 4.2624 4.4340

450 4.6450 4.6550 4.5444 4.1825 4.5217 4.7050

455 4.9202 4.9355 4.8194 4.4357 4.7913 4.9801

460 5.2035 5.2146 5.0943 4.6977 5.0702 5.2684

465 5.4893 5.4955 5.3715 4.9634 5.3476 5.5518

470 5.7853 5.7993 5.6651 5.2321 5.6322 5.8417

475 6.0746 6.0928 5.9617 5.5146 5.9228 6.1458

480 6.3734 6.3910 6.2538 5.7919 6.2150 6.4402

485 6.6828 6.7021 6.5587 6.0753 6.5159 6.7558

490 6.9927 7.0116 6.8596 6.3626 6.8197 7.0669

495 7.3040 7.3286 7.1742 6.6618 7.1282 7.3821

500 7.6294 7.6513 7.4916 6.9513 7.4406 7.6997

505 7.9419 7.9704 7.8003 7.2512 7.7502 8.0255

510 8.2642 8.2996 8.1256 7.5546 8.0654 8.3472

515 8.5805 8.6233 8.4480 7.8657 8.3829 8.6697

520 8.9014 8.9399 8.7637 8.1640 8.7063 9.0005

525 9.2356 9.2759 9.0904 8.4746 9.0207 9.3326

530 9.5637 9.6121 9.4203 8.7915 9.3541 9.6643

535 9.8869 9.9417 9.7486 9.1060 9.6765 9.9934

540 10.2114 10.2693 10.0709 9.4091 9.9902 10.3278

545 10.5410 10.5981 10.4025 9.7231 10.3204 10.6605

550 10.8750 10.9356 10.7364 10.0330 10.6433 10.9917

555 11.2087 11.2695 11.0662 10.3519 10.9716 11.3316

560 11.5295 11.5897 11.3824 10.6607 11.2888 11.6513

565 11.8543 11.9201 11.7018 10.9734 11.6177 11.9757

570 12.1690 12.2372 12.0329 11.2802 11.9355 12.3091

575 12.4889 12.5643 12.3495 11.5812 12.2430 12.6225

19
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 4. (cont.) Scales of spectral irradiance for FEL lamps belonging to UCSB (F303, F219, F304, and F305) and

NOAA (F307 and F308) both measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25

June 1993. The lamp current, in amperes, is listed in each column head.

λ F303 F219 F304 F305 F307 F308

[nm] 8.001 A 8.000 A 8.000 A 8.000 A 8.000 A 8.000 A

580 12.8034 12.8959 12.6604 11.8992 12.5616 12.9466

585 13.1254 13.2086 12.9846 12.2080 12.8760 13.2730

590 13.4465 13.5450 13.3038 12.5110 13.1803 13.5933

595 13.7622 13.8527 13.6082 12.8117 13.4942 13.8967

600 14.0225 14.1564 13.9026 13.0848 13.8261 14.2193

605 14.3881 14.4685 14.2141 13.3969 14.1337 14.5353

610 14.6337 14.7519 14.4894 13.6757 14.3851 14.8036

615 14.9598 15.0701 14.8103 13.9789 14.7074 15.1483

620 15.2435 15.3537 15.0881 14.2523 14.9726 15.3856

625 15.5027 15.6453 15.3858 14.5296 15.2576 15.6714

630 15.8103 15.9469 15.6798 14.7879 15.4997 15.9592

635 16.0605 16.1911 15.9432 15.0684 15.7942 16.2631

640 16.3661 16.4713 16.2019 15.3277 16.0652 16.5105

645 16.6279 16.7604 16.4823 15.5687 16.3050 16.7731

650 16.8652 17.0390 16.7452 15.8639 16.6119 17.0379

655 17.1227 17.2977 17.0014 16.1122 16.8682 17.3517

660 17.3296 17.5264 17.2274 16.3579 17.1270 17.5805

665 17.6260 17.7974 17.5159 16.6306 17.3653 17.8309

670 17.8702 18.0434 17.7589 16.8086 17.5670 18.0637

675 18.1094 18.2919 18.0113 17.0855 17.8438 18.3193

680 18.3432 18.5702 18.2157 17.2941 18.0827 18.5345

685 18.5497 18.7793 18.4854 17.5314 18.2862 18.7580

690 18.7952 18.9768 18.6785 17.7693 18.5408 19.0343

695 18.9901 19.2259 18.8946 17.9740 18.7343 19.2041

700 19.2250 19.4045 19.0905 18.1785 18.9719 19.4492

705 19.4649 19.6473 19.3361 18.4170 19.1397 19.6545

710 19.6220 19.8694 19.5451 18.6027 19.3459 19.8383

715 19.8205 20.0180 19.7338 18.8181 19.5450 20.0170

720 20.0030 20.2299 19.9303 18.9827 19.6889 20.2054

725 20.1473 20.4150 20.0719 19.1604 19.8637 20.3967

730 20.3548 20.5846 20.2483 19.3215 20.0773 20.5922

735 20.5158 20.7721 20.4360 19.5237 20.2446 20.7547

740 20.6945 20.8838 20.5684 19.6851 20.3572 20.9225

745 20.8120 21.0864 20.7574 19.8016 20.5551 21.0467

750 20.9625 21.2219 20.9075 19.9958 20.7206 21.2292

755 21.0831 21.3680 21.0198 20.1334 20.8233 21.3678

760 21.2762 21.5250 21.1882 20.2738 20.9732 21.4766

765 21.3768 21.6613 21.3204 20.3947 21.1260 21.6444

770 21.5037 21.7679 21.4627 20.5303 21.2826 21.8097

775 21.5994 21.8685 21.5657 20.6574 21.3988 21.9020

780 21.7835 22.0061 21.6801 20.7713 21.5084 22.0396

785 21.8938 22.1565 21.7887 20.9309 21.5805 22.1035

790 21.9634 22.2405 21.9459 21.0080 21.7152 22.2136

795 22.0637 22.3190 22.0273 21.1155 21.8101 22.3190

800 22.1303 22.4177 22.0837 21.2300 21.9279 22.4467

805 22.2755 22.5687 22.2471 21.3206 21.9938 22.5114

20
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 4. (cont.) Scales of spectral irradiance for FEL lamps belonging to UCSB (F303, F219, F304, and F305) and

NOAA (F307 and F308) both measured in units of μWcm−2 nm−1; scales were transferred from lamp F269 on 22–25

June 1993. The lamp current, in amperes, is listed in each column head.

λ F303 F219 F304 F305 F307 F308

[nm] 8.001 A 8.000 A 8.000 A 8.000 A 8.000 A 8.000 A

810 22.2929 22.6004 22.2929 21.4473 22.0633 22.5996

815 22.3819 22.6841 22.3723 21.5148 22.1391 22.6829

820 22.5353 22.7913 22.4659 21.5889 22.2393 22.7504

825 22.5951 22.9028 22.5748 21.6904 22.3175 22.8319

830 22.5805 22.8996 22.6204 21.7028 22.3833 22.9001

835 22.7229 23.0029 22.6828 21.8427 22.4738 22.9624

840 22.7801 23.0498 22.7607 21.8727 22.4631 22.9791

845 22.9028 23.1306 22.7931 21.9396 22.5176 23.0706

850 22.8716 23.1870 22.8620 21.9853 22.5689 23.1174

855 22.9264 23.1994 22.8874 22.0686 22.6940 23.1992

860 22.9673 23.2270 22.9478 22.0912 22.7358 23.2643

865 23.0029 23.2686 23.0029 22.1678 22.7383 23.2680

870 23.0345 23.2589 23.0345 22.2118 22.8115 23.2961

875 23.0445 23.3578 23.0631 22.2526 22.7703 23.2920

880 23.1143 23.3316 23.0689 22.2269 22.7983 23.3033

885 23.0976 23.3565 23.1069 22.2867 22.8577 23.3909

890 23.1126 23.4024 23.1213 22.3131 22.8863 23.3760

895 23.1254 23.4023 23.1168 22.2778 22.9017 23.3758

900 23.1340 23.4077 23.1254 22.3301 22.8864 23.3461

905 23.1274 23.4315 23.1108 22.3510 22.8759 23.4141

910 23.1357 23.4120 23.1110 22.3417 22.8535 23.3782

915 23.1318 23.4058 23.1405 22.3449 22.8934 23.3387

920 23.0987 23.3944 23.0658 22.3430 22.8217 23.3444

925 23.0868 23.3724 23.0707 22.3122 22.8117 23.3231

930 23.0714 23.3651 23.1040 22.3535 22.7964 23.3075

935 23.0201 23.3471 23.0201 22.3007 22.8248 23.3465

940 23.0551 23.3073 23.0310 22.2995 22.8048 23.2907

945 22.9730 23.2993 23.0056 22.2551 22.7543 23.2416

950 22.9763 23.2713 23.0091 22.2880 22.7814 23.2383

955 22.9866 23.2093 22.9455 22.2532 22.7235 23.1750

960 22.9095 23.2425 22.9761 22.2435 22.7110 23.1751

965 22.9040 23.1734 22.9040 22.2303 22.6538 23.1061

970 22.8722 23.1365 22.8635 22.1810 22.6606 23.0944

975 22.8197 23.1239 22.8026 22.1684 22.5435 23.0275

980 22.7473 23.0834 22.7912 22.0744 22.5265 22.9848

985 22.7050 23.0123 22.7228 22.0715 22.5076 22.9314

990 22.6519 22.9675 22.7073 22.0012 22.4112 22.8927

995 22.6248 22.9412 22.6533 21.9430 22.3866 22.8450

1000 22.5673 22.8560 22.5976 21.9414 22.3503 22.8261

21
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 5. Scales of spectral irradiance for FEL lamps belonging to NRIFSF (F123), UA (F296 and F297), and the

DXWlamp belonging to SBRC (DXW19) measured in units of μWcm−2 nm−1; scales were transferred from lamp

F269 on 22–25 June 1993. The lamp current, in amperes, is listed in each column head.

λ F123 F296 F297 DXW19 λ F123 F296 F297 DXW19

[nm] 7.108 A 7.656 A 7.656 A 8.000 A [nm] 7.108 A 7.656 A 7.656 A 8.000 A

350 0.7439 0.9401 0.8665 0.7065 590 12.4397 13.9739 13.4476 12.2859

355 0.8536 1.0716 0.9890 0.8019 595 12.7303 14.2888 13.7764 12.5750

360 0.9442 1.1684 1.1077 0.8942 600 13.0284 14.6274 14.0577 12.8739

365 1.0414 1.2975 1.2272 0.9902 605 13.3641 14.9368 14.3747 13.1260

370 1.1497 1.4647 1.3864 1.0979 610 13.6232 15.2221 14.6467 13.4480

375 1.2899 1.5845 1.5045 1.2162 615 13.9111 15.5115 14.9927 13.7519

380 1.4152 1.7549 1.6550 1.3336 620 14.1946 15.7987 15.2307 14.0691

385 1.5553 1.9111 1.8193 1.4788 625 14.4623 16.0852 15.5162 14.3308

390 1.7020 2.1011 1.9774 1.6109 630 14.7400 16.4077 15.7715 14.6063

395 1.8571 2.2838 2.1504 1.7685 635 15.0044 16.6675 16.0611 14.8780

400 2.0224 2.4697 2.3395 1.9230 640 15.2954 16.9435 16.3598 15.1942

405 2.2027 2.6729 2.5401 2.0947 645 15.5300 17.2156 16.5752 15.4545

410 2.3854 2.8993 2.7515 2.2669 650 15.8105 17.4638 16.8782 15.7334

415 2.5764 3.1198 2.9561 2.4494 655 16.0962 17.7546 17.1369 15.9588

420 2.7786 3.3804 3.1775 2.6479 660 16.3036 18.0084 17.4047 16.2532

425 2.9553 3.5870 3.4125 2.8183 665 16.5526 18.2418 17.6392 16.4387

430 3.2098 3.8371 3.6421 3.0591 670 16.7853 18.4791 17.8566 16.7252

435 3.4157 4.1040 3.8933 3.2758 675 17.0393 18.7388 18.1235 16.9526

440 3.6473 4.3513 4.1414 3.4944 680 17.2809 19.0009 18.3436 17.2279

445 3.8849 4.6252 4.3917 3.7201 685 17.4963 19.2314 18.6150 17.4712

450 4.1190 4.8988 4.6548 3.9542 690 17.7156 19.4259 18.7951 17.6814

455 4.3772 5.1807 4.9343 4.2047 695 17.9379 19.6152 19.0279 17.9121

460 4.6325 5.4758 5.2149 4.4558 700 18.1647 19.8668 19.2702 18.1384

465 4.8987 5.7733 5.5073 4.7198 705 18.3495 20.0482 19.4122 18.3523

470 5.1759 6.0694 5.7863 4.9844 710 18.5268 20.3011 19.6379 18.5304

475 5.4464 6.3788 6.0872 5.2553 715 18.7550 20.4577 19.8282 18.6989

480 5.7269 6.6959 6.3863 5.5379 720 18.9753 20.6572 19.9794 18.9788

485 6.0060 7.0104 6.6936 5.8141 725 19.1190 20.8133 20.1714 19.1893

490 6.2948 7.3307 6.9996 6.0986 730 19.2933 21.0095 20.3795 19.3192

495 6.5885 7.6552 7.3058 6.3846 735 19.5089 21.1691 20.5315 19.4520

500 6.8822 7.9811 7.6260 6.6803 740 19.6851 21.3155 20.6789 19.6292

505 7.1818 8.3076 7.9408 6.9751 745 19.7870 21.5242 20.8202 19.8528

510 7.4849 8.6466 8.2726 7.2788 750 19.9758 21.5970 20.9710 20.0317

515 7.7846 8.9781 8.5873 7.5845 755 20.1334 21.7537 21.1312 20.1995

520 8.0933 9.3101 8.9130 7.8888 760 20.2589 21.8846 21.2367 20.3565

525 8.3974 9.6506 9.2387 8.1997 765 20.3472 22.0332 21.3852 20.4781

530 8.7107 9.9882 9.5689 8.5099 770 20.5022 22.2051 21.5462 20.6227

535 9.0272 10.3241 9.8973 8.8194 775 20.6574 22.3044 21.6672 20.7278

540 9.3321 10.6582 10.2147 9.1359 780 20.7549 22.4674 21.7824 20.8926

545 9.6501 10.9998 10.5477 9.4553 785 20.9145 22.5218 21.8594 21.0212

550 9.9622 11.3410 10.8846 9.7690 790 20.9998 22.6408 22.0000 21.1441

555 10.2786 11.6731 11.2102 10.0809 795 21.1055 22.7552 22.1009 21.2281

560 10.5910 12.0676 11.5395 10.4022 800 21.2300 22.7977 22.2151 21.3792

565 10.8830 12.3515 11.8677 10.7194 805 21.2785 22.9169 22.3043 21.4543

570 11.2089 12.6854 12.1945 11.0275 810 21.3987 22.9826 22.3697 21.5273

575 11.5109 13.0491 12.5096 11.3470 815 21.5148 23.0713 22.4498 21.6326

580 11.8254 13.3592 12.8301 11.6544 820 21.5302 23.1236 22.5443 21.7372

585 12.1298 13.7299 13.1418 11.9726 825 21.6562 23.1881 22.5945 21.8026

22
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 5. (cont.) Scales of spectral irradiance for FEL lamps belonging to NRIFSF (F123), UA (F296 and

F297), and the DXWlamp belonging to SBRC (DXW19) measured in units of μWcm−2 nm−1; scales were

transferred from lamp F269 on 22–25 June 1993. The lamp current, in amperes, is listed in each column head.

λ F123 F296 F297 DXW19 λ F123 F296 F297 DXW19

[nm] 7.108 A 7.656 A 7.656 A 8.000 A [nm] 7.108 A 7.656 A 7.656 A 8.000 A

830 21.6933 23.2977 22.6616 21.8664 920 22.3430 23.6392 23.0663 22.5457

835 21.7918 23.3297 22.7030 22.0056 925 22.3254 23.6243 23.0548 22.5375

840 21.8772 23.3363 22.7013 21.9869 930 22.3208 23.6085 23.0394 22.5225

845 21.9207 23.3867 22.7941 22.0435 935 22.3007 23.5748 23.0204 22.5331

850 21.9905 23.4309 22.8040 22.0987 940 22.2842 23.5499 22.9992 22.5473

855 22.0186 23.5490 22.9272 22.1524 945 22.2551 23.5182 22.9571 22.5194

860 22.0570 23.5807 22.9662 22.2782 950 22.2345 23.4994 22.9772 22.4885

865 22.0919 23.6085 23.0032 22.3246 955 22.1980 23.4622 22.9283 22.4529

870 22.2118 23.6315 23.0352 22.3666 960 22.2227 23.4072 22.8767 22.4143

875 22.2289 23.6123 22.9900 22.3336 965 22.1966 23.4246 22.8710 22.4028

880 22.2182 23.6640 23.0508 22.4398 970 22.1810 23.3411 22.8647 22.3877

885 22.2867 23.6753 23.1065 22.4003 975 22.1159 23.2696 22.7509 22.4037

890 22.3131 23.7088 23.1047 22.4262 980 22.0436 23.2668 22.7028 22.3487

895 22.2696 23.7126 23.1171 22.5166 985 22.0479 23.1929 22.6519 22.2892

900 22.2877 23.7378 23.1070 22.5313 990 21.9541 23.1150 22.5964 22.2249

905 22.3013 23.6833 23.0777 22.4765 995 21.9143 23.0742 22.5394 22.2307

910 22.3417 23.7028 23.1278 22.5477 1000 21.9224 23.0431 22.4990 22.1586

915 22.3018 23.6850 23.0740 22.5485

(Fig. 10) agrees with the SIRREX-1 (also 30 July 1992)

scale within 1%, and also agrees with the NIST (October

1992) scale within 1.5% at 400 nm and less than 1% at

all other wavelengths. Similar agreement is seen for F268

(Fig. 2).

For wavelengths greater than 450 nm, most 31 July

1992 SIRREX-1 scales agree with SIRREX-2 within less

than 2%. These include F303 (Fig. 6), F219 (Fig. 7), F321

(Fig. 8), F12G (Fig. 11), F12H (Fig. 12), 91534 (Fig. 13),

and 90572 (Fig. 15) by Hoffman Engineering, Inc. With

the exception of lamp 90572, the SIRREX-2 scales for these

lamps also agree with previous calibrations by lamp vendors, and/or in-house transfers by the lamp owners, within

2%. The original calibration of 90572 (Fig. 15) and the

CHORS transfer to 91348 (Fig. 16), on the other hand,

disagrees with the SIRREX-2 scale by as much as 5% for

wavelengths greater than 450 nm with a total range of

about 10%. This discrepancy varies strongly with wavelength.

The SIRREX-1 (31 July 1992) scale of F310 (Fig. 14)

was approximately 2.5–3% higher in irradiance than its

SIRREX-2 counterpart, for wavelengths greater than

450 nm. The SIRREX-1 (31 July 1992) scale of 91348

(Fig. 16) also disagrees with the SIRREX-2 scale by greater

than 2% for wavelengths between 450 and 550 nm, and by

about 2% at higher wavelengths.

At wavelengths less than 450 nm, all SIRREX-1 lamp

irradiance scales show errors significantly greater than 2%

relative to the corresponding SIRREX-2 scales (Figs. 6–

16). In the SIRREX-2 transfers with the new grating, the

performance of the 746/ISIC is much improved in the 400–

450 nm range, but the measurements between 350–400 nm

show noise and instability characteristics similar to those

seen at 400–450 nm in the SIRREX-1 measurements. An

improved transfer radiometer setup would be required to

support accurate measurements of spectral irradiance at

wavelengths less than 400 nm.

3. SPHERE SOURCES

Integrating spheres are used as sources of spectral radiance by several participating laboratories. The spheres

for which radiance was measured during SIRREX-2 were

the:

1. GSFC sphere, illuminated by 16 internal lamps;

2. CHORS sphere, indirectly illuminated through

four auxiliary spheres, initially by four 125 W

lamps, but for most measurements by four new

275 Wlamps, with flux levels controlled by aperture wheels in front of each lamp;

3. WFF sphere, illuminated by two external lamps,

with flux levels adjusted with entrance apertures;

4. BSI sphere, illuminated with one external lamp

through an adjustable entrance aperture;

5. UCSB sphere, illuminated with a calibrated FEL

lamp at 50 cm through an entrance port, which

may be varied from 2.54–12.7 cm in diameter;

and the

6. NOAA Optronics 420M sphere irradiance source,

illuminated externally, with the lamp distance

23
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

and aperture controls on the input flux level (the

exit port of this sphere has a glass window).

In any case, the purpose of using an integrating sphere is to

create a diffuse source of spatially and angularly uniform

radiance in an exit port of diameter large enough to fill the

field-of-view of a radiometer to be calibrated.

3.1 Methods

Transfer of the NIST scale of spectral irradiance from

a lamp to a scale of spectral radiance for a sphere is accomplished by one of three methods.

In the method used at GSFC, the known irradiance

from an FEL lamp standard of spectral irradiance is first

measured by the 746/ISIC, in a setup identical to that described in Section 2.1 for lamp transfer. The responsivity

of the 746/ISIC to spectral irradiance is thus determined.

The entrance port of the 746/ISIC is then positioned at

a known distance from the exit port of the uncalibrated

integrating sphere, which is illuminated by stable lamp

sources.

The apertures of the two spheres must be parallel and

aligned on the mutual perpendicular joining their two centers. From the distance between the ports of the two

spheres and their respective areas, it is possible to calculate, from the measured irradiance, the radiance in the

exit port of the integrating sphere radiance source (Walker

et al. 1987), and to thus transfer the scale of spectral irradiance from the lamp to a scale of spectral radiance for the

sphere. For more information on this procedure, including

a description of the measurement equation, see Appendix

B in Mueller (1993), or Walker et al. (1987).

A second approach, which was also used during the

SIRREX, is to first determine the spectral radiance scale

of one reference sphere source using the first method discussed above (in this case the GSFC integrating sphere),

and to then use that source to calibrate a narrow field-ofview transfer spectroradiometer. During SIRREX-2, the

radiance scale of the GSFC sphere was transferred to several other spheres using the PR714.

In a third approach, which is used at several laboratories, the spectral irradiance from a calibrated lamp is

directed at normal incidence onto a plaque for which the

Bidirectional Reflectance Distribution Function (BRDF) is

accurately known for at least one angle. The spectral radiance reflected from the plaque is thus calculated as the

product of the BRDF and the known incident spectral irradiance from the lamp. The spectral responsivity of a

radiance sensor is then calibrated by viewing the spectral

radiance reflected from the plaque at the angle for which

the BRDF is known. This technique may be used either

to calibrate an instrument directly by viewing the plaque,

or by using a transfer radiometer to determine the spectral radiance scale of an integrating sphere source. Plaque

measurements of this type were carried out on 25 June

1993.

The wavelength calibrations of the 746/ISIC and PR714

monochromators were tested by measuring the UCSB

sphere while it was illuminated with a mercury lamp with

its spectral lines at 404.7, 435.8, 546.1, 577.0, and 579.0 nm.

3.2 Results

During SIRREX-2, an extensive series of spectral radiance measurements were made on each of the spheres listed

above (Sections 1 and 3). The following radiometers were

used for measurements on some, or all, of the spheres.

a. The 746/ISIC was calibrated for each set of measurements with FEL lamp F269.

b. The PR714 was calibrated on 19 June 1993 using the GSFC sphere radiance scale (transferred

with the 746/ISIC from lamp F269) and with

wavelengths adjusted on the basis of observed

displacement in mercury lines.

c. The BSIXR, a 6-channel filter transfer radiometer, was built and independently calibrated by

BSI.

d. The 6-channel SXR, was manufactured and characterized independently by NIST under contract

for the SeaWiFS Project. The SXR measurements were analyzed using an effective wavelength approach. A separate report will be issued to describe this new instrument.

e. A quantum efficient device (QED), 8-channel filter transfer radiometer, the UAXR, was built

and independently characterized by S. Biggar of

UA. Biggar is analyzing the UAXR data, the

results of which are not included in this report.

f. Three copies of a 7-channel OCR100 filter radiometer, manufactured by Satlantic, were used.

OCR100 data, and the subsequent results (included in this document) were analyzed by S.

McLean of Satlantic.

The wavelength calibration of the 746/ISIC was verified to be within 1 nm by inspecting the resolution of the

mercury lines viewed via the UCSB sphere on 21 June 1993

(D. Menzies, pers. comm.); the data from this test were not

recorded. PR714 measurements of the UCSB sphere, when

illuminated with the mercury lamp (file 36KSSP02.VR1,

recorded at 1702 on 21 June 1993) showed displacements

of −1.7, −1.8, and −1.6 nm at 404.7, 435.8, and 546.1 nm,

respectively, indicating that the PR714 registered wavelengths that were approximately 2 nm low. Based on these

displacement estimates, 2 nm have been added to the wavelengths of all PR714 data.

The spectral radiance responsivity of the PR714 was

calibrated to match the radiance scale of the GSFC sphere,

as transferred from lamp F269 on 19 June 1993. The

746/ISIC was calibrated using lamp F269, and it was then

24
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 6. Spectral irradiance of FEL lamp F303 transferred from F269 on 22 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the original F303 calibration by Optronics, Inc. (+). The top panel shows

spectral irradiance (μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 22 June 1993

SIRREX-2 scale.

25
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 7. Spectral irradiance of FEL lamp F219 transferred from F269 on 22 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the original F219 calibration by Optronics, Inc. (+). The top panel shows

spectral irradiance (μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 22 June 1993

SIRREX-2 scale.

26
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 8. Spectral irradiance of FEL lamp F321 transferred from F269 on 22 June 1993 (solid line), compared

to the SIRREX-1 scale (dashed line) and the original F321 calibration by NIST in February 1991 (o) and the

blackbody interpolation of the NIST calibration (— – – — line). The top panel shows spectral irradiance

(μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 22 June 1993 SIRREX-2 scale.

27
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 9. Spectral irradiance of FEL lamp F307 transferred from F269 on 23 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the original F307 calibration by Optronics, Inc. (o). The top panel shows

spectral irradiance (μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 23 June 1993

SIRREX-2 scale.

28
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 10. Spectral irradiance of FEL lamp F308 transferred from F269 on 23 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the F308 calibration by NIST in October 1992 (+). The top panel shows

spectral irradiance (μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 23 June 1993

SIRREX-2 scale.

29
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 11. Spectral irradiance of FEL lamp F12G transferred from F269 on 24 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the F12G calibration by UM (×). The top panel shows spectral irradiance

(μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 24 June 1993 SIRREX-2 scale.

Also illustrated in the top panel, is the spectral irradiance of F12G operated at 8.000 A (taken in error, on 23

June), rather than the 7.907 A specified for this lamp.

30
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 12. Spectral irradiance of FEL lamp F12H transferred from F269 on 23 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the F12H calibration by UM (×). The top panel shows spectral irradiance

(μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to the 23 June 1993 SIRREX-2 scale.

31
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 13. Spectral irradiance of FEL lamp 91534 transferred from F269 on 23 June 1993 (solid line), compared

to the SIRREX-1 scale (dashed line). The top panel shows spectral irradiance (μWcm−2 nm−1) and the bottom

panel illustrates discrepancies relative to the 23 June 1993 SIRREX-2 scale.

32
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 14. Spectral irradiance of FEL lamp F310 transferred from F269 on 23 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line). The top panel shows spectral irradiance (μWcm−2 nm−1) and the bottom

panel illustrates discrepancies relative to the 23 June 1993 SIRREX-2 scale.

33
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 15. Spectral irradiance of FEL lamp 90572 transferred from F269 on 23 June 1993 (solid line), compared

to the SIRREX-1 scale (dashed line) and the original 90572 calibration by Hoffman Engineering, Inc. (o). The

top panel shows spectral irradiance (μWcm−2 nm−1) and the bottom panel illustrates discrepancies relative to

the 23 June 1993 SIRREX-2 scale.

34
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 16. Spectral irradiance of FEL lamp 91348 transferred from F269 on 23 June 1993 (solid line), compared to

the SIRREX-1 scale (dashed line) and the original 91348 calibration by CHORS using 90572 (Hoffman, Fig. 15)

(×). The top panel shows spectral irradiance (μWcm−2 nm−1) and the bottom panel illustrates discrepancies

relative to the 23 June 1993 SIRREX-2 scale.

35
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

used to measure the spectral radiance of the sphere (Section 3.1). Three separate measurements were then made

of the sphere’s spectral radiance with the PR714 (all using

its small aperture setting). The 746/ISIC (F269) sphere

radiances, measured from 350–1,000 nm in increments of

10 nm, were determined on the 4 nm interval scale of the

PR714 for the range from 382–1,070 nm (after the +2 nm

correction described above). Below 1,000 nm, this adjustment was made by cubic least-squares interpolation of the

746/ISIC values; beyond 1,000 nm, extrapolation was used.

Listed in Table 6 are the interpolated 746/ISIC measurements of the GSFC sphere; the results of the three

PR714 measurements (on separate columns); and calibration factors by which the PR714 radiances, which were

acquired using the small aperture, must be multiplied to

match the GSFC sphere scale. These calibration factors,

F ̄(λ), are the average of the three calibration factors F(λ)

that correspond to each PR714 measurement. The standard deviations, σ, reported in Table 6, which are no larger

than 0.1% for wavelengths beyond 400 nm, can be taken to

represent one component of uncertainty in the transfer.

In the course of the series of PR714 measurements

of the CHORS sphere on 18–19 June 1993, the instrument’s aperture setting was switched (between spectral

scans) from small to large, yielding four comparisons between the PR714 responses at the two settings, where each

pair of measurements was made with a fixed target radiance and measurement geometry. The ratios of these

responses are listed in Table 7, together with the average.

These PR714 responsivity ratios decrease rapidly from 10%

at 382 nm, then to near 5%, and then more gradually to

stabilize between 3% and 4% at wavelengths greater than

500 nm. To calibrate PR714 radiance data to match the

scale of the GSFC sphere when the instrument is set with

its large aperture, it is necessary to divide by the ratios of

Table 7, after first multiplying the raw data by the corresponding calibration factors in Table 6 (derived from

PR714 small aperture data). This additional correction

was applied to all large aperture PR714 data presented

here.

The differences noted above (3–10%) between small

and large aperture readings of the CHORS sphere with

the PR714, are far greater than the differences at either

aperture setting when the sphere was viewed first normal

to the exit port and then from 10% off axis (less than 1%

at all wavelengths) on 18 June 1993 (Table 7). This degree

of agreement between two different viewing geometries, in

each case, supports the assumption that the observed differences between small and large aperture readings were

not an artifact of radiance inhomogeneity in the sphere,

but are rather a characteristic of the PR714 itself.

As a general comment, the Relative Difference curves

presented in Figs. 17–20 and 22–26 (lower panels) follow

the same non-intuitive convention as the counterpart relative irradiance differences in Figs. 1–16, as explained at

the end of Section 2.2 above.

3.2.1 The GSFC Sphere

Spectral radiance of the GSFC sphere was measured

with the 746/ISIC on 15, 16, and 19 June 1993, shortly after the radiometer’s calibration with lamp F269 (Tables 6

and 8). The calibrated sphere radiance scales (746/ISIC)

from these three days are compared with each other and

with the radiance scale of the sphere during SIRREX-1

(in July 1992), in Fig. 17. During SIRREX-2 in June

1993, the radiance scale of the GSFC sphere had decreased

by approximately 3% at all wavelengths since July 1992.

From day to day during the first week of SIRREX-2, the

sphere radiance scale, as measured and calibrated with the

746/ISIC and lamp F269, appeared to be stable within approximately 1% (Fig. 17, lower panel). However, these relative differences, which are referenced to the SIRREX-1 results, are wavelength dependent with about a 1% variability.

In addition to the calibration measurements on 19 June

1993 (Table 8), the radiance of the GSFC sphere was measured with the PR714 on 21–23 June 1993 (Tables 9 and

10). The first PR714 scan on 21 June was recorded before

the sphere had fully warmed up, and overall radiance was

about 3% low at all wavelengths, relative to the GSFC scale

of 19 June (746/ISIC and F269) and to the subsequent

measurements on that day; the measurements made following adequate sphere warm-up agreed with the 19 June

(746/ISIC and F269) scale within approximately 1%, and

agreement between these three (at approximately 1 hour

intervals) was even better (Fig. 19, lower panel).

PR714 measurements of the GSFC sphere on 22 June

are shown in Fig. 20; these readings were made in rapid

sequence over a total span of one hour, with the first six

clustered in the three minutes between 0918 and 0921 PDT.

The goal was to study the effect of varying the lens focus

distance setting of the PR714. Internal agreement was

generally within less than 1%, except for 1) the scan at

0921 PDT, which disagreed with the other five by approximately 1.5%, and 2) with the reading at 1013 PDT (Fig. 20,

lower panel). All of these PR714 radiance spectra exceeded

the 19 June scale of the sphere, by approximately 1% at

400 nm, and the difference monotonically increased to 3%

at 1000 nm, with the 0921 outlier scan being in slightly

better agreement. These scans on 22 June were made with

the radiometer’s object distance fixed at 86.4 cm, and the

lens focus distance setting was varied from 0.3 m to infinity (∞). Scans at 0918 and 1013 were made in the usual

way, i.e., the PR714 was focused on the exit aperture of

the sphere. The outlier scan at 0921 (above) was taken

with a 0.3 m focus distance.

On 19 June 1993, SXR radiance measurements (corrected for out-of-field sensitivity) of the GSFC sphere, agree

with the 746/ISIC and the calibrated PR714 data within

less than 2% at all wavelengths, and within less than 0.5%

for 450 <λ< 700 nm (Table 8). On subsequent days, the

SXR data depart from the PR714 measurements by 2–5%

36
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

37
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

38
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

40
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

42
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 7. Ratios of large aperture radiances to small aperture radiances for the PR714, from paired measurements

(taken in rapid succession) of the CHORS sphere at a fixed geometry, and the average ratio. To correct large aperture

PR714 radiances, as initially calibrated using Table 6, simply divide by the average ratio (below) at each wavelength

(λ).

Column Large Aperture Small Aperture Date Times [PDT]

File File

1 test 002 test 001 18 June 1993 1810/1805

2 test 004 test 003 18 June 1993 1816/1815

3 36icsp11.Lr1 36icsp11.Lr0 19 June 1993 1046/1045

4 36icsp11.Lr3 36icsp11.Lr2 19 June 1993 1050/1048

λ [nm] (1) (2) (3) (4) Average λ [nm] (1) (2) (3) (4) Average

382 1.1088 1.1028 1.1175 1.1162 1.1113 554 1.0352 1.0354 1.0356 1.0341 1.0351

386 1.0510 1.0637 1.0810 1.0590 1.0637 558 1.0333 1.0327 1.0340 1.0318 1.0329

390 1.0566 1.0732 1.0673 1.0977 1.0737 562 1.0316 1.0303 1.0310 1.0294 1.0306

394 1.0920 1.0665 1.0861 1.0726 1.0793 566 1.0283 1.0277 1.0279 1.0279 1.0280

398 1.0889 1.0860 1.0912 1.0664 1.0831 570 1.0324 1.0311 1.0313 1.0307 1.0314

402 1.0653 1.0608 1.0774 1.0624 1.0665 574 1.0355 1.0347 1.0334 1.0339 1.0344

406 1.0491 1.0484 1.0549 1.0465 1.0497 578 1.0420 1.0420 1.0427 1.0432 1.0425

410 1.0457 1.0478 1.0437 1.0442 1.0454 582 1.0481 1.0476 1.0485 1.0481 1.0481

414 1.0524 1.0567 1.0582 1.0552 1.0556 586 1.0459 1.0471 1.0482 1.0462 1.0469

418 1.0600 1.0592 1.0596 1.0639 1.0607 590 1.0391 1.0408 1.0392 1.0396 1.0397

422 1.0435 1.0455 1.0464 1.0428 1.0446 594 1.0325 1.0331 1.0340 1.0330 1.0331

426 1.0407 1.0419 1.0402 1.0394 1.0406 598 1.0273 1.0253 1.0279 1.0267 1.0268

430 1.0457 1.0459 1.0462 1.0469 1.0462 602 1.0265 1.0256 1.0264 1.0241 1.0257

434 1.0537 1.0548 1.0516 1.0513 1.0528 606 1.0281 1.0268 1.0281 1.0272 1.0276

438 1.0610 1.0572 1.0580 1.0587 1.0587 610 1.0304 1.0302 1.0295 1.0292 1.0298

442 1.0406 1.0380 1.0371 1.0395 1.0388 614 1.0342 1.0335 1.0348 1.0325 1.0338

446 1.0361 1.0369 1.0360 1.0326 1.0354 618 1.0420 1.0415 1.0428 1.0412 1.0419

450 1.0398 1.0406 1.0429 1.0381 1.0403 622 1.0422 1.0416 1.0436 1.0444 1.0430

454 1.0444 1.0414 1.0451 1.0419 1.0432 626 1.0387 1.0403 1.0407 1.0402 1.0400

458 1.0497 1.0484 1.0468 1.0509 1.0489 630 1.0366 1.0366 1.0396 1.0358 1.0371

462 1.0576 1.0569 1.0574 1.0592 1.0578 634 1.0326 1.0321 1.0354 1.0305 1.0326

466 1.0439 1.0426 1.0432 1.0430 1.0432 638 1.0300 1.0292 1.0317 1.0282 1.0298

470 1.0334 1.0357 1.0373 1.0355 1.0355 642 1.0284 1.0280 1.0298 1.0272 1.0283

474 1.0305 1.0333 1.0349 1.0337 1.0331 646 1.0326 1.0319 1.0342 1.0322 1.0327

478 1.0378 1.0373 1.0377 1.0354 1.0370 650 1.0339 1.0308 1.0345 1.0319 1.0328

482 1.0460 1.0449 1.0464 1.0442 1.0454 654 1.0349 1.0318 1.0333 1.0332 1.0333

486 1.0605 1.0585 1.0603 1.0587 1.0595 658 1.0367 1.0359 1.0392 1.0348 1.0367

490 1.0505 1.0500 1.0508 1.0506 1.0505 662 1.0343 1.0345 1.0371 1.0346 1.0351

494 1.0405 1.0405 1.0417 1.0411 1.0409 666 1.0348 1.0338 1.0358 1.0343 1.0347

498 1.0299 1.0304 1.0320 1.0302 1.0306 670 1.0381 1.0379 1.0391 1.0371 1.0380

502 1.0304 1.0292 1.0295 1.0282 1.0293 674 1.0341 1.0335 1.0350 1.0335 1.0340

506 1.0383 1.0387 1.0370 1.0365 1.0376 678 1.0297 1.0291 1.0290 1.0288 1.0292

510 1.0429 1.0410 1.0425 1.0415 1.0420 682 1.0330 1.0337 1.0335 1.0321 1.0331

514 1.0457 1.0450 1.0465 1.0467 1.0460 686 1.0330 1.0337 1.0333 1.0303 1.0326

518 1.0457 1.0468 1.0464 1.0451 1.0460 690 1.0322 1.0317 1.0337 1.0296 1.0318

522 1.0393 1.0393 1.0413 1.0394 1.0398 694 1.0327 1.0328 1.0320 1.0321 1.0324

526 1.0313 1.0276 1.0288 1.0284 1.0290 698 1.0344 1.0333 1.0335 1.0336 1.0337

530 1.0284 1.0277 1.0283 1.0276 1.0280 702 1.0317 1.0306 1.0327 1.0314 1.0316

534 1.0361 1.0341 1.0357 1.0336 1.0349 706 1.0298 1.0289 1.0311 1.0286 1.0296

538 1.0394 1.0384 1.0396 1.0376 1.0388 710 1.0278 1.0285 1.0309 1.0289 1.0290

542 1.0408 1.0418 1.0411 1.0401 1.0409 714 1.0255 1.0268 1.0270 1.0254 1.0262

546 1.0493 1.0499 1.0487 1.0495 1.0494 718 1.0254 1.0265 1.0275 1.0251 1.0261

550 1.0458 1.0449 1.0468 1.0461 1.0459 722 1.0328 1.0319 1.0333 1.0305 1.0321

43
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 7. (cont.) Ratios of large aperture radiances to small aperture radiances for the PR714, from paired measurements (taken in rapid succession) of the CHORS sphere at a fixed geometry, and the average ratio. To correct large

aperture PR714 radiances, as initially calibrated using Table 6, simply divide by the average ratio (below) at each

wavelength (λ).

λ [nm] (1) (2) (3) (4) Average λ [nm] (1) (2) (3) (4) Average

726 1.0335 1.0319 1.0336 1.0307 1.0324 898 1.0165 1.0163 1.0207 1.0168 1.0176

730 1.0354 1.0352 1.0368 1.0339 1.0353 902 1.0232 1.0235 1.0263 1.0230 1.0240

734 1.0417 1.0408 1.0424 1.0404 1.0413 906 1.0323 1.0341 1.0352 1.0305 1.0330

738 1.0438 1.0454 1.0461 1.0428 1.0445 910 1.0481 1.0475 1.0486 1.0442 1.0471

742 1.0462 1.0467 1.0480 1.0440 1.0462 914 1.0500 1.0510 1.0537 1.0501 1.0512

746 1.0487 1.0482 1.0492 1.0466 1.0482 918 1.0472 1.0482 1.0494 1.0473 1.0480

750 1.0413 1.0414 1.0448 1.0402 1.0419 922 1.0385 1.0409 1.0403 1.0363 1.0390

754 1.0285 1.0280 1.0302 1.0278 1.0286 926 1.0311 1.0350 1.0348 1.0310 1.0330

758 1.0207 1.0217 1.0226 1.0205 1.0214 930 1.0298 1.0277 1.0321 1.0268 1.0291

762 1.0302 1.0300 1.0316 1.0285 1.0301 934 1.0346 1.0355 1.0368 1.0329 1.0350

766 1.0294 1.0298 1.0330 1.0293 1.0304 938 1.0363 1.0368 1.0381 1.0320 1.0358

770 1.0245 1.0242 1.0259 1.0231 1.0244 942 1.0308 1.0327 1.0378 1.0320 1.0333

774 1.0215 1.0212 1.0233 1.0200 1.0215 946 1.0345 1.0313 1.0376 1.0354 1.0347

778 1.0230 1.0215 1.0235 1.0216 1.0224 950 1.0343 1.0350 1.0349 1.0364 1.0351

782 1.0254 1.0257 1.0290 1.0231 1.0258 954 1.0367 1.0380 1.0390 1.0366 1.0376

786 1.0299 1.0313 1.0327 1.0301 1.0310 958 1.0319 1.0347 1.0397 1.0362 1.0356

790 1.0333 1.0349 1.0334 1.0331 1.0337 966 1.0327 1.0358 1.0378 1.0374 1.0359

794 1.0382 1.0380 1.0401 1.0368 1.0383 970 1.0323 1.0351 1.0355 1.0363 1.0348

798 1.0407 1.0415 1.0421 1.0398 1.0410 974 1.0300 1.0335 1.0349 1.0316 1.0325

802 1.0394 1.0387 1.0417 1.0392 1.0398 978 1.0328 1.0291 1.0327 1.0299 1.0311

806 1.0354 1.0349 1.0375 1.0349 1.0357 982 1.0312 1.0324 1.0367 1.0312 1.0329

810 1.0339 1.0340 1.0366 1.0349 1.0348 986 1.0330 1.0310 1.0364 1.0359 1.0341

814 1.0336 1.0353 1.0370 1.0346 1.0351 990 1.0289 1.0308 1.0292 1.0301 1.0297

818 1.0306 1.0321 1.0314 1.0294 1.0309 994 1.0275 1.0279 1.0328 1.0274 1.0289

822 1.0320 1.0317 1.0332 1.0310 1.0320 998 1.0254 1.0320 1.0298 1.0236 1.0277

826 1.0327 1.0320 1.0360 1.0333 1.0335 1002 1.0260 1.0209 1.0315 1.0280 1.0266

830 1.0290 1.0288 1.0333 1.0291 1.0300 1006 1.0281 1.0275 1.0320 1.0293 1.0292

834 1.0298 1.0302 1.0329 1.0300 1.0307 1010 1.0319 1.0358 1.0347 1.0352 1.0344

838 1.0302 1.0322 1.0333 1.0314 1.0318 1014 1.0305 1.0346 1.0310 1.0277 1.0309

842 1.0296 1.0303 1.0324 1.0301 1.0306 1018 1.0294 1.0267 1.0368 1.0261 1.0298

846 1.0303 1.0294 1.0322 1.0294 1.0303 1022 1.0343 1.0328 1.0380 1.0328 1.0345

850 1.0333 1.0322 1.0350 1.0323 1.0332 1026 1.0367 1.0346 1.0340 1.0308 1.0340

854 1.0330 1.0324 1.0353 1.0322 1.0332 1030 1.0404 1.0370 1.0383 1.0341 1.0374

858 1.0311 1.0324 1.0340 1.0324 1.0325 1034 1.0372 1.0386 1.0409 1.0387 1.0388

862 1.0342 1.0369 1.0370 1.0342 1.0356 1038 1.0314 1.0300 1.0336 1.0339 1.0322

866 1.0363 1.0383 1.0396 1.0367 1.0377 1042 1.0356 1.0401 1.0297 1.0278 1.0333

870 1.0335 1.0353 1.0375 1.0346 1.0352 1046 1.0393 1.0351 1.0377 1.0360 1.0370

874 1.0333 1.0329 1.0363 1.0324 1.0337 1050 1.0448 1.0365 1.0362 1.0294 1.0367

878 1.0352 1.0354 1.0388 1.0344 1.0360 1054 1.0462 1.0363 1.0316 1.0300 1.0361

882 1.0330 1.0343 1.0360 1.0320 1.0338 1058 1.0325 1.0290 1.0325 1.0116 1.0264

886 1.0284 1.0309 1.0321 1.0289 1.0301 1062 1.0224 1.0278 1.0575 1.0309 1.0347

890 1.0265 1.0290 1.0294 1.0265 1.0279 1066 1.0161 1.0439 1.0249 1.0213 1.0266

894 1.0200 1.0207 1.0221 1.0198 1.0206 1070 1.0170 1.0162 1.0050 1.0284 1.0167

44
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 17. Spectral radiance scale of the GSFC sphere, as referenced to FEL lamp F269 during SIRREX-2 in

June 1993, and comparison to the sphere’s spectral radiance scale during SIRREX-1 in July 1992. The top panel

illustrates the average 746/ISIC F269 scale transfer (solid line) on 15, 16, and 19 June 1993, and compares it

to scales of the individual days and SIRREX-1 (dashed lines). The bottom panel illustrates the relative change

between July 1992, and June 1993. The radiance is in μWcm−2 nm−1 sr−1 and wavelength is in nanometers.

45
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 18. Calibration factors to adjust the PR714 spectroradiometer raw radiance values to the spectral irradiance scale of the GSFC sphere, as referenced to FEL lamp F269 on 19 June 1993. The top panel illustrates

the mean scaling ratio (solid line), derived from the average of three PR714 measurements at 1705, 1710, and

1725 PDT. The bottom panel illustrates the relative differences in the three individual measurements from the

mean.

46
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 19. Spectral radiance of the GSFC sphere measured with the PR714 at 1127 (before sphere warm-up),

1343, 1448, and 1600 PDT on 21 June 1993, compared with the radiance scale of the sphere on 19 June 1993

(referenced to FEL lamp F269) [solid curve in top panel]. Also shown are SXR radiances at 1120, 1352, and

1451 PDT (see above key). The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the sphere, and

the bottom panel illustrates the departures of the PR714 and SXR radiances relative to the F269 calibrated

scale.

47
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 20. Spectral radiance of the GSFC sphere measured with the PR714 at 0918, 0919, 0919.5, 0920, 0920.5,

0921, and 1013; and the SXR at 1030 PDT on 22 June 1993, compared with the radiance scale of the sphere

on 19 June 1993 (referenced to FEL lamp F269) [solid curve in top panel]. The top panel illustrates spectral

radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom panel illustrates the departures of the PR714 and

SXR radiances relative to the F269 calibrated scale.

48
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 8. GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISC on 15, 16, and

19 June 1993; BSIXR, PR714 (small aperture) and the SXR on 19 June 1993 (dates and times are given in PDT).

λ 746 746 746 746 BSIXR 746 PR714 PR714 SXR PR714

[nm] 15 June 15 June 16 June 16 June 19 June 19 June 19 June 19 June 19 June 19 June

1255 1546 1420 1425 1549 1620 1705 1710 1715 1725

350 0.5695 0.5790 0.5687 0.5736 0.5618

360 0.9062 0.9252 0.9159 0.9036 0.8775

370 1.1211 1.1141 1.1277 1.1273 1.0993

380 1.3705 1.3947 1.8130 1.8032 1.7590

382 1.7718 1.7372 1.8113

386 2.0000 1.9687 1.9808

390 2.2058 2.2380 2.2371 2.2433 2.1992 2.2237 2.1602 2.2174

394 2.4340 2.4199 2.4124

398 2.6489 2.6467 2.6457

400 2.7180 2.7481 2.7585 2.7615 2.7134

402 2.8779 2.8769 2.8716

406 3.1265 3.0991 3.1318

410 3.3607 3.3910 3.4436 3.4436 3.3873 3.3732 3.3658 3.3976

411 3.3627

412 3.5346

414 3.6438 3.6555 3.6609

418 3.9384 3.9542 3.9320

420 4.0937 4.1318 4.1572 4.1626 4.1114

422 4.2499 4.2395 4.2364

426 4.5543 4.5574 4.5481

430 4.8674 4.9029 4.9276 4.9276 4.8796 4.8792 4.8719 4.8719

434 5.2244 5.1887 5.1982

438 5.5437 5.5292 5.5478

440 5.6914 5.7170 5.7446 5.7446 5.6977

441 5.6778

442 5.8818 5.8738 5.8919

443 5.8817

446 6.2201 6.2242 6.2434

450 6.5592 6.5957 6.6116 6.6209 6.5719 6.5765 6.5847 6.5765

454 6.9336 6.9480 6.9315

458 7.3019 7.3174 7.3112

460 7.4966 7.5300 7.5385 7.5385 7.5054

462 7.6900 7.6869 7.7093

466 8.0813 8.0923 8.1032

470 8.5058 8.5391 8.5517 8.5566 8.5065 8.5008 8.4969 8.5008

474 8.9191 8.9191 8.9100

478 9.3303 9.3283 9.3633

480 9.5562 9.5939 9.5900 9.5900 9.5541

482 9.7576 9.7783 9.7804

486 10.2042 10.2135 10.2104

487 10.3087

490 10.6519 10.6908 10.6884 10.6884 10.5514 10.6503 10.6511 10.6511 10.6511

494 11.1029 11.0830 11.1029

498 11.5502 11.5502 11.5303

500 11.7998 11.8327 11.8020 11.8020 11.7681

502 11.9898 11.9898 11.9998

506 12.4403 12.4505 12.4606

49
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 8. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISC on

15, 16, and 19 June 1993; BSIXR, PR714 (small aperture) and the SXR on 19 June 1993 (dates and times are given

in PDT).

λ 746 746 746 746 BSIXR 746 PR714 PR714 SXR PR714

[nm] 15 June 15 June 16 June 16 June 19 June 19 June 19 June 19 June 19 June 19 June

1255 1546 1420 1425 1549 1620 1705 1710 1715 1725

510 12.9692 13.0122 12.9733 12.9733 12.9043 12.9024 12.9228 12.9228

514 13.3852 13.3751 13.4055

518 13.8744 13.8543 13.8744

520 14.1459 14.1915 14.1517 14.1517 14.1203

522 14.3620 14.3520 14.3421

526 14.8476 14.8476 14.8277

530 15.3414 15.4160 15.3895 15.3895 15.3351 15.3269 15.3369 15.3369

534 15.8254 15.8355 15.8254

538 16.3429 16.3225 16.3122

540 16.5806 16.6164 16.6103 16.6103 16.5811

542 16.8137 16.8239 16.8341

546 17.3186 17.3288 17.3186

547 17.5083

550 17.8322 17.8721 17.8702 17.8519 17.8008 17.8159 17.8159 17.8260

554 18.3209 18.3209 18.3109

558 18.8190 18.8091 18.8289

560 19.1194 19.1481 19.1278 19.1092 19.0763

562 19.3095 19.3195 19.3394

566 19.8213 19.8413 19.8213

570 20.3682 20.4130 20.3689 20.3287 20.3339 20.3268 20.3370 20.3370

574 20.8459 20.8357 20.8357

578 21.3400 21.3502 21.3400

580 21.5949 21.6604 21.6390 21.5926 21.6055

582 21.8387 21.8489 21.8489

586 22.3483 22.3382 22.3483

589 21.9760

590 22.8519 22.9014 22.8665 22.8390 22.8386 22.8404 22.8404 22.8404

594 23.3182 23.3576 23.3182

598 23.8069 23.8464 23.7971

600 24.0965 24.0818 23.9879 23.9543 24.0476

602 24.2903 24.3200 24.2803

606 24.7734 24.7834 24.7734

610 25.2593 25.3539 25.3109 25.2796 25.2491 25.2433 25.2735 25.2533

614 25.7256 25.7460 25.7358

618 26.2098 26.2200 26.2098

620 26.4666 26.5580 26.5293 26.4984 26.4662

622 26.6816 26.6816 26.7019

626 27.1669 27.1669 27.1467

630 27.6240 27.7387 27.6890 27.6580 27.6353 27.6381 27.6180 27.6281

634 28.0881 28.1081 28.0781

638 28.5557 28.5457 28.5457

640 28.7435 28.8637 28.8097 28.7940 28.7625

642 29.0137 28.9640 29.0236

646 29.4413 29.4313 29.4613

650 29.9002 30.0414 29.9494 29.9176 29.8720 29.8543 29.9143 29.8743

654 30.3152 30.3253 30.2951

656 29.2857

50
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 8. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISC on

15, 16, and 19 June 1993; BSIXR, PR714 (small aperture) and the SXR on 19 June 1993 (dates and times are given

in PDT).

λ 746 746 746 746 BSIXR 746 PR714 PR714 SXR PR714

[nm] 15 June 15 June 16 June 16 June 19 June 19 June 19 June 19 June 19 June 19 June

1255 1546 1420 1425 1549 1620 1705 1710 1715 1725

658 30.7301 30.7402 30.7503

660 30.9294 31.1314 31.0345 31.0021 30.9713

661 31.0646

662 31.1786 31.1685 31.1482

666 31.6064 31.5963 31.5556

670 32.0000 32.1426 32.0587 32.0422 31.9996 32.0090 32.0090 31.9887

674 32.4267 32.3864 32.4267

678 32.8112 32.8012 32.8412

680 32.9641 33.1867 33.1122 33.0784 33.0116

682 33.2058 33.2058 33.2358

683 32.4052

686 33.5931 33.6329 33.5931

690 33.9582 34.1771 34.0920 34.0574 33.9643 33.9888 34.0187 33.9589

694 34.3424 34.3925 34.3524

698 34.7265 34.7164 34.7365

700 34.9215 35.1189 35.0608 35.0251 34.9335

702 35.1062 35.0451 35.0960

706 35.4583 35.4172 35.4481

710 35.8637 35.9892 35.9759 35.9206 35.8351 35.7990 35.7990 35.8093

714 36.1600 36.1808 36.1496

718 36.5253 36.5461 36.4941

720 36.6333 36.8248 36.7863 36.7476 36.6610

722 36.8723 36.8723 36.8828

726 37.2255 37.2151 37.2255

730 37.4680 37.7114 37.6431 37.6040 37.5323 37.5619 37.5619 37.5516

734 37.8557 37.8965 37.8965

738 38.1889 38.1990 38.1889

740 38.2601 38.5079 38.4609 38.4233 38.3466

742 38.4816 38.4916 38.4816

746 38.7612 38.7513 38.7612

750 38.9944 39.2685 39.1539 39.1352 39.0911 39.0055 39.0055 39.0154

754 39.2280 39.2778 39.2579

758 39.5244 39.5244 39.4843

760 39.4448 39.7114 39.6084 39.5702 39.5372

762 39.8218 39.7415 39.7616

766 40.0622 40.0321 40.0321

770 40.2491 40.5983 40.4601 40.4404 40.3520 40.3162 40.3062 40.3062

772 39.8243

774 40.5832 40.5631 40.5732

778 40.8028 40.8129 40.8735

780 40.8894 41.2262 41.0898 41.0694 40.9802

782 41.0622 41.0723 41.0927

786 41.3073 41.3073 41.3073

790 41.3473 41.7220 41.5943 41.5731 41.4896 41.5244 41.5244 41.5141

794 41.7164 41.7061 41.7164

798 41.8802 41.8596 41.9008

800 41.8781 42.1978 42.0673 42.0673 41.9513

51
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 8. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISC on

15, 16, and 19 June 1993; BSIXR, PR714 (small aperture) and the SXR on 19 June 1993 (dates and times are given

in PDT).

λ 746 746 746 746 BSIXR 746 PR714 PR714 SXR PR714

[nm] 15 June 15 June 16 June 16 June 19 June 19 June 19 June 19 June 19 June 19 June

1255 1546 1420 1425 1549 1620 1705 1710 1715 1725

802 42.0268 42.0062 42.0371

806 42.1943 42.1535 42.1637

810 42.2343 42.5718 42.4876 42.4419 42.3389 42.3310 42.3106 42.3310

814 42.5052 42.4849 42.4545

818 42.6371 42.6371 42.6472

820 42.5696 42.9463 42.7895 42.7661 42.7245

822 42.8081 42.7880 42.7980

826 42.9385 42.9587 42.9587

830 42.9269 43.3314 43.0855 43.0855 43.0860 43.0831 43.1133 43.1033

834 43.2496 43.2192 43.2496

838 43.3742 43.3438 43.3844

840 43.3578 43.6301 43.4149 43.4149 43.4025

842 43.4757 43.4655 43.5062

846 43.5775 43.5673 43.5980

850 43.6093 43.9025 43.6038 43.6038 43.6924 43.6301 43.6818 43.6715

854 43.7110 43.7628 43.7421

858 43.8115 43.8531 43.8219

860 43.8074 44.1101 43.8088 43.7633 43.8980

862 43.9094 43.9409 43.9304

866 44.0383 44.0383 44.0068

870 43.9954 44.2655 43.9426 43.9426 44.1416 44.1299 44.1299 44.1195

874 44.2400 44.2087 44.2087

878 44.2965 44.2861 44.3174

880 44.1750 44.3471 44.0233 44.0020 44.2634

882 44.3651 44.3651 44.3651

886 44.4263 44.3954 44.4057

890 44.2564 44.4155 44.0972 44.0557 44.3611 44.4516 44.3899 44.4414

894 44.4054 44.4156 44.4258

898 44.3615 44.3717 44.3717

900 44.1929 44.3433 44.0103 44.0103 44.2986

902 44.2747 44.2848 44.3052

906 44.2203 44.1899 44.2203

910 44.1242 44.3453 44.0169 44.0169 44.2983 44.1437 44.1437 44.1336

914 44.1125 44.0721 44.0518

918 44.0442 44.0240 44.0037

920 44.1719 44.3762 44.0164 44.0164 44.3338

922 43.9655 43.9756 43.9857

926 43.9264 43.9163 43.9570

930 43.4524 43.6897 43.2975 43.3748 43.6906 43.9001 43.8898 43.9001

934 43.9093 43.8680 43.8165

938 43.7953 43.8367 43.8781

940 43.3325 43.5025 43.1880 43.2652 43.5814

942 43.7919 43.8126 43.8334

946 43.7847 43.7743 43.8158

950 43.3742 43.5726 43.2727 43.3115 43.6117 43.7868 43.7452 43.7868

954 43.7739 43.7009 43.7947

958 43.7797 43.7485 43.6964

52
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 8. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISC on

15, 16, and 19 June 1993; BSIXR, PR714 (small aperture) and the SXR on 19 June 1993 (dates and times are given

in PDT).

λ 746 746 746 746 BSIXR 746 PR714 PR714 SXR PR714

[nm] 15 June 15 June 16 June 16 June 19 June 19 June 19 June 19 June 19 June 19 June

1255 1546 1420 1425 1549 1620 1705 1710 1715 1725

960 43.5945 43.8139 43.4892 43.5483 43.8137

962 43.7270 43.7478 43.7061

966 43.7164 43.7060 43.7164

970 43.6390 43.9286 43.6107 43.6309 43.8425 43.6916 43.7124 43.6916

974 43.6763 43.6763 43.6971

978 43.6282 43.7220 43.6490

980 43.5462 43.8103 43.5576 43.5786 43.7280

982 43.6296 43.6086 43.7030

986 43.6186 43.5872 43.6710

990 43.3930 43.7351 43.4785 43.5005 43.5994 43.5554 43.6077 43.6391

994 43.5965 43.5860 43.5336

998 43.5494 43.5599 43.5074

1000 43.1760 43.5026 43.3572 43.4044 43.4356

1002 43.4768 43.5187 43.5083

1006 43.4015 43.4750 43.4960

1010 43.3974 43.4183 43.4079

1014 43.4001 43.3484 43.3070

1018 43.3262 43.3674 43.1716

1022 43.1825 43.2962 43.1722

1026 43.0788 43.1817 43.1508

1030 42.9116 43.0455 43.1896

1034 42.8436 42.9572 43.0503

1038 42.8142 42.8660 42.8453

1042 42.9956 42.6650 42.5100

1046 42.6060 42.6574 42.5135

1050 42.4227 42.5052 42.4227

1054 42.3302 42.2258 42.3302

1058 42.0753 42.0962 42.2117

1062 42.1545 41.9015 41.7855

1066 42.1452 41.5723 41.5410

1070 41.4140 41.6927 41.5172

53
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 9. GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small aperture)

spectroradiometer on 19 and 21 June 1993 (date and time given in PDT). The spectrum listed for 1127 PDT on 21

June 1993 was measured shortly after the sphere lamps were turned on, without allowing time for warmup.

λ SXR PR714 PR714 SXR PR714 SXR PR714

[nm] 21 June 21 June 21 June 21 June 21 June 21 June 21 June

1120 1127 1343 1352 1448 1451 1600

382 1.7352 1.7807 1.7935 1.8162

386 1.9091 1.9979 1.9878 1.9717

390 2.1665 2.1821 2.1873 2.2195

394 2.3951 2.4664 2.4534 2.4469

398 2.6274 2.7049 2.6554 2.6640

402 2.8663 2.9183 2.8907 2.9141

406 3.0812 3.1697 3.1792 3.1570

410 3.3552 3.4134 3.4145 3.3838

411 3.3631 3.3771 3.3778

414 3.6267 3.6491 3.6609 3.6844

418 3.9120 3.9352 3.9700 3.9648

422 4.2126 4.2974 4.2799 4.2768

426 4.5231 4.6042 4.6125 4.5969

430 4.8175 4.9095 4.9022 4.9032

434 5.1646 5.2202 5.2328 5.2265

438 5.4961 5.5664 5.5706 5.5768

441 5.6631 5.6781 5.6785

442 5.8486 5.9182 5.9383 5.9262

446 6.1918 6.2778 6.2970 6.2606

450 6.5437 6.6358 6.6522 6.6276

454 6.9099 6.9882 6.9820 6.9840

458 7.2619 7.3379 7.3605 7.3543

462 7.6533 7.7338 7.7379 7.7501

466 8.0345 8.1580 8.1470 8.1450

470 8.4512 8.5415 8.5316 8.5555

474 8.8605 8.9837 8.9777 8.9827

478 9.2829 9.4046 9.4252 9.4035

482 9.7182 9.8396 9.8344 9.8417

486 10.1527 10.2743 10.2794 10.2794

487 10.3151 10.3182 10.4033

490 10.6108 10.7518 10.7518 10.7316

494 11.0532 11.1923 11.1923 11.1923

498 11.4508 11.6198 11.5999 11.6297

502 11.9295 12.0701 12.0601 12.0701

506 12.3693 12.5317 12.5215 12.5215

510 12.8516 13.0244 13.0244 13.0244

514 13.3243 13.5070 13.5171 13.4968

518 13.8039 13.9449 13.9549 13.9650

522 14.2722 14.4518 14.4419 14.4518

526 14.7980 14.9468 14.9568 14.9568

530 15.2669 15.4368 15.4368 15.4368

534 15.7342 15.9470 15.9368 15.9368

538 16.2305 16.4757 16.4655 16.4552

542 16.7216 16.9466 16.9466 16.9364

546 17.2062 17.4413 17.4515 17.4311

54
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 9. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small

aperture) spectroradiometer on 19 and 21 June 1993 (date and time given in PDT). The spectrum listed for 1127 PDT

on 21 June 1993 was measured shortly after the sphere lamps were turned on, without allowing time for warmup.

λ SXR PR714 PR714 SXR PR714 SXR PR714

[nm] 21 June 21 June 21 June 21 June 21 June 21 June 21 June

1120 1127 1343 1352 1448 1451 1600

547 17.4880 17.5274 17.5194

550 17.7052 17.9468 17.9468 17.9569

554 18.2516 18.4792 18.4594 18.4495

558 18.7596 18.9578 18.9578 18.9677

562 19.2497 19.4789 19.4689 19.4789

566 19.7410 20.0018 20.0119 19.9717

570 20.2355 20.4791 20.5197 20.4689

574 20.7338 20.9885 21.0191 20.9885

578 21.2378 21.5136 21.5034 21.5136

582 21.7472 22.0217 22.0116 22.0116

586 22.2477 22.5393 22.5192 22.4991

590 22.7312 23.0191 23.0191 22.9894

594 23.2491 23.5155 23.5155 23.5056

598 23.7576 24.0238 24.0041 23.9844

602 24.2307 24.5186 24.4888 24.5086

606 24.6935 25.0233 24.9633 24.9933

610 25.1728 25.4647 25.4647 25.4949

614 25.6647 25.9492 25.9390 25.9187

618 26.0771 26.4139 26.4037 26.4241

622 26.5390 26.8954 26.8954 26.9158

626 27.0250 27.4002 27.3799 27.3799

630 27.5070 27.8803 27.8198 27.8501

634 28.0080 28.3483 28.3383 28.3283

638 28.4860 28.8742 28.8543 28.8344

642 28.9142 29.2226 29.2624 29.2823

646 29.3614 29.6510 29.6810 29.7209

650 29.8044 30.1541 30.1041 30.1541

654 30.1746 30.5663 30.5563 30.5362

658 30.5787 31.0229 31.0431 30.9926

661 31.0331 31.0728 31.0599

662 31.0368 31.4319 31.4623 31.4319

666 31.4845 31.8603 31.8806 31.8705

670 31.8872 32.3135 32.2932 32.3135

674 32.3261 32.6681 32.7083 32.7083

678 32.7413 33.1210 33.1310 33.1310

682 33.1260 33.5154 33.5253 33.5154

686 33.4937 33.9013 33.9311 33.9311

690 33.8792 34.2976 34.3175 34.2976

694 34.2723 34.6429 34.6830 34.6329

698 34.6053 35.0596 35.0394 35.0798

702 34.9942 35.4114 35.4013 35.3809

706 35.3350 35.7666 35.7460 35.7357

710 35.6746 36.1306 36.0995 36.1514

714 35.9833 36.4925 36.5029 36.5029

718 36.3796 36.8374 36.8582 36.8374

55
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 9. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small

aperture) spectroradiometer on 19 and 21 June 1993 (date and time given in PDT). The spectrum listed for 1127 PDT

on 21 June 1993 was measured shortly after the sphere lamps were turned on, without allowing time for warmup.

λ SXR PR714 PR714 SXR PR714 SXR PR714

[nm] 21 June 21 June 21 June 21 June 21 June 21 June 21 June

1120 1127 1343 1352 1448 1451 1600

722 36.7369 37.2058 37.2163 37.1954

726 37.1012 37.5569 37.5569 37.5362

730 37.4182 37.9211 37.9416 37.9211

734 37.7229 38.2541 38.2234 38.2438

738 38.0573 38.5535 38.5737 38.5332

742 38.3417 38.8414 38.8513 38.8114

746 38.5922 39.1190 39.1488 39.1091

750 38.8863 39.3929 39.3929 39.3631

754 39.1384 39.6463 39.6363 39.6064

758 39.3942 39.8947 39.9047 39.8947

762 39.6612 40.1732 40.2134 40.1833

766 39.9117 40.4033 40.4535 40.4334

770 40.1958 40.6775 40.6976 40.7076

772 39.8051 39.8703 39.8574

774 40.4726 40.9454 40.9756 40.9957

778 40.7219 41.3182 41.2475 41.2374

782 40.9605 41.4992 41.5297 41.4585

786 41.1641 41.7163 41.7368 41.7061

790 41.3706 41.9344 41.9549 41.9446

794 41.5519 42.1686 42.1583 42.1480

798 41.7360 42.2716 42.2716 42.2716

802 41.9035 42.4378 42.4275 42.4481

806 42.0313 42.5917 42.5917 42.6019

810 42.1988 42.7782 42.7782 42.7375

814 42.3531 42.9209 42.9514 42.8804

818 42.5362 43.1118 43.1017 43.0613

822 42.6870 43.2522 43.2320 43.2623

826 42.8377 43.4122 43.3920 43.4021

830 43.0026 43.5762 43.5762 43.5259

834 43.1182 43.6943 43.6741 43.6741

838 43.2930 43.8415 43.8618 43.8313

842 43.3636 43.9445 43.9547 43.9445

846 43.4546 44.0181 44.0386 44.0079

850 43.5888 44.1158 44.1055 44.0952

854 43.6385 44.2078 44.1975 44.1768

858 43.6971 44.3004 44.3004 44.2484

862 43.7624 44.3293 44.3503 44.3712

866 43.8285 44.4472 44.4577 44.4891

870 43.9943 44.5889 44.5472 44.5681

874 44.1148 44.6781 44.6468 44.6677

878 44.2339 44.7976 44.7245 44.7559

882 44.2821 44.8321 44.8944 44.8113

886 44.3128 44.9010 44.9216 44.9010

890 44.3075 44.9355 44.9149 44.9149

894 44.3236 44.8657 44.8555 44.8759

56
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 9. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small

aperture) spectroradiometer on 19 and 21 June 1993 (date and time given in PDT). The spectrum listed for 1127 PDT

on 21 June 1993 was measured shortly after the sphere lamps were turned on, without allowing time for warmup.

λ SXR PR714 PR714 SXR PR714 SXR PR714

[nm] 21 June 21 June 21 June 21 June 21 June 21 June 21 June

1120 1127 1343 1352 1448 1451 1600

898 44.2800 44.8605 44.8605 44.8401

902 44.1933 44.7830 44.7728 44.7627

906 44.0986 44.7174 44.6971 44.7072

910 44.0526 44.6195 44.6297 44.6094

914 44.0316 44.5377 44.5579 44.5174

918 43.9632 44.4901 44.5205 44.4698

922 43.9148 44.4521 44.4723 44.4419

926 43.8653 44.4356 44.4254 44.4763

930 43.8694 44.4221 44.4630 44.3914

934 43.8474 44.4347 44.4141 44.3214

938 43.8160 44.3541 44.3541 44.2196

942 43.7816 44.2891 44.2995 44.2062

946 43.8366 44.3350 44.2934 44.1896

950 43.8285 44.3390 44.3390 44.2244

954 43.7634 44.2432 44.2849 44.2119

958 43.7589 44.2901 44.3422 44.2068

962 43.6437 44.2474 44.2890 44.1745

966 43.5291 44.1223 44.2888 44.1327

970 43.6186 44.0982 44.2650 44.1816

974 43.5828 44.0920 44.0920 44.0816

978 43.6803 44.2639 44.1180 44.0555

982 43.6715 44.2485 44.1751 44.1751

986 43.5976 44.1740 44.2579 44.2264

990 43.4717 44.0367 44.1517 44.0890

994 43.4601 43.9954 44.0479 44.0164

998 43.4445 43.9274 44.0114 43.9589

1002 43.3512 44.0946 43.8747 43.9166

1006 43.4015 44.0941 43.9052 43.9157

1010 43.4496 44.0551 43.8881 43.9090

1014 43.2656 43.8035 43.8035 43.8448

1018 43.2953 43.7179 43.8829 43.6870

1022 43.1722 43.6063 43.7717 43.6787

1026 42.9347 43.6447 43.6652 43.6344

1030 43.0558 43.7765 43.6117 43.5294

1034 43.0606 43.6498 43.4534 43.4017

1038 42.6590 43.3833 43.3522 43.3212

1042 42.5616 43.1299 43.3573 43.0473

1046 42.3079 42.8527 43.0275 43.0583

1050 42.2680 42.8250 42.7631 42.8147

1054 42.6122 42.7270 42.6644 42.8941

1058 42.4846 42.5475 42.8204 42.9359

1062 41.7222 42.4919 43.0613 42.7766

1066 41.8327 42.3431 42.2493 42.3639

1070 41.3727 42.0025 41.7547 41.9922

57
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 10. GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small aperture)

spectroradiometer on 22 and 23 June 1993, and the BSIXR and SXR on 22 June 1993 (date and time given in PDT).

The 22 June PR714 scans were made at different lens focus settings. PR714 lens focus settings are given (last row of

header); units are in meters.

λ PR714 PR714 PR714 PR714 PR714 PR714 SXR PR714 BSIXR PR714

[nm] 0918 0919 0919 0920 0920 0921 0926 1013 1430† 1450†

0.7 m 1.0 m 2.0 m 5.0 m ∞ 0.3 m 0.7 m

382 1.7886 1.8370 1.8666 1.7866 1.8449 1.7895 1.7480 1.8063

386 1.9525 1.9555 2.0262 2.0070 2.0353 1.9878 2.0303 1.9848

390 2.1613 2.1342 2.2258 2.2424 2.1706 2.2216 2.2435 2.2008

394 2.4837 2.4632 2.4685 2.4448 2.4567 2.4556 2.4826 2.4599

398 2.6941 2.6758 2.6855 2.6801 2.6780 2.6758 2.6780 2.6758

402 2.9215 2.9322 2.9343 2.9609 2.9385 2.9003 2.9162 2.9152

406 3.1686 3.1781 3.1644 3.1792 3.1929 3.1391 3.1634 3.1760

410 3.4134 3.3976 3.4240 3.4240 3.4092 3.4007 3.4378 3.4177

411 3.3313

412 3.5567

414 3.6844 3.6962 3.7026 3.6790 3.6844 3.6780 3.6673 3.6726

418 3.9817 3.9848 3.9890 3.9774 3.9922 3.9553 3.9690 3.9637

422 4.2902 4.2943 4.2912 4.2912 4.2736 4.2705 4.2943 4.2902

426 4.6188 4.6157 4.6000 4.6146 4.6240 4.5793 4.6250 4.6250

430 4.9200 4.9409 4.9252 4.9220 4.9262 4.8760 4.9252 4.9116

434 5.2328 5.2684 5.2600 5.2391 5.2401 5.2066 5.2317 5.2286

438 5.5706 5.5954 5.5913 5.5882 5.5923 5.5757 5.5861 5.5923

442 5.9293 5.9454 5.9474 5.9514 5.9656 5.9363 5.9383 5.9333

443 5.8771

446 6.3112 6.2880 6.3031 6.3132 6.3224 6.2758 6.3213 6.3031

450 6.6768 6.6512 6.6716 6.6573 6.6768 6.6062 6.6727 6.6430

454 7.0139 7.0345 7.0160 7.0293 7.0201 6.9830 7.0139 7.0201

458 7.3852 7.3831 7.3811 7.4037 7.3903 7.3461 7.3615 7.3708

462 7.7746 7.7654 7.7664 7.7847 7.7929 7.7287 7.7634 7.7542

466 8.1829 8.1819 8.1898 8.2067 8.1868 8.1281 8.1789 8.1460

470 8.5872 8.5733 8.6240 8.6011 8.6150 8.5187 8.6011 8.5733

474 9.0171 9.0110 9.0211 9.0060 9.0191 8.9565 9.0221 8.9918

478 9.4448 9.4479 9.4324 9.4582 9.4592 9.4046 9.4417 9.4066

482 9.8811 9.8883 9.8769 9.8811 9.9039 9.8136 9.8769 9.8479

486 10.3237 10.3237 10.3237 10.3237 10.3443 10.2588 10.3134 10.2959

490 10.7920 10.7719 10.7820 10.8021 10.8021 10.7518 10.7820 10.4941 10.7518

494 11.2222 11.2321 11.2619 11.2719 11.2619 11.1923 11.2321 11.2222

498 11.6794 11.6695 11.7093 11.7291 11.6993 11.6198 11.6595 11.6595

502 12.1404 12.1203 12.1505 12.1505 12.1605 12.0802 12.1103 12.0902

506 12.6129 12.5926 12.6027 12.6230 12.6331 12.5317 12.5824 12.5621

510 13.0854 13.0854 13.0956 13.0956 13.1058 13.0041 13.0549 13.0448

514 13.5679 13.5476 13.5983 13.5983 13.5882 13.4765 13.5476 13.5374

518 14.0456 14.0254 14.0456 14.0758 14.0657 13.9449 14.0254 13.9952

522 14.5417 14.5317 14.5616 14.5417 14.5616 14.4518 14.5317 14.4718

526 15.0560 15.0560 15.0659 15.0560 15.0858 14.9667 15.0362 14.9766

530 15.5568 15.5468 15.5668 15.5768 15.5868 15.4468 15.5368 15.4768

534 16.0280 16.0280 16.0483 16.0686 16.0686 15.9267 16.0078 15.9774

538 16.5369 16.5472 16.5676 16.5676 16.5778 16.4246 16.5165 16.5063

542 17.0489 17.0285 17.0796 17.0694 17.0694 16.9160 17.0285 16.9773

546 17.5435 17.5435 17.5640 17.5742 17.5742 17.4311 17.5435 17.4720

547 17.3073

† Measurements taken on 23 June 1993; all other measurements were taken on 22 June 1993.

58
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 10. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small

aperture) spectroradiometer on 22 and 23 June 1993, and the BSIXR and SXR on 22 June 1993 (date and time given

in PDT). The 22 June PR714 scans were made at different lens focus settings. PR714 lens focus settings are given

(last row of header); units are in meters.

λ PR714 PR714 PR714 PR714 PR714 PR714 SXR PR714 BSIXR PR714

[nm] 0918 0919 0919 0920 0920 0921 0926 1013 1430† 1450†

0.7 m 1.0 m 2.0 m 5.0 m ∞ 0.3 m 0.7 m

550 18.0575 18.0374 18.0575 18.0978 18.0978 17.9468 18.0474 17.9669

554 18.5980 18.5980 18.6178 18.6178 18.6277 18.4792 18.5485 18.4990

558 19.0866 19.1064 19.1064 19.1163 19.1362 18.9677 19.0668 19.0073

562 19.5885 19.6084 19.6283 19.6283 19.6383 19.4689 19.5885 19.5187

566 20.1222 20.1222 20.1523 20.1723 20.1623 19.9818 20.1021 20.0319

570 20.6414 20.6313 20.6414 20.6719 20.6719 20.4892 20.6211 20.5298

574 21.1210 21.1515 21.1617 21.1923 21.1719 20.9987 21.1312 21.0293

578 21.6464 21.6771 21.7077 21.6873 21.7077 21.5238 21.6260 21.5647

582 22.1641 22.1742 22.1946 22.2047 22.2251 22.0319 22.1336 22.0726

586 22.6901 22.6700 22.7202 22.7604 22.7303 22.5091 22.6499 22.5594

589 21.9647

590 23.1979 23.1880 23.2376 23.2376 23.2575 23.0291 23.1880 23.0589

594 23.6831 23.6831 23.7325 23.7522 23.7522 23.5451 23.6634 23.5549

598 24.2111 24.1914 24.2308 24.2505 24.2505 24.0337 24.1815 24.0435

602 24.7469 24.6973 24.7370 24.7767 24.7667 24.5186 24.6973 24.5384

606 25.2031 25.2031 25.1931 25.2231 25.2331 25.0033 25.1532 25.0233

610 25.6660 25.6660 25.7163 25.7063 25.7365 25.5050 25.6459 25.5352

614 26.1320 26.1320 26.2235 26.2133 26.2032 25.9390 26.1117 26.0000

618 26.6078 26.6078 26.6691 26.6486 26.6589 26.4343 26.6180 26.4649

622 27.0889 27.0380 27.1093 27.1296 27.1296 26.8954 27.0787 26.9158

626 27.6030 27.5928 27.6537 27.6131 27.6537 27.3697 27.5523 27.4205

630 28.0721 28.0821 28.0922 28.1326 28.1225 27.8501 28.0519 27.9106

634 28.5585 28.5585 28.5685 28.6286 28.6186 28.3583 28.5385 28.3984

638 29.0534 29.0534 29.1230 29.1230 29.1131 28.8344 29.0235 28.8742

642 29.5011 29.4513 29.5309 29.5409 29.5309 29.2723 29.5011 29.3419

646 29.9307 29.9007 30.0105 29.9906 29.9906 29.7309 29.9207 29.7709

650 30.3739 30.3639 30.4438 30.4338 30.4538 30.1641 30.3039 30.1341

654 30.7974 30.8275 30.8978 30.8476 30.8878 30.5864 30.7773 30.5965

656 29.4180

658 31.2551 31.2046 31.2853 31.2954 31.3156 30.9926 31.2248 31.0632

662 31.6853 31.7055 31.6954 31.7562 31.7663 31.4218 31.6751 31.5535

666 32.1244 32.1345 32.1752 32.1650 32.2259 31.8400 32.1142 31.9111

670 32.5672 32.5672 32.6585 32.6585 32.6687 32.3338 32.5266 32.3642

674 32.9698 33.0201 33.0603 33.1006 33.0704 32.7686 32.9497 32.7385

678 33.4509 33.4608 33.4808 33.5608 33.5508 33.1910 33.4509 33.1610

682 33.8748 33.8248 33.9247 33.9147 33.9247 33.5353 33.8448 33.5653

683 32.4566

686 34.2393 34.2393 34.2990 34.3387 34.3089 33.9609 34.2493 33.9609

690 34.6761 34.6662 34.7060 34.7558 34.7558 34.3474 34.6363 34.3474

694 35.0336 35.0537 35.0737 35.1038 35.1138 34.6930 34.9635 34.7331

698 35.3725 35.4230 35.4836 35.4634 35.5038 35.1000 35.3422 35.1504

702 35.7371 35.7879 35.8592 35.8388 35.8795 35.4725 35.7574 35.4928

706 36.1159 36.1262 36.2289 36.2084 36.2598 35.8180 36.1365 35.8796

710 36.5038 36.4623 36.5763 36.5970 36.6074 36.1825 36.5038 36.2550

714 36.8250 36.8250 36.9081 36.9393 36.9601 36.5340 36.8666 36.5964

718 37.2015 37.2223 37.2639 37.3367 37.3159 36.8686 37.2223 36.9206

† Measurements taken on 23 June 1993; all other measurements were taken on 22 June 1993.

59
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 10. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small

aperture) spectroradiometer on 22 and 23 June 1993, and the BSIXR and SXR on 22 June 1993 (date and time given

in PDT). The 22 June PR714 scans were made at different lens focus settings. PR714 lens focus settings are given

(last row of header); units are in meters.

λ PR714 PR714 PR714 PR714 PR714 PR714 SXR PR714 BSIXR PR714

[nm] 0918 0919 0919 0920 0920 0921 0926 1013 1430† 1450†

0.7 m 1.0 m 2.0 m 5.0 m ∞ 0.3 m 0.7 m

722 37.5602 37.6123 37.6435 37.6748 37.6748 37.2267 37.5602 37.2996

726 37.9296 37.9711 38.0228 38.0125 38.0642 37.5776 37.9607 37.6708

730 38.2597 38.2700 38.3624 38.4239 38.4137 37.9724 38.3008 37.9929

734 38.6218 38.6422 38.7341 38.7546 38.7546 38.2949 38.6422 38.3153

738 38.9687 38.9687 39.0497 39.0700 39.0902 38.6143 38.9586 38.6143

742 39.2710 39.2411 39.3610 39.3610 39.3810 38.8913 39.2610 38.8913

746 39.5265 39.5464 39.5961 39.6457 39.6756 39.1886 39.5265 39.1985

750 39.7803 39.8200 39.8895 39.8995 39.9491 39.4227 39.7604 39.4426

754 40.0745 40.0745 40.1542 40.1741 40.2139 39.6861 40.0446 39.6761

758 40.3551 40.3651 40.4051 40.4452 40.4952 39.9848 40.3251 39.9647

762 40.6452 40.6150 40.7154 40.7456 40.7556 40.2837 40.6452 40.2335

766 40.8849 40.8949 40.9852 41.0253 41.0253 40.5438 40.8749 40.5036

770 41.1794 41.1794 41.2596 41.2797 41.3098 40.8281 41.1492 40.8080

772 39.3340

774 41.4585 41.4283 41.5088 41.5591 41.5692 41.0762 41.4384 41.0360

778 41.6821 41.6922 41.8135 41.8438 41.8539 41.3385 41.7023 41.3182

782 41.9362 41.9566 42.0379 42.0887 42.1090 41.5195 41.9362 41.5805

786 42.2072 42.1970 42.2481 42.3095 42.3402 41.7777 42.2072 41.8288

790 42.4264 42.4469 42.5187 42.5392 42.5699 42.0164 42.4469 42.0369

794 42.6208 42.6413 42.7236 42.7441 42.7955 42.2405 42.6208 42.2303

798 42.7763 42.7763 42.8793 42.8587 42.9102 42.4261 42.7557 42.4158

802 42.9721 42.9310 43.0235 43.0749 43.0955 42.5303 42.9413 42.5611

806 43.1215 43.1012 43.1827 43.2642 43.2744 42.6834 43.1215 42.6936

810 43.2355 43.2660 43.3473 43.4185 43.4185 42.8391 43.2660 42.8798

814 43.4482 43.4482 43.5293 43.6003 43.6206 43.0122 43.4482 43.0426

818 43.6369 43.6369 43.7581 43.7682 43.7884 43.1724 43.6268 43.1724

822 43.7870 43.7769 43.9081 43.9384 43.9687 43.3733 43.7870 43.3228

826 43.9563 43.9865 44.0974 44.1175 44.1478 43.5532 43.9462 43.4928

830 44.1600 44.1398 44.2606 44.2707 44.3310 43.7473 44.1298 43.6568

834 44.2704 44.2805 44.3917 44.4321 44.4422 43.8661 44.3209 43.7853

838 44.4306 44.4306 44.5221 44.6033 44.5932 44.0040 44.4205 43.9735

842 44.5253 44.5253 44.5967 44.6782 44.6782 44.1075 44.4948 44.0464

846 44.6534 44.6226 44.7149 44.7661 44.7456 44.1820 44.6329 44.1411

850 44.7359 44.7256 44.8496 44.8806 44.9012 44.2502 44.6739 44.2502

854 44.7978 44.8185 44.9324 44.9531 44.9945 44.3424 44.7564 44.3217

858 44.9037 44.9141 45.0701 45.0701 45.1117 44.4772 44.8725 44.4460

862 44.9171 44.9486 45.1060 45.1585 45.1165 44.4867 44.9486 44.5392

866 45.0973 45.0658 45.2021 45.2441 45.2441 44.6464 45.0868 44.5940

870 45.2149 45.2253 45.3297 45.3818 45.4027 44.7872 45.2045 44.6515

874 45.3562 45.3353 45.4501 45.4709 45.5126 44.8867 45.3040 44.8033

878 45.4762 45.4658 45.5806 45.6224 45.6224 44.9855 45.4031 44.9333

882 45.5170 45.5793 45.6208 45.7038 45.6831 45.0293 45.5274 44.9463

886 45.5821 45.6131 45.6853 45.7369 45.7885 45.0661 45.5408 45.0042

890 45.6149 45.6355 45.7076 45.7693 45.7899 45.1414 45.5635 45.0384

894 45.5818 45.5715 45.6943 45.7966 45.7557 45.0908 45.5613 44.9782

† Measurements taken on 23 June 1993; all other measurements were taken on 22 June 1993.

60
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 10. (cont.) GSFC sphere (16-lamps) spectral radiance [μWcm−2 nm−1sr−1] measured with the PR714 (small

aperture) spectroradiometer on 22 and 23 June 1993, and the BSIXR and SXR on 22 June 1993 (date and time given

in PDT). The 22 June PR714 scans were made at different lens focus settings. PR714 lens focus settings are given

(last row of header); units are in meters.

λ PR714 PR714 PR714 PR714 PR714 PR714 SXR PR714 BSIXR PR714

[nm] 0918 0919 0919 0920 0920 0921 0926 1013 1430† 1450†

0.7 m 1.0 m 2.0 m 5.0 m ∞ 0.3 m 0.7 m

898 45.6040 45.5836 45.7160 45.7669 45.7567 45.1151 45.5530 44.9522

902 45.5048 45.4743 45.5963 45.6776 45.6878 44.9762 45.4845 44.9355

906 45.4275 45.4174 45.5188 45.6000 45.6203 44.9304 45.4478 44.8391

910 45.3587 45.3384 45.4397 45.5308 45.5206 44.8220 45.3283 44.7411

914 45.3373 45.2968 45.3981 45.4487 45.4487 44.8211 45.2361 44.6693

918 45.2500 45.2905 45.4121 45.3513 45.4019 44.7535 45.1790 44.6522

922 45.2022 45.2225 45.3340 45.3340 45.3137 44.7359 45.1617 44.5737

926 45.2196 45.2196 45.3112 45.3621 45.3825 44.6901 45.1687 44.5985

930 45.1590 45.1386 45.3126 45.2716 45.3842 44.6473 45.1897 44.5654

934 45.1044 45.0528 45.2692 45.2589 45.3207 44.5995 45.1765 44.5892

938 45.0992 45.0475 45.1923 45.3269 45.2958 44.5714 45.2130 44.4990

942 45.0245 45.0866 45.1073 45.2213 45.2213 44.5066 45.1177 44.4134

946 45.0514 45.1449 45.0929 45.1864 45.2902 44.5738 45.0722 44.5011

950 45.0995 45.0995 45.1204 45.2245 45.3079 44.6307 45.0370 44.5786

954 45.0046 44.9837 45.2340 45.1193 45.3175 44.5248 45.0463 44.4310

958 44.9880 44.9984 45.2067 45.2276 45.2172 44.5297 45.0088 44.4776

962 44.9760 44.9760 45.0801 45.1946 45.1529 44.4451 44.9760 44.3515

966 44.9548 44.9340 44.9652 45.1421 45.0692 44.3824 44.9548 44.3200

970 44.9322 45.0364 44.9635 45.1407 45.1094 44.4109 44.9322 44.3692

974 44.8817 44.9025 45.0065 45.0688 45.1208 44.2998 44.8817 44.2583

978 44.9935 44.9935 45.0560 45.1082 45.2124 44.4203 44.9101 44.3160

982 44.9933 45.0668 45.1926 45.1717 45.2241 44.5003 44.9933 44.4268

986 44.9601 45.0229 45.1173 45.1592 45.1382 44.4465 44.8343 44.3417

990 44.8841 44.9260 45.0201 45.0620 45.1248 44.2773 44.8004 44.2668

994 44.8457 44.8038 44.9507 45.0242 45.0872 44.2054 44.7933 44.1949

998 44.8198 44.8933 44.9668 45.0928 45.1033 44.3264 44.7673 44.2004

1002 44.6915 44.7648 44.8067 44.9324 44.9324 44.2936 44.5973 44.0946

1006 44.8182 44.8391 44.8811 44.9756 44.9336 44.2200 44.6922 44.2410

1010 44.8485 44.8485 44.8798 44.8903 44.9425 44.1804 44.7546 44.2013

1014 44.6206 44.5999 44.9309 44.7033 44.9205 44.0310 44.6102 44.0207

1018 44.5220 44.6354 44.7900 44.7591 44.8312 44.2024 44.5117 43.7489

1022 44.6089 44.6606 44.6192 44.7019 44.6606 44.0508 44.4228 44.0094

1026 44.5706 44.4781 44.6221 44.7353 44.5706 43.9739 44.5295 43.8299

1030 44.5075 44.3839 44.6928 44.8163 44.7340 43.9412 44.7134 43.9206

1034 44.3216 44.2493 44.5594 44.6110 44.7144 43.6188 44.2286 43.7325

1038 44.2421 44.0351 44.4904 44.4904 44.3559 43.7144 44.2007 43.6730

1042 44.0909 44.1529 43.9152 43.9876 44.2252 43.5019 44.2046 42.8716

1046 43.8601 44.0040 43.8601 43.8087 44.1170 43.5311 43.9115 42.7911

1050 43.8564 43.9595 43.8152 43.9595 43.9802 43.4645 43.3201 42.7940

1054 43.9905 43.8338 43.8756 43.9383 44.0740 43.4162 43.4371 43.2178

1058 43.6180 43.2297 43.6180 43.9014 43.9959 42.8834 43.5761 43.0933

1062 43.0613 43.2195 43.5358 43.9259 43.5779 42.8610 43.4092 43.0297

1066 43.1972 42.9889 43.3847 43.4368 43.4368 42.3118 43.3014 42.6660

1070 42.6530 43.1589 42.9627 43.2312 43.1383 42.1264 43.0040 42.1367

† Measurements taken on 23 June 1993; all other measurements were taken on 22 June 1993.

61
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

(Tables 9, 10, and 12). In general, the SXR radiances on

all days are in closer agreement with the 746/ISIC reading

of 19 June than they are with concurrent measurements

made with the PR714.

The radiance levels of the GSFC sphere may be varied

by selecting the number of lamps with which it is illuminated. Variations in radiance scales for 1–16 lamps were

measured with the 746/ISIC on 15 June 1993 (Table 11),

and with the PR714 and SXR on 22 June 1993 (Tables 12

and 13). The two sets of radiance scales for the 16 levels of

illumination are illustrated in Fig. 21. As with the other

PR714 measurements on 22 June 1993, the measured radiance levels of the GSFC sphere were about 3% higher

than those measured with the 746/ISIC on 15 June 1993.

PR714 radiances also exceeded the SXR radiances at all

wavelengths by amounts ranging from 1–5%.

3.2.2 The BSI Sphere

The spectral radiance of the BSI sphere, with one lamp

and open aperture, was measured with the 746/ISIC (F269)

on 17 June 1993, the PR714 on 24 June, the BSIXR on

17 and 23 June, and the SXR on 23 June (Table 14 and

Fig. 22). The 17 June BSIXR radiances exceeded the 17

June 746/ISIC (F269) scale of this sphere by 0.5–2.5%,

but on 23 June, the BSIXR radiances indicate decreases

in spectral radiance to within less than 1% of the 17 June

746/ISIC (F269) scale. The PR714 radiance spectra for

the BSI sphere on 24 June exceeded the 17 June 746/ISIC

(F269) scale by approximately 2% at 400 nm, increasing to

4% at 900 nm, and then decreasing to 2% (1,000 nm). SXR

radiances of the BSI sphere on 23 June exceeded 746/ISIC

(17 June) radiances by 3.5–6.5% and PR714 (24 June) radiances by approximately 3.5–7%.

3.2.3 The CHORS Sphere

At the outset of SIRREX-2, the CHORS sphere was

configured with four 125 Wtungsten-halogen lamps. Initial measurements with the 746/ISIC indicated that the

sphere’s radiance levels in this configuration were undesirably low. Therefore, four new 275 Wlamps were installed on 17 June, and the CHORS sphere was turned

on to season the lamps overnight. The spectral radiance of

the sphere was measured at approximately hourly intervals

with the BSIXR on the afternoon of 18 June 1993, with

a follow-up BSIXR measurement at 1100 PDT on 19 June

1993. In addition to the BSIXR measurements on 18–19

June, the radiance scale of the CHORS sphere was measured with the PR714 on 18, 19, and 23 June 1993; and

the SXR on 18 and 19 June, and was calibrated relative to

lamp F269 with the 746/ISIC on 19 June 1993.

Calibrated spectral radiances for the CHORS sphere, as

measured with these instruments, are listed in Tables 15–

16. Figure 23 compares all of the above measurements

of the CHORS sphere radiance scale. The 746/ISIC and

PR714 values all show repeatable variations in the spectral

radiance with wavelength (Fig. 23, top panel), which represent undesirable line structures. This structure has been

smoothed differently by the two radiometers, resulting in

very large spikes in the relative differences (Fig. 23, bottom panel) as referenced to the 746/ISIC measurements.

The analysis is compounded by the fact that the PR714

calibration factors (Fig. 18 and Table 6) depend strongly

on wavelength.

The BSIXR (18–19 June) and the 746/ISIC (19 June)

measurements of the CHORS sphere are compared separately in Fig. 24, and agree within 2%. Again, this disagreement is possibly attributable to the different spectral resolution of the two instruments when attempting to

measure a source with structure. In Fig. 25, the BSIXR,

SXR, and PR714 measurements from 18 June 1993, and

the 746/ISIC spectrum of 19 June 1993 are compared.

The BSIXR and PR714 data agree within 1–2% on 18

June; both of these instruments indicate lower overall spectral radiance levels, by up to 3% (neglecting spikes associated with the line resolution mismatch) from the 746/ISIC

(F269) radiance scale of 19 June 1993. Figure 26 illustrates

the same comparison for BSIXR, SXR, and PR714 data on

19 June, with almost the same results. Figure 27 compares

the PR714 spectral radiance measurements of the CHORS

sphere on 23 June with its 746/ISIC (F269) scale of 19

June. In this subset of the data, within-day variability between PR714 radiance measurements is significantly larger

than on the previous days (3% versus 1% previously), and

the apparent radiance of the sphere is shifted 5–7% higher.

It was observed from the log sheets that the measurements

on 23 June correspond to the closest distance between the

PR714 and CHORS sphere, and the largest viewing angle (20◦ from normal). These variations of response with

either distance or angle would indicate either out-of-field

stray light sensitivity of the PR714, or inhomogeneity in

the sphere. However, measurements of this sphere at two

angles on 18 June agreed within less than 1%. Variation of

PR714 sensitivity with room temperature could be another

possible explanation.

Measurements of the CHORS sphere with the SXR on

19 June exceed 746/ISIC (19 June) measurements by 0.25–

2% and with the PR714 (18–19 June) measurements by

0.25–4%.

3.2.4 The UCSB Sphere

Spectral radiance of the UCSB sphere, illuminated with

FEL lamp F303 at 50 cm through a 50.8 cm entrance aperture, was measured with the 746/ISIC (F269), the PR714,

and the SXR on 21 June 1993. The spectral radiance of

the sphere with a 2.54 cm entrance aperture was also measured on this day with the PR714. The results of these

measurements are listed in Table 17 and are illustrated

in Fig. 28. Between wavelengths of 430–1,000 nm, the

PR714 radiances are less than those measured with the

746/ISIC (F269) by approximately 5% (430 nm) to 10%

62
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 21. Spectral radiance (μWcm−2 nm−1 sr−1) of the GSFC sphere, with 1–16 lamps, measured with the

PR714 (23 June 1993) (solid curves of increasing magnitude) and with the 746/ISIC (15 June 1993) at 50 nm

intervals.

63
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 11. GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 1–16 lamps, measured

with the 746/ISIC on 15 June 1993 (date and time are given in PDT). (Top line of the header indicates the number of

lamps turned on at one time.)

λ 123 4 5 6 7 8

[nm] 1347 1344 1341 1338 1333 1331 1329 1327

400 0.1302 0.2622 0.3807 0.5241 0.8146 0.9980 1.1605 1.3212

450 0.3891 0.7999 1.1714 1.5863 1.9537 2.3931 2.7969 3.1947

500 0.7011 1.4371 2.1297 2.8780 3.5495 4.3055 5.0499 5.7560

550 1.0710 2.1979 3.2416 4.3751 5.3980 6.5385 7.6651 8.7398

600 1.4598 2.9706 4.3986 5.9253 7.3437 8.8673 10.4004 11.8602

650 1.8066 3.6971 5.4857 7.3672 9.1379 11.0313 12.8829 14.7104

700 2.1221 4.3249 6.4302 8.6162 10.7115 12.8941 15.1103 17.2257

750 2.3820 4.8417 7.2060 9.6445 12.0089 14.4685 16.9387 19.2678

800 2.5669 5.2045 7.7506 10.3716 12.9135 15.5845 18.1680 20.7515

Table 11. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 1–16 lamps,

measured with the 746/ISIC on 15 June 1993 (date and time are given in PDT). (Top line of the header indicates the

number of lamps turned on at one time.)

λ 9 10 11 12 13 14 15 16

[nm] 1347 1344 1341 1338 1333 1331 1329 1327

400 1.4913 1.6954 1.8826 2.0357 2.2114 2.3740 2.5384 2.7161

450 3.6102 4.0724 4.5171 4.8916 5.3129 5.7224 6.1203 6.5592

500 6.5081 7.3408 8.1198 8.7990 9.5549 10.2917 11.0131 11.8036

550 9.8872 11.1313 12.3097 13.3396 14.4454 15.5513 16.6572 17.8322

600 13.3869 15.0444 16.6381 18.0086 19.5386 21.0366 22.5347 24.0965

650 16.5979 18.6352 20.6126 22.3203 24.2078 26.0953 27.9528 29.8403

700 19.4083 21.8259 24.0757 26.1239 28.3401 30.5563 32.7053 34.9215

750 21.7380 24.4200 26.8902 29.2193 31.6895 34.1598 36.5594 39.0297

800 23.3351 26.1686 28.9188 31.3773 34.0442 36.6694 39.2529 41.8781

64
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 12. GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 1–8 lamps, measured with

the PR714 (small aperture) spectroradiometer and the SXR on 22 June 1993 (date and time are given in PDT). (The

top line of the table header indicates the number of lamps turned on at one time.)

λ 1234456788

[nm] PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1013 1057 1056 1055 1112 1044 1043 1042 1042 1100

382 0.1028 0.2144 0.3191 0.4273 0.5246 0.6433 0.7885 0.8629

386 0.1129 0.2381 0.3560 0.4857 0.6001 0.7301 0.8559 0.9519

390 0.1294 0.2661 0.3947 0.5280 0.6555 0.7998 0.9245 1.0645

394 0.1450 0.3006 0.4327 0.5957 0.7213 0.8852 1.0440 1.1830

398 0.1552 0.3233 0.4706 0.6431 0.7946 0.9543 1.1377 1.2809

402 0.1664 0.3479 0.5112 0.6990 0.8723 1.0460 1.2439 1.3885

406 0.1820 0.3780 0.5533 0.7567 0.9417 1.1387 1.3368 1.5253

410 0.1975 0.4099 0.5982 0.8151 1.0019 1.2271 1.4494 1.6580

411 0.8031 1.6066

414 0.2136 0.4444 0.6516 0.8890 1.0884 1.3215 1.5663 1.7738

418 0.2311 0.4780 0.7044 0.9561 1.1717 1.4345 1.6879 1.9159

422 0.2485 0.5165 0.7531 1.0301 1.2711 1.5359 1.8183 2.0686

426 0.2679 0.5584 0.8068 1.1092 1.3649 1.6539 1.9512 2.2330

430 0.2863 0.5933 0.8653 1.1840 1.4517 1.7686 2.0866 2.3784

434 0.3053 0.6306 0.9242 1.2584 1.5499 1.8949 2.2169 2.5273

438 0.3234 0.6725 0.9835 1.3394 1.6507 2.0148 2.3602 2.7015

441 1.3470 2.6954

442 0.3450 0.7166 1.0460 1.4294 1.7643 2.1405 2.5117 2.8759

446 0.3685 0.7628 1.1131 1.5168 1.8680 2.2717 2.6714 3.0509

450 0.3907 0.8054 1.1735 1.6001 1.9766 2.3940 2.8217 3.2176

454 0.4120 0.8513 1.2397 1.6907 2.0891 2.5288 2.9787 3.3813

458 0.4315 0.8908 1.3059 1.7774 2.1997 2.6621 3.1306 3.5611

462 0.4532 0.9369 1.3717 1.8690 2.3133 2.8025 3.3018 3.7533

466 0.4774 0.9870 1.4444 1.9681 2.4320 2.9516 3.4702 3.9650

470 0.5027 1.0364 1.5219 2.0738 2.5543 3.0894 3.6414 4.1586

474 0.5308 1.0929 1.6020 2.1778 2.6818 3.2545 3.8353 4.3565

478 0.5566 1.1472 1.6770 2.2790 2.8150 3.4056 4.0241 4.5806

482 0.5810 1.1976 1.7498 2.3839 2.9453 3.5649 4.2094 4.7833

486 0.6042 1.2477 1.8298 2.4872 3.0734 3.7194 4.3881 4.9867

487 2.4582 4.9198

490 0.6332 1.3047 1.9138 2.6014 3.2205 3.8890 4.5876 5.2259

494 0.6616 1.3628 1.9959 2.7166 3.3577 4.0585 4.7841 5.4500

498 0.6876 1.4184 2.0794 2.8299 3.4899 4.2225 4.9789 5.6598

502 0.7190 1.4771 2.1600 2.9382 3.6291 4.3952 5.1645 5.8824

506 0.7460 1.5312 2.2435 3.0482 3.7676 4.5571 5.3627 6.1126

510 0.7736 1.5902 2.3304 3.1631 3.9094 4.7360 5.5595 6.3475

514 0.8039 1.6511 2.4193 3.2890 4.0633 4.9076 5.7833 6.5840

518 0.8288 1.7046 2.5000 3.3991 4.1935 5.0705 5.9797 6.8164

522 0.8574 1.7616 2.5880 3.5132 4.3425 5.2578 6.1979 7.0483

526 0.8885 1.8272 2.6847 3.6454 4.5049 5.4497 6.4115 7.3047

530 0.9203 1.8906 2.7764 3.7652 4.6571 5.6338 6.6266 7.5484

534 0.9512 1.9513 2.8662 3.8864 4.8054 5.8134 6.8398 7.7962

538 0.9853 2.0153 2.9622 4.0203 4.9682 6.0091 7.0642 8.0448

542 1.0118 2.0721 3.0467 4.1380 5.1096 6.1783 7.2716 8.2831

546 1.0387 2.1306 3.1335 4.2540 5.2631 6.3631 7.4918 8.5295

65
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 12. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 1–8 lamps,

measured with the PR714 (small aperture) spectroradiometer and the SXR on 22 June 1993 (date and time are given

in PDT). (The top line of the table header indicates the number of lamps turned on at one time.)

λ 12344 56788

[nm] PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1013 1057 1056 1055 1112 1044 1043 1042 1042 1100

547 4.2152 8.4261

550 1.0700 2.1933 3.2240 4.3765 5.4243 6.5496 7.7162 8.7801

554 1.0997 2.2567 3.3197 4.5075 5.5834 6.7325 7.9341 9.0347

558 1.1337 2.3229 3.4179 4.6369 5.7319 6.9290 8.1618 9.2807

562 1.1687 2.3903 3.5102 4.7666 5.8955 7.1160 8.3754 9.5332

566 1.1997 2.4546 3.6102 4.8971 6.0527 7.3176 8.5986 9.7933

570 1.2300 2.5168 3.7041 5.0223 6.2066 7.4945 8.8188 10.0487

574 1.2603 2.5838 3.7983 5.1432 6.3638 7.6873 9.0383 10.3007

578 1.2892 2.6417 3.8870 5.2681 6.5236 7.8802 9.2684 10.5525

582 1.3166 2.6983 3.9702 5.3824 6.6706 8.0614 9.4736 10.7973

586 1.3481 2.7576 4.0595 5.5092 6.8231 8.2366 9.6973 11.0485

590 1.3803 2.8263 4.1550 5.6436 6.9872 8.4321 9.9217 11.3010

594 1.4125 2.8911 4.2602 5.7684 7.1434 8.6200 10.1499 11.5506

598 1.4442 2.9544 4.3513 5.8931 7.3038 8.8160 10.3607 11.7901

602 1.4771 3.0187 4.4441 6.0195 7.4528 9.0044 10.5817 12.0508

606 1.5060 3.0759 4.5310 6.1329 7.5939 9.1669 10.7828 12.2718

610 1.5400 3.1433 4.6300 6.2615 7.7602 9.3495 11.0012 12.5310

614 1.5708 3.2035 4.7184 6.3857 7.9087 9.5353 11.2067 12.7612

618 1.5932 3.2578 4.7939 6.4943 8.0405 9.7052 11.4106 12.9926

622 1.6202 3.3138 4.8709 6.6032 8.1806 9.8712 11.6095 13.2186

626 1.6499 3.3708 4.9598 6.7202 8.3336 10.0454 11.8139 13.4567

630 1.6791 3.4308 5.0544 6.8444 8.4791 10.2319 12.0280 13.7030

634 1.7097 3.4935 5.1411 6.9640 8.6336 10.4304 12.2422 13.9239

638 1.7428 3.5523 5.2344 7.0777 8.7817 10.6101 12.4514 14.1833

642 1.7705 3.6056 5.3213 7.1893 8.9160 10.7521 12.6518 14.4124

646 1.7996 3.6592 5.4079 7.2994 9.0571 10.9356 12.8431 14.6308

650 1.8304 3.7238 5.4843 7.4156 9.1961 11.0905 13.0288 14.8372

654 1.8553 3.7829 5.5809 7.5276 9.3346 11.2602 13.2089 15.0471

658 1.8828 3.8352 5.6463 7.6321 9.4633 11.4077 13.4066 15.2843

661 7.5334 15.0438

662 1.9100 3.8880 5.7281 7.7384 9.6039 11.5818 13.5982 15.5032

666 1.9307 3.9356 5.8033 7.8508 9.7379 11.7407 13.8024 15.7118

670 1.9496 3.9844 5.8802 7.9464 9.8696 11.9044 13.9849 15.9233

674 1.9754 4.0302 5.9653 8.0544 9.9945 12.0594 14.1615 16.1329

678 2.0059 4.0867 6.0465 8.1713 10.1442 12.2130 14.3518 16.3606

682 2.0347 4.1472 6.1260 8.2765 10.2633 12.3499 14.5463 16.5630

686 2.0589 4.1894 6.1887 8.3769 10.3792 12.5166 14.7038 16.7518

690 2.0859 4.2456 6.2708 8.4733 10.5194 12.6711 14.8925 16.9645

694 2.1068 4.2918 6.3375 8.5545 10.6393 12.7932 15.0574 17.1512

698 2.1330 4.3408 6.4082 8.6644 10.7612 12.9619 15.2130 17.3228

702 2.1562 4.3898 6.4840 8.7572 10.8677 13.0961 15.3755 17.5226

706 2.1803 4.4325 6.5502 8.8487 10.9838 13.2237 15.5355 17.7035

710 2.2035 4.4775 6.6208 8.9477 11.1004 13.3702 15.7229 17.8891

714 2.2278 4.5273 6.6927 9.0338 11.2117 13.4977 15.8771 18.0384

718 2.2460 4.5659 6.7422 9.1058 11.3186 13.6281 16.0208 18.2574

66
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 12. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 1–8 lamps,

measured with the PR714 (small aperture) spectroradiometer and the SXR on 22 June 1993 (date and time are given

in PDT). (The top line of the table header indicates the number of lamps turned on at one time.)

λ 123 445 6 7 8 8

[nm] PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1013 1057 1056 1055 1112 1044 1043 1042 1042 1100

722 2.2657 4.6054 6.8106 9.1972 11.4327 13.7776 16.1851 18.4257

726 2.2915 4.6586 6.8932 9.3038 11.5560 13.9169 16.3502 18.5972

730 2.3132 4.7034 6.9571 9.3946 11.6688 14.0395 16.4923 18.7912

734 2.3300 4.7386 7.0083 9.4700 11.7673 14.1678 16.6397 18.9585

738 2.3505 4.7820 7.0707 9.5538 11.8688 14.2892 16.7804 19.1198

742 2.3702 4.8234 7.1307 9.6259 11.9512 14.3994 16.9175 19.2658

746 2.3903 4.8660 7.1887 9.7022 12.0458 14.5106 17.0251 19.4104

750 2.4077 4.8948 7.2389 9.7668 12.1278 14.6109 17.1537 19.5375

754 2.4230 4.9217 7.2819 9.8314 12.1996 14.6993 17.2687 19.6488

758 2.4341 4.9433 7.3174 9.8936 12.2707 14.7929 17.3751 19.7872

762 2.4540 4.9812 7.3699 9.9605 12.3703 14.8905 17.5011 19.9410

766 2.4752 5.0206 7.4325 10.0331 12.4611 14.9995 17.6282 20.0762

770 2.4870 5.0493 7.4791 10.0966 12.5355 15.1048 17.7343 20.2133

772 9.6859 19.3340

774 2.5030 5.0825 7.5332 10.1609 12.6257 15.2112 17.8470 20.3419

778 2.5258 5.1284 7.5946 10.2588 12.7351 15.3225 18.0009 20.4873

782 2.5410 5.1572 7.6331 10.2960 12.7963 15.4085 18.0917 20.6022

786 2.5557 5.1902 7.6867 10.3703 12.8759 15.4941 18.1940 20.7406

790 2.5749 5.2287 7.7360 10.4349 12.9668 15.6011 18.3175 20.8493

794 2.5868 5.2498 7.7719 10.4831 13.0216 15.6732 18.4276 20.9661

798 2.5915 5.2603 7.7972 10.5164 13.0708 15.7179 18.4475 21.0225

802 2.6048 5.2888 7.8371 10.5735 13.1321 15.7934 18.5473 21.1264

806 2.6217 5.3199 7.8734 10.6173 13.1953 15.8649 18.6160 21.2041

810 2.6334 5.3369 7.8960 10.6514 13.2227 15.9160 18.6805 21.2925

814 2.6393 5.3547 7.9271 10.6871 13.2829 15.9800 18.7481 21.3641

818 2.6560 5.3837 7.9679 10.7350 13.3405 16.0470 18.8444 21.4599

822 2.6611 5.3929 7.9915 10.7777 13.3914 16.0959 18.9014 21.5252

826 2.6654 5.4023 8.0133 10.8027 13.4328 16.1536 18.9651 21.6053

830 2.6780 5.4335 8.0490 10.8588 13.4956 16.2430 19.0508 21.7076

834 2.6926 5.4550 8.0839 10.9059 13.5338 16.2830 19.1232 21.7612

838 2.7020 5.4639 8.1009 10.9299 13.5811 16.3339 19.1781 21.8395

842 2.7109 5.4900 8.1275 10.9555 13.6053 16.3874 19.2206 21.8907

846 2.7183 5.5043 8.1540 10.9943 13.6378 16.4248 19.2835 21.9578

850 2.7292 5.5256 8.1773 11.0160 13.6925 16.4621 19.3349 21.9907

854 2.7357 5.5345 8.2029 11.0442 13.7147 16.5094 19.3558 22.0573

858 2.7450 5.5513 8.2246 11.0777 13.7613 16.5385 19.3990 22.1034

862 2.7450 5.5614 8.2371 11.0849 13.7827 16.5749 19.4616 22.1804

866 2.7440 5.5551 8.2257 11.0934 13.7986 16.6087 19.4817 22.1869

870 2.7490 5.5710 8.2616 11.1420 13.8545 16.6504 19.5403 22.2632

874 2.7643 5.5986 8.2983 11.1721 13.9052 16.7008 19.5904 22.3130

878 2.7749 5.6177 8.3206 11.2125 13.9268 16.7352 19.6479 22.3936

882 2.7802 5.6248 8.3303 11.2184 13.9685 16.7705 19.6867 22.4057

886 2.7750 5.6232 8.3301 11.2072 13.9522 16.7901 19.6900 22.4247

890 2.7744 5.6208 8.3365 11.2107 13.9490 16.8006 19.7037 22.4523

894 2.7762 5.6210 8.3328 11.2113 13.9425 16.7863 19.7119 22.4328

67
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 12. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 1–8 lamps,

measured with the PR714 (small aperture) spectroradiometer and the SXR on 22 June 1993 (date and time are given

in PDT). (The top line of the table header indicates the number of lamps turned on at one time.)

λ 1 2 3 445 6 7 88

[nm] PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1013 1057 1056 1055 1112 1044 1043 1042 1042 1100

898 2.7762 5.6195 8.3336 11.2228 13.9521 16.8036 19.7060 22.4252

902 2.7693 5.6169 8.3171 11.2135 13.9483 16.7542 19.6618 22.3762

906 2.7664 5.5988 8.3044 11.1996 13.9184 16.7183 19.6197 22.3587

910 2.7630 5.5929 8.2921 11.1675 13.8911 16.7159 19.6014 22.3351

914 2.7583 5.5864 8.2840 11.1648 13.8674 16.6814 19.5763 22.3195

918 2.7559 5.5787 8.2718 11.1453 13.8405 16.6673 19.5651 22.2602

922 2.7584 5.5684 8.2690 11.1409 13.8476 16.6455 19.5244 22.2615

926 2.7523 5.5667 8.2609 11.1191 13.8378 16.6481 19.5093 22.2585

930 2.7482 5.5528 8.2365 11.1260 13.8384 16.6224 19.5191 22.2110

934 2.7497 5.5489 8.2441 11.1164 13.8260 16.6282 19.5438 22.2225

938 2.7486 5.5562 8.2396 11.1454 13.8568 16.6199 19.5382 22.2288

942 2.7406 5.5434 8.2219 11.1033 13.8170 16.6136 19.4930 22.1963

946 2.7432 5.5465 8.2316 11.0993 13.8404 16.6126 19.5095 22.2090

950 2.7462 5.5518 8.2563 11.1160 13.8247 16.6376 19.5129 22.2112

954 2.7441 5.5486 8.2364 11.0973 13.7986 16.5938 19.4724 22.2155

958 2.7468 5.5467 8.2320 11.1038 13.8016 16.5932 19.4993 22.1867

962 2.7458 5.5603 8.2520 11.1165 13.8019 16.6019 19.4955 22.1705

966 2.7420 5.5434 8.2292 11.0826 13.7778 16.5667 19.4492 22.1444

970 2.7366 5.5462 8.2129 11.0715 13.7820 16.5863 19.4741 22.1638

974 2.7320 5.5315 8.2198 11.0568 13.7690 16.5644 19.4325 22.1447

978 2.7380 5.5332 8.2295 11.0686 13.7784 16.5612 19.4482 22.0955

982 2.7432 5.5473 8.2517 11.0988 13.7949 16.5853 19.4282 22.1977

986 2.7437 5.5409 8.2311 11.0671 13.7919 16.5797 19.4513 22.1761

990 2.7401 5.5430 8.2172 11.0693 13.7687 16.5621 19.4393 22.1073

994 2.7462 5.5480 8.2102 11.0645 13.7833 16.5442 19.4625 22.0975

998 2.7381 5.5361 8.2374 11.0658 13.7326 16.5358 19.3810 22.1002

1002 2.7246 5.5236 8.2053 11.0158 13.7383 16.4923 19.3824 22.0421

1006 2.7189 5.5039 8.1871 10.9973 13.7361 16.5064 19.3817 22.0576

1010 2.7122 5.4871 8.1721 10.9929 13.7176 16.4737 19.3446 22.0171

1014 2.7068 5.4902 8.1504 10.9638 13.6427 16.3836 19.3004 21.9069

1018 2.7194 5.4841 8.1529 10.9991 13.6792 16.4316 19.2664 21.9260

1022 2.7100 5.5007 8.1156 10.9455 13.6741 16.4338 19.2244 21.9220

1026 2.7183 5.5014 8.1641 10.9575 13.6531 16.4105 19.2605 21.9355

1030 2.7160 5.5122 8.1479 10.9544 13.6312 16.3390 19.2217 21.8985

1034 2.7029 5.4833 8.1129 10.9254 13.5714 16.3725 19.1633 21.8197

1038 2.6943 5.4351 8.0621 10.8639 13.5541 16.3166 19.0791 21.7486

1042 2.6783 5.4248 8.0752 10.8393 13.4536 16.2745 19.0437 21.6890

1046 2.6612 5.3903 8.0206 10.7928 13.4756 16.1379 18.9440 21.5446

1050 2.6642 5.3748 8.0018 10.7578 13.4808 16.1522 18.9989 21.6497

1054 2.6751 5.4035 8.0442 10.7757 13.4801 16.0905 18.9724 21.6245

1058 2.6689 5.3473 7.9763 10.7471 13.3499 15.9527 18.7339 21.4837

1062 2.6528 5.3605 7.9216 10.6915 13.2642 15.9740 18.6627 21.3830

1066 2.6395 5.2864 7.9509 10.6040 13.1665 15.7914 18.6143 21.4684

1070 2.6226 5.3298 7.8502 10.5110 13.0406 15.7458 18.5645 21.3626

68
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 13. GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 9–16 lamps, measured

with the PR714 (small aperture spectroradiometer on 22 June 1993 (date and time are given in PDT). The radiance

was measured three times at 12 lamps and twice at 16 lamps.

λ 9 10 11 12 12 12 13 14 15 16 16

[nm] PR714 PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1041 1032 1031 1031 1028 1048 1017 1016 1015 1014 1030

382 0.9563 1.0800 1.2194 1.2816 1.3360 1.4714 1.5455 1.6927 1.7480

386 1.0893 1.2529 1.3861 1.5134 1.5012 1.5820 1.7344 1.8738 2.0303

390 1.2164 1.3403 1.5140 1.6462 1.6389 1.7877 1.9157 2.0707 2.2435

394 1.3396 1.5081 1.6756 1.8020 1.7988 1.9986 2.0861 2.2838 2.4826

398 1.4606 1.6651 1.8223 1.9504 1.9880 2.1516 2.3002 2.5014 2.6780

402 1.5756 1.7850 1.9828 2.1454 2.1454 2.3124 2.5409 2.7387 2.9162

406 1.7191 1.9256 2.1532 2.3154 2.3312 2.5250 2.7410 2.9601 3.1634

410 1.8518 2.0910 2.3092 2.5040 2.4976 2.7199 2.9444 3.2027 3.4378

411 2.4671 3.3309

414 1.9962 2.2592 2.5062 2.7157 2.7050 2.9253 3.1904 3.4406 3.6673

418 2.1587 2.4352 2.6970 2.9292 2.9240 3.1699 3.4454 3.7199 3.9690

422 2.3209 2.6250 2.8970 3.1618 3.1597 3.4079 3.7358 4.0099 4.2943

426 2.4949 2.8068 3.1353 3.4046 3.3838 3.6780 3.9992 4.2819 4.6250

430 2.6786 3.0195 3.3427 3.6115 3.5990 3.9305 4.2673 4.5759 4.9252

434 2.8513 3.2005 3.5298 3.8339 3.8517 4.1946 4.5501 4.8836 5.2317

438 3.0397 3.4079 3.7668 4.0936 4.1030 4.4598 4.8487 5.2034 5.5861

441 4.1330 5.5749

442 3.2269 3.6364 4.0440 4.3819 4.3667 4.7329 5.1536 5.5419 5.9383

446 3.4223 3.8543 4.2753 4.6365 4.6294 5.0221 5.4420 5.8822 6.3213

450 3.6207 4.0852 4.5068 4.8874 4.8853 5.3130 5.7529 6.2123 6.6727

454 3.8416 4.2998 4.7549 5.1585 5.1564 5.6095 6.0955 6.5228 7.0139

458 4.0152 4.5125 4.9954 5.4320 5.4135 5.8861 6.3916 6.8756 7.3615

462 4.2149 4.7448 5.2585 5.7028 5.7007 6.1838 6.7229 7.2467 7.7634

466 4.4458 5.0093 5.5349 5.9948 6.0107 6.5134 7.0679 7.6264 8.1789

470 4.6728 5.2635 5.8294 6.3039 6.3019 6.8390 7.4475 8.0194 8.6011

474 4.9212 5.5191 6.1090 6.6161 6.6211 7.1646 7.8141 8.4090 9.0221

478 5.1527 5.7877 6.4010 6.9545 6.9256 7.5420 8.1862 8.8212 9.4417

482 5.3842 6.0453 6.6950 7.2647 7.2409 7.8750 8.5631 9.2044 9.8769

486 5.6245 6.3014 6.9865 7.5769 7.5728 8.2219 8.9462 9.6118 10.3134

487 7.5369 10.2018

490 5.8802 6.6081 7.2927 7.9169 7.9138 8.5903 9.3534 10.0521 10.7820

494 6.1240 6.8903 7.6090 8.2501 8.2541 8.9658 9.7610 10.4866 11.2321

498 6.3645 7.1458 7.9162 8.5533 8.5861 9.3217 10.1487 10.8942 11.6595

502 6.6195 7.4309 8.2262 8.9190 8.9311 9.6912 10.5237 11.3170 12.1103

506 6.8676 7.7230 8.5215 9.2531 9.2511 10.0395 10.9081 11.7402 12.5824

510 7.1345 7.9997 8.8599 9.6062 9.6123 10.4216 11.3468 12.1805 13.0549

514 7.4019 8.3153 9.1931 9.9755 9.9826 10.8279 11.7717 12.6343 13.5476

518 7.6571 8.6126 9.5087 10.3202 10.3202 11.1962 12.1628 13.0790 14.0254

522 7.9176 8.9066 9.8488 10.6692 10.6892 11.5974 12.5955 13.5636 14.5317

526 8.2138 9.2202 10.1829 11.0662 11.0563 12.0289 13.0512 14.0437 15.0362

530 8.4903 9.5140 10.5278 11.4177 11.4277 12.4075 13.4772 14.4970 15.5368

534 8.7556 9.8296 10.8711 11.7829 11.7728 12.7758 13.9106 14.9642 16.0078

538 9.0417 10.1500 11.2153 12.1755 12.1652 13.2173 14.3613 15.4338 16.5165

542 9.3068 10.4625 11.5466 12.5284 12.5387 13.6125 14.7785 15.8932 17.0285

546 9.6009 10.7449 11.8695 12.9021 12.9021 14.0062 15.2228 16.3678 17.5435

547 12.8564 17.2924

69
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 13. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 9–16 lamps,

measured with the PR714 (small aperture spectroradiometer on 22 June 1993 (date and time are given in PDT). The

radiance was measured three times at 12 lamps and twice at 16 lamps.

λ 9 10 11 12 12 12 13 14 15 16 16

[nm] PR714 PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1041 1032 1031 1031 1028 1048 1017 1016 1015 1014 1030

550 9.8652 11.0519 12.2296 13.2764 13.2865 14.4339 15.6820 16.8597 18.0474

554 10.1552 11.3924 12.5702 13.6491 13.6590 14.8368 16.1136 17.3410 18.5485

558 10.4154 11.7037 12.9226 14.0226 14.0226 15.2316 16.5497 17.8082 19.0668

562 10.7009 12.0360 13.2915 14.4074 14.4074 15.6529 16.9979 18.2832 19.5885

566 11.0140 12.3482 13.6422 14.8058 14.7957 16.0897 17.4640 18.7780 20.1021

570 11.2848 12.6447 13.9639 15.1614 15.1614 16.4705 17.8811 19.2308 20.6211

574 11.5641 12.9497 14.3150 15.5580 15.5580 16.8927 18.3599 19.7251 21.1312

578 11.8499 13.2902 14.6795 15.9565 15.9462 17.3253 18.8065 20.2469 21.6260

582 12.1292 13.5933 15.0065 16.3079 16.3079 17.7008 19.2563 20.7102 22.1336

586 12.4057 13.9036 15.3512 16.6682 16.7084 18.1259 19.6942 21.1720 22.6499

590 12.6913 14.2405 15.7202 17.0707 17.0807 18.5206 20.1492 21.6587 23.1880

594 12.9809 14.5492 16.0387 17.4492 17.4295 18.9090 20.5760 22.1148 23.6634

598 13.2491 14.8461 16.3740 17.8232 17.8133 19.3314 21.0467 22.5944 24.1815

602 13.5299 15.1678 16.7560 18.1755 18.1854 19.7538 21.4811 23.0693 24.6973

606 13.7708 15.4297 17.0586 18.5076 18.4976 20.1165 21.8654 23.5043 25.1532

610 14.0509 15.7519 17.3925 18.8922 18.8821 20.4925 22.2841 23.9751 25.6459

614 14.3259 16.0836 17.7194 19.2536 19.2536 20.9097 22.7080 24.4353 26.1117

618 14.5746 16.3199 18.0345 19.6063 19.5859 21.2597 23.1275 24.8319 26.6180

622 14.8480 16.6200 18.3512 19.9399 19.9501 21.6508 23.5450 25.2966 27.0787

626 15.1198 16.9350 18.6792 20.3017 20.3321 22.0459 23.9726 25.7777 27.5523

630 15.3781 17.2347 19.0208 20.6656 20.6958 22.4415 24.3991 26.2255 28.0519

634 15.6456 17.5275 19.3393 21.0310 21.0410 22.8228 24.8248 26.6566 28.5385

638 15.9550 17.8361 19.6874 21.4292 21.3994 23.2805 25.2114 27.1523 29.0235

642 16.1530 18.1025 19.9625 21.7329 21.7230 23.5631 25.5921 27.5516 29.5011

646 16.3885 18.3858 20.2933 22.0510 22.0610 23.9585 25.9958 27.9533 29.9207

650 16.6856 18.6639 20.6123 22.3908 22.4107 24.2691 26.3573 28.3756 30.3039

654 16.9054 18.9144 20.8932 22.7013 22.6912 24.6299 26.7995 28.7784 30.7773

658 17.1519 19.1912 21.1799 22.9870 23.0274 24.9758 27.1765 29.1956 31.2248

661 22.8781 30.7001

662 17.3980 19.4955 21.5221 23.3662 23.3358 25.3827 27.5511 29.6384 31.6751

666 17.6516 19.7946 21.8157 23.6845 23.6845 25.7157 27.9704 30.0627 32.1142

670 17.8719 19.9929 22.0531 24.0017 24.0321 26.0314 28.3149 30.4461 32.5266

674 18.1243 20.2667 22.3386 24.2898 24.3301 26.4221 28.6851 30.8476 32.9497

678 18.3595 20.5882 22.6970 24.6559 24.6659 26.7847 29.0933 31.2621 33.4509

682 18.5597 20.7861 22.9326 24.9094 24.9094 27.0758 29.3921 31.6184 33.8448

686 18.7998 21.0367 23.2139 25.2222 25.2421 27.3994 29.7954 31.9925 34.2493

690 19.0265 21.2878 23.4893 25.5613 25.5414 27.7230 30.1337 32.3850 34.6363

694 19.2249 21.4991 23.7431 25.8269 25.8069 28.0009 30.4553 32.7194 34.9635

698 19.4024 21.7141 23.9754 26.1054 26.0751 28.3162 30.7894 33.0810 35.3422

702 19.6391 22.0100 24.2690 26.3958 26.3856 28.6344 31.1173 33.4679 35.7574

706 19.8509 22.2347 24.5157 26.6323 26.6528 28.9544 31.4512 33.7938 36.1365

710 20.0553 22.4391 24.7712 26.9166 26.9270 29.2383 31.8086 34.1407 36.5038

714 20.2621 22.6623 25.0107 27.2031 27.1823 29.5203 32.0556 34.4559 36.8666

718 20.4629 22.8868 25.2795 27.4746 27.4642 29.8153 32.4265 34.8088 37.2223

722 20.6664 23.1155 25.5126 27.7428 27.7324 30.1086 32.7244 35.1423 37.5602

726 20.8856 23.3397 25.7731 28.0304 28.0097 30.3913 33.0318 35.5066 37.9607

70
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 13. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 9–16 lamps,

measured with the PR714 (small aperture spectroradiometer on 22 June 1993 (date and time are given in PDT). The

radiance was measured three times at 12 lamps and twice at 16 lamps.

λ 9 10 11 12 12 12 13 14 15 16 16

[nm] PR714 PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1041 1032 1031 1031 1028 1048 1017 1016 1015 1014 1030

730 21.0695 23.5737 25.9854 28.2638 28.2945 30.6755 33.3541 35.8274 38.3008

734 21.2568 23.7900 26.2211 28.5297 28.5194 30.9608 33.6472 36.1600 38.6422

738 21.4490 23.9909 26.4618 28.7911 28.7708 31.2621 33.9356 36.4673 38.9586

742 21.6141 24.1722 26.6703 29.0186 28.9886 31.4768 34.1848 36.7429 39.2610

746 21.7460 24.3400 26.8446 29.2001 29.2001 31.6550 34.4180 37.0120 39.5265

750 21.8816 24.4939 27.0267 29.3609 29.3808 31.8937 34.6550 37.2574 39.7604

754 22.0489 24.6681 27.1977 29.5778 29.5579 32.1273 34.9058 37.5051 40.0446

758 22.1793 24.8216 27.3738 29.7659 29.7759 32.3481 35.1205 37.7328 40.3251

762 22.3508 25.0116 27.5620 30.0119 30.0019 32.5322 35.3737 38.0145 40.6452

766 22.4942 25.1931 27.7516 30.2197 30.2297 32.7882 35.6075 38.2863 40.8749

770 22.6622 25.3319 27.9614 30.4003 30.4003 33.0198 35.8701 38.5598 41.1492

772 29.3347 39.3107

774 22.8067 25.4928 28.1588 30.6034 30.5934 33.2090 36.1064 38.7724 41.4384

778 22.9737 25.6925 28.3406 30.8067 30.8067 33.4649 36.3455 39.0643 41.7023

782 23.1229 25.8468 28.4996 30.9999 30.9796 33.6425 36.5392 39.2631 41.9362

786 23.2462 25.9768 28.6563 31.1518 31.1518 33.8108 36.7766 39.4766 42.2072

790 23.4119 26.1385 28.8344 31.3355 31.3765 34.0108 36.9732 39.7100 42.4469

794 23.4944 26.2693 28.9723 31.5211 31.5417 34.2138 37.1532 39.9384 42.6208

798 23.5769 26.3683 29.0566 31.6007 31.6419 34.3302 37.2658 40.0571 42.7557

802 23.6645 26.4902 29.2030 31.7410 31.7513 34.4640 37.4542 40.2286 42.9413

806 23.7617 26.5943 29.3149 31.8724 31.8826 34.5624 37.5479 40.3806 43.1215

810 23.8334 26.6487 29.3928 31.9744 31.9540 34.6779 37.6761 40.5015 43.2660

814 23.9396 26.7584 29.5062 32.0918 32.1020 34.8194 37.8917 40.6497 43.4482

818 24.0755 26.8729 29.6602 32.2455 32.2455 35.0226 38.0422 40.8194 43.6268

822 24.1389 26.9746 29.7598 32.3735 32.3534 35.1386 38.1862 41.0018 43.7870

826 24.1951 27.0671 29.8383 32.4785 32.4785 35.2497 38.3131 41.1650 43.9462

830 24.3343 27.2125 30.0103 32.6168 32.6671 35.4246 38.4940 41.3220 44.1298

834 24.4195 27.3102 30.0695 32.7076 32.7581 35.5073 38.5900 41.4302 44.3209

838 24.4805 27.3654 30.1588 32.8100 32.8405 35.6441 38.7321 41.6068 44.4205

842 24.5404 27.4143 30.1965 32.8870 32.8768 35.7100 38.7877 41.6718 44.4948

846 24.6014 27.4806 30.3188 32.9418 32.9623 35.7903 38.8950 41.7947 44.6329

850 24.6569 27.5608 30.3716 33.0378 33.0378 35.8797 38.9695 41.8527 44.6739

854 24.7175 27.6260 30.4311 33.1429 33.1222 35.9790 39.0428 41.9721 44.7564

858 24.7974 27.7099 30.5079 33.2123 33.1915 36.0207 39.1516 42.0537 44.8725

862 24.7941 27.7438 30.5256 33.2233 33.2338 36.0680 39.1962 42.0934 44.9486

866 24.8606 27.7756 30.6171 33.2803 33.3223 36.1638 39.2989 42.1614 45.0868

870 24.9548 27.8759 30.7344 33.4365 33.4365 36.2846 39.4248 42.3772 45.2045

874 25.0252 27.9356 30.7938 33.4955 33.4955 36.3433 39.4937 42.4458 45.3040

878 25.0871 27.9894 30.8812 33.5852 33.5956 36.4770 39.5881 42.5635 45.4031

882 25.1454 28.0720 30.9155 33.6552 33.6656 36.5091 39.7158 42.6424 45.5274

886 25.1594 28.1005 30.9797 33.6732 33.6732 36.5627 39.7412 42.7236 45.5408

890 25.1495 28.0937 30.9453 33.6733 33.7042 36.5661 39.7265 42.7016 45.5635

894 25.1436 28.0897 30.9743 33.6544 33.6953 36.5698 39.7306 42.6562 45.5613

898 25.1341 28.1078 30.9695 33.7090 33.7090 36.5606 39.7685 42.7117 45.5530

902 25.0805 27.9983 30.8957 33.5898 33.5796 36.4567 39.6388 42.5769 45.4845

906 25.0470 27.9788 30.8092 33.5381 33.5482 36.4191 39.6045 42.5465 45.4478

71
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 13. (cont.) GSFC sphere spectral radiance [μWcm−2 nm−1sr−1], with intensity varied from 9–16 lamps,

measured with the PR714 (small aperture spectroradiometer on 22 June 1993 (date and time are given in PDT). The

radiance was measured three times at 12 lamps and twice at 16 lamps.

λ 9 10 11 12 12 12 13 14 15 16 16

[nm] PR714 PR714 PR714 PR714 PR714 SXR PR714 PR714 PR714 PR714 SXR

1041 1032 1031 1031 1028 1048 1017 1016 1015 1014 1030

910 25.0080 27.9239 30.7791 33.4824 33.5128 36.3679 39.5268 42.4630 45.3283

914 24.9917 27.8765 30.7209 33.4033 33.4437 36.3185 39.5576 42.4120 45.2361

918 24.9554 27.8531 30.7104 33.4562 33.4258 36.2527 39.4544 42.4130 45.1790

922 24.9378 27.8573 30.6856 33.3720 33.4328 36.2713 39.4138 42.3840 45.1617

926 24.9263 27.8690 30.7200 33.4183 33.3979 36.2897 39.4361 42.3584 45.1687

930 24.9132 27.8099 30.6860 33.3677 33.3370 36.2337 39.3964 42.3238 45.1897

934 24.9424 27.8374 30.6705 33.3801 33.3595 36.2545 39.4174 42.3433 45.1765

938 24.9091 27.7963 30.6422 33.3328 33.3225 36.2201 39.3557 42.3879 45.2130

942 24.8893 27.6755 30.5860 33.2997 33.2997 36.1998 39.2864 42.2072 45.1177

946 24.9086 27.7431 30.6088 33.3187 33.3187 36.2052 39.3512 42.2584 45.0722

950 24.8886 27.7744 30.6602 33.3376 33.3584 36.1713 39.3905 42.2762 45.0370

954 24.8542 27.7537 30.5697 33.2919 33.3023 36.2018 39.2995 42.2094 45.0463

958 24.8325 27.7699 30.6031 33.3009 33.3530 36.1862 39.3111 42.2173 45.0088

962 24.8352 27.8225 30.5704 33.2350 33.3599 36.1702 39.2824 42.2177 44.9760

966 24.7980 27.7013 30.5214 33.2166 33.1958 36.0887 39.1898 42.1035 44.9548

970 24.8326 27.6578 30.5560 33.2665 33.1205 36.1438 39.1463 42.1695 44.9322

974 24.7842 27.6939 30.4893 33.2327 33.1080 36.0176 39.1767 42.0656 44.8817

978 24.8262 27.6715 30.5376 33.2162 33.2370 36.0198 39.2924 42.1690 44.9101

982 24.8203 27.7156 30.5271 33.2336 33.2965 36.0135 39.2761 42.1190 44.9933

986 24.8381 27.6992 30.5079 33.3061 33.2746 36.0728 39.2483 42.1723 44.8343

990 24.8066 27.6733 30.5296 33.2394 33.1347 36.0433 39.1821 42.1116 44.8004

994 24.7533 27.5772 30.4850 33.1724 33.0989 35.9333 39.0931 42.0324 44.7933

998 24.7774 27.6016 30.4573 33.1555 33.1240 35.8852 39.0349 42.0796 44.7673

1002 24.7123 27.5709 30.4087 33.1102 33.0265 35.8852 39.0161 41.9480 44.5973

1006 24.7019 27.5772 30.4104 33.0863 32.9919 35.8986 39.0257 41.9009 44.6922

1010 24.6688 27.5188 30.3479 33.0309 33.1040 35.7974 38.9710 41.9254 44.7546

1014 24.6375 27.5336 30.3263 33.0258 33.0362 35.7254 38.9111 41.8279 44.6102

1018 24.6165 27.4616 30.2449 32.9456 32.9663 35.8217 38.8111 41.8006 44.5117

1022 24.5990 27.4413 30.2836 32.8882 32.8469 35.7615 38.8416 41.7046 44.4228

1026 24.4665 27.3165 30.2488 32.9650 32.9238 35.7018 38.7370 41.5972 44.5295

1030 24.5548 27.3757 30.2482 32.8632 32.8220 35.6533 38.6802 41.6247 44.7134

1034 24.5381 27.3289 30.0990 32.6831 32.8071 35.4738 38.6264 41.5515 44.2286

1038 24.5318 27.2219 29.9741 32.6125 32.5711 35.4371 38.6446 41.2312 44.2007

1042 24.3962 26.9071 29.9140 32.2700 32.5490 35.4732 38.2528 41.1047 44.2046

1046 24.2685 26.9821 29.5416 32.1730 32.5327 35.3594 38.1861 41.0745 43.9115

1050 24.0633 26.8172 29.5402 32.4178 32.3456 35.2440 37.8638 40.9890 43.3201

1054 23.9948 26.8558 29.6855 32.4107 32.3376 34.9585 38.0492 41.0668 43.4371

1058 23.8451 26.8257 29.6489 31.8529 32.1468 34.4767 38.1291 40.6479 43.5761

1062 23.9557 26.9502 29.5967 31.9480 32.1694 34.5945 37.5257 40.6151 43.4092

1066 23.9163 26.6975 29.6245 32.2703 31.8953 34.3640 37.5202 40.3327 43.3014

1070 23.6445 26.4116 28.8793 31.6671 31.7497 34.4549 37.3975 40.0407 43.0040

72
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 22. Spectral radiance of the BSI sphere measured with the 746/ISIC (solid line) on 17 June 1993, the

PR714 (dashed line) on 24 June 1993, the BSIXR on 17 June 1993 (o) and 23 June 1993 (+), and the SXR on 23

June 1993 (×). The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom

panel illustrates the departures of the PR714 radiances relative to the F269 calibrated scale. (Note that below

400 nm, the PR714 reads approximately 35% above [−0.35 relative difference] the 746/ISIC and is not graphed

in the bottom panel.)

73
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 23. Spectral radiance of the CHORS sphere (four 250 Wlamps: apertures 1.25, 1.25, 1.25, and 1.25)

measured with the 746/ISIC (19 June), the PR714 (18, 19, and 23 June 1993), the BSIXR (18 and 19 June

1993) [see key above; times in PDT], and the SXR (18 and 19 June 1993). The top panel illustrates spectral

radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom panel illustrates the departures of the PR714

radiances relative to the F269 calibrated scale of 19 June.

74
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 24. Spectral radiance of the CHORS sphere (four 250 Wlamps: apertures 1.25, 1.25, 1.25, and 1.25)

measured with the 746/ISIC (19 June), and the BSIXR (18 and 19 June 1993) [see key above; times in PDT].

The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom panel illustrates

the departures of the PR714 radiances relative to the F269 calibrated scale of 19 June.

75
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 25. Spectral radiance of the CHORS sphere (four 250 Wlamps: apertures 1.25, 1.25, 1.25, and 1.25)

measured with the 746/ISIC (19 June), the PR714 (18 June), and the BSIXR (18 June) [see key above; times

in PDT]; and the SXR on 18 June (a). The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the

sphere, and the bottom panel illustrates the departures of the PR714 and BSIXR radiances relative to the F269

calibrated scale of 19 June.

76
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. 26. Spectral radiance of the CHORS sphere (four 250 Wlamps: apertures 1.25, 1.25, 1.25, and 1.25)

measured with the 746/ISIC, the PR714, the SXR, and the BSIXR (all on 19 June) [see key above; times in

PDT]. The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom panel

illustrates the departures of the PR714 and BSIXR radiances relative to the F269 calibrated scale of 19 June.

77
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 27. Spectral radiance of the CHORS sphere (four 250 Wlamps: apertures 1.25, 1.25, 1.25, and 1.25)

measured with the 746/ISIC (19 June), and the PR714 (23 June) [see key above; times in PDT]. The top panel

illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom panel illustrates the departures

of the PR714 radiances relative to the F269 calibrated scale of 19 June.

78
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 14. BSI sphere (open aperture) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISIC, the PR714

(large aperture), and the BSIXR on 17, 23, and 24 June 1993; and the SXR on 23 June 1993 (date and time given in

PDT).

λ 746 BSIXR BSIXR SXR PR714 λ 746 BSIXR BSIXR SXR PR714

[nm] 17 June 17 June 23 June 23 June 24 June [nm] 17 June 17 June 23 June 23 June 24 June

1702 1715 1214 1230 1812 1702 1715 1214 1230 1812

350 0.0115 510 0.3639 0.3611

360 0.0216 514 0.3752

370 0.0248 518 0.3873

380 0.0321 520 0.3980

382 0.0396 522 0.4019

386 0.0466 526 0.4166

390 0.0416 0.0513 530 0.4326 0.4297

394 0.0591 534 0.4432

398 0.0647 538 0.4576

400 0.0536 540 0.4664

402 0.0706 542 0.4699

406 0.0780 546 0.4836

410 0.0874 0.0859 547 0.5195

411 0.0915 550 0.4994 0.4983

412 0.0937 0.0922 554 0.5110

414 0.0937 558 0.5250

418 0.1019 560 0.5336

420 0.1076 562 0.5386

422 0.1102 566 0.5522

426 0.1203 570 0.5660 0.5653

430 0.1304 0.1296 574 0.5796

434 0.1382 578 0.5915

438 0.1483 580 0.5977

440 0.1541 582 0.6012

441 0.1622 586 0.6141

442 0.1593 589 0.6289 0.6242

443 0.1643 0.1626 590 0.6284 0.6278

446 0.1691 594 0.6408

450 0.1797 0.1791 598 0.6556

454 0.1904 600 0.6605

458 0.2003 602 0.6684

460 0.2062 606 0.6777

462 0.2105 610 0.6913 0.6889

466 0.2216 614 0.6989

470 0.2368 0.2333 618 0.7074

474 0.2463 620 0.7198

478 0.2598 622 0.7195

480 0.2659 626 0.7334

482 0.2716 630 0.7471 0.7461

486 0.2827 634 0.7577

487 0.3041 638 0.7675

490 0.2971 0.3026 0.3001 0.2952 640 0.7730

494 0.3092 642 0.7768

498 0.3235 646 0.7861

500 0.3299 650 0.7978 0.7923

502 0.3364 654 0.8015

506 0.3482 656 0.8171 0.8046

79
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 14. (cont.) BSI sphere (open aperture) spectral radiance [μWcm−2 nm−1sr−1] measured with the 746/ISIC,

the PR714 (large aperture), and the BSIXR on 17, 23, and 24 June 1993; and the SXR on 23 June 1993 (date and

time given in PDT).

λ 746 BSIXR BSIXR SXR PR714 λ 746 BSIXR BSIXR SXR PR714

[nm] 17 June 17 June 23 June 23 June 24 June [nm] 17 June 17 June 23 June 23 June 24 June

1702 1715 1214 1230 1812 1702 1715 1214 1230 1812

658 0.8095 802 1.1325

660 0.8210 806 1.1353

661 0.8761 810 1.1498 1.1344

662 0.8214 814 1.1334

666 0.8322 818 1.1373

670 0.8434 0.8410 820 1.1486

674 0.8535 822 1.1363

678 0.8629 826 1.1330

680 0.8656 830 1.1479 1.1363

682 0.8678 834 1.1356

683 0.8753 0.8706 838 1.1331

686 0.8748 840 1.1470

690 0.8894 0.8833 842 1.1332

694 0.8890 846 1.1327

698 0.8993 850 1.1460 1.1332

700 0.9176 854 1.1310

702 0.9131 858 1.1303

706 0.9275 860 1.1468

710 0.9480 0.9459 862 1.1282

714 0.9632 866 1.1256

718 0.9783 870 1.1443 1.1297

720 0.9810 874 1.1333

722 0.9931 878 1.1347

726 1.0070 880 1.1442

730 1.0166 1.0151 882 1.1343

734 1.0280 886 1.1341

738 1.0374 890 1.1404 1.1337

740 1.0505 894 1.1376

742 1.0392 898 1.1389

746 1.0430 900 1.1350

750 1.0775 1.0563 902 1.1298

754 1.0766 906 1.1146

758 1.0936 910 1.1299 1.0946

760 1.0988 914 1.0852

762 1.0976 918 1.0857

766 1.1052 920 1.1236

770 1.1205 1.1159 922 1.0908

772 1.1638 926 1.0931

774 1.1247 930 1.1114 1.0971

778 1.1270 934 1.0930

780 1.1351 938 1.0910

782 1.1266 940 1.1002

786 1.1288 942 1.0906

790 1.1432 1.1314 946 1.0888

794 1.1304 950 1.0993 1.0870

798 1.1299 954 1.0816

800 1.1485 958 1.0833

80
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 14. (cont.) BSI sphere (open aperture) spectral radiance [μWcm−2 nm−1sr−1] measured with the

746/ISIC, the PR714 (large aperture), and the BSIXR on 17, 23, and 24 June 1993; and the SXR on 23 June

1993 (date and time given in PDT).

λ 746 BSIXR BSIXR SXR PR714 λ 746 BSIXR BSIXR SXR PR714

[nm] 17 June 17 June 23 June 23 June 24 June [nm] 17 June 17 June 23 June 23 June 24 June

1702 1715 1214 1230 1812 1702 1715 1214 1230 1812

960 1.0972 1014 1.0806

962 1.0820 1018 1.0781

966 1.0769 1022 1.0770

970 1.0936 1.0729 1026 1.0816

974 1.0729 1030 1.0728

978 1.0765 1034 1.0657

980 1.0924 1038 1.0715

982 1.0786 1042 1.0620

986 1.0783 1046 1.0576

990 1.0919 1.0791 1050 1.0586

994 1.0805 1054 1.0652

998 1.0808 1058 1.0767

1000 1.0904 1062 1.0608

1002 1.0832 1066 1.0715

1006 1.0838 1070 1.0521

1010 1.0809

(1,000 nm). Below 420 nm, where PR714 radiances are up

to 20% lower, the 746/ISIC log indicates the data were

“very noisy below 450 nm.” SXR measurements do little

to clarify these large discrepancies in radiance estimates

for this sphere; they exceed PR714 radiances by 3–5%,

and are approximately 1–2% less than 746/ISIC radiances

(excluding 410.5 nm where the 746/ISIC data are clearly

unreliable).

3.2.5 The WFF Sphere

The WFF sphere has two lamps which are operated

simultaneously. When stating that the aperture is open

or that a specific aperture number was used, this refers

to both lamps. Spectral radiance of the WFF sphere was

measured with the 746/ISIC (F269) on 18 June 1993 (open,

No. 3, and No. 5 apertures); the PR714 on 21 June (open,

No. 3 , No. 5 , and No. 6 apertures) and 23 June (open);

the BSIXR on 18 June (open); and the SXR on 21 June

(open, No. 3 , No. 5 , and No. 6 apertures) and 23 June

(open). The calibrated radiances from these measurements

are listed in Table 18 and illustrated in Fig. 29. With open

apertures, the PR714 radiances are approximately 2.5%

higher on 21 June, and 3–5% higher on 23 June, than the

746/ISIC (F269) radiances on 18 June; the comparisons of

No. 3 and No. 5 apertures also show the PR714 on 21 June

to be higher, by approximately 2.5% and 1%, respectively.

The BSIXR radiances (18 June) are also larger than those

measured for this sphere on 18 June with the 746/ISIC

(F269). SXR measurements of the WFF sphere on 21 and

23 June exceed 746/ISIC (18 June) by 3–6.5%, and exceed

concurrent PR714 radiances by 0.5% up to almost 4%.

3.2.6 The NOAA Sphere

The spectral radiance of the NOAA Optronics 420M

sphere radiance source was measured with the PR714 and

the SXR, with 420M settings D40,S3,W6 (corresponding

to particular settings of lamp location and aperture sizes)

on 22 and 24 June 1993 and D100,S3,W5 on 22 June (Table 19 and Fig. 30). The three D40,S3,W6 radiance measurements from 22 and 24 June 1993 all agree to within

less than 1%. SXR radiances for this sphere exceed PR714

radiances by 4–5.5% on 22 June 1993, and radiance differences on 24 June 1993 range from −5 to +3%.

3.3 Discussion

The initial indications of less than 1% apparent relative stability in the radiance scale of the GSFC sphere, as

measured with the 746/ISIC (F269) on 15–19 June 1993,

are very encouraging (Fig. 17). Measurements on subsequent days with the PR714, however, indicate apparent

drifts in the radiance scale by as much as 3% (Figs. 19–

21). Similar comparisons, based primarily on the PR714,

also showed relatively large apparent day-to-day variabilities in the scales of some of the other spheres: BSI up to

5% (Fig. 22), CHORS up to 7% (Figs. 23–27) and WFF

up to 5% (Fig. 29). However, the PR714 measurements of

the Optronics 420M sphere on two days agreed with less

than 1% (Fig. 30). From these data alone, it cannot be

resolved whether apparent changes are actual measures of

variability in sphere radiance, whether the PR714 itself is

subject to wavelength dependent responsivity variations of

81
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 15. The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1sr−1]

measured with the PR714, BSIXR, and SXR on 18 June 1993 (date and time are given in PDT). The 1805 and 1810

PR714 readings viewed the exit port 10◦ off axis, and the 1815 and 1820 radiances were measured on axis.

λ BSIXR BSIXR BSIXR SXR PR714 PR714† PR714 PR714†

[nm] 1248 1411 1615 1804 1805 1810 1815 1820

382 0.3334 0.3326 0.3239 0.3214

386 0.3777 0.3732 0.3738 0.3739

390 0.4301 0.4232 0.4223 0.4221

394 0.4793 0.4850 0.4877 0.4819

398 0.5329 0.5357 0.5358 0.5372

402 0.5877 0.5871 0.5857 0.5826

406 0.6412 0.6409 0.6353 0.6345

410 0.6923 0.6925 0.6904 0.6920

411 0.7167

412 0.7379 0.7385 0.7439

414 0.7465 0.7442 0.7486 0.7494

418 0.8023 0.8018 0.8037 0.8026

422 0.8629 0.8620 0.8612 0.8620

426 0.9313 0.9315 0.9277 0.9289

430 0.9914 0.9909 0.9895 0.9892

434 1.0549 1.0558 1.0528 1.0548

438 1.1191 1.1215 1.1212 1.1196

441 1.1772

442 1.1923 1.1944 1.1943 1.1934

443 1.2139 1.2130 1.2231

446 1.2629 1.2637 1.2629 1.2646

450 1.3382 1.3375 1.3352 1.3355

454 1.4147 1.4163 1.4158 1.4134

458 1.4877 1.4889 1.4857 1.4850

462 1.5572 1.5568 1.5582 1.5568

466 1.6326 1.6337 1.6356 1.6346

470 1.7254 1.7218 1.7244 1.7247

474 1.8232 1.8186 1.8202 1.8205

478 1.9089 1.9104 1.9079 1.9084

482 1.9864 1.9875 1.9874 1.9865

486 2.0606 2.0626 2.0606 2.0587

487 2.1347

490 2.1911 2.1851 2.1985 2.1544 2.1543 2.1554 2.1543

494 2.2583 2.2575 2.2593 2.2584

498 2.3588 2.3572 2.3568 2.3562

502 2.4432 2.4458 2.4411 2.4409

506 2.5165 2.5182 2.5165 2.5192

510 2.6049 2.6072 2.6069 2.6043

514 2.7065 2.7058 2.7075 2.7048

518 2.8011 2.8001 2.7980 2.8001

522 2.8964 2.8949 2.8924 2.8911

526 2.9824 2.9890 2.9854 2.9813

530 3.0634 3.0645 3.0644 3.0636

534 3.1458 3.1494 3.1479 3.1455

538 3.2441 3.2458 3.2461 3.2448

542 3.3351 3.3348 3.3310 3.3338

† Denotes corrected radiances measured with the large PR714 aperture.

82
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 15. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the PR714, BSIXR, and SXR on 18 June 1993 (date and time are given in PDT). The 1805 and

1810 PR714 readings viewed the exit port 10◦ off axis, and the 1815 and 1820 radiances were measured on axis.

λ BSIXR BSIXR BSIXR SXR PR714 PR714† PR714 PR714†

[nm] 1248 1411 1615 1804 1805 1810 1815 1820

546 3.4187 3.4186 3.4187 3.4205

547 3.4846

550 3.4978 3.4973 3.5008 3.4973

554 3.5761 3.5763 3.5741 3.5753

558 3.6657 3.6669 3.6627 3.6622

562 3.7463 3.7501 3.7483 3.7472

566 3.8349 3.8358 3.8328 3.8319

570 3.9182 3.9219 3.9182 3.9170

574 3.9888 3.9931 3.9909 3.9921

578 4.0576 4.0558 4.0576 4.0558

582 4.1237 4.1236 4.1248 4.1227

586 4.2073 4.2032 4.2042 4.2051

589 4.2389 4.2353 4.2454

590 4.2920 4.2895 4.2890 4.2934

594 4.3756 4.3729 4.3746 4.3748

598 4.4459 4.4480 4.4469 4.4403

602 4.5007 4.5041 4.4997 4.4992

606 4.5460 4.5483 4.5450 4.5415

610 4.5998 4.6025 4.5977 4.5996

614 4.6696 4.6713 4.6696 4.6683

618 4.7418 4.7422 4.7418 4.7402

622 4.8251 4.8214 4.8261 4.8195

626 4.9051 4.8987 4.9010 4.9026

630 4.9666 4.9641 4.9616 4.9592

634 4.9990 4.9992 4.9970 4.9943

638 5.0164 5.0172 5.0164 5.0133

642 5.0468 5.0472 5.0399 5.0385

646 5.0783 5.0781 5.0763 5.0722

650 5.1226 5.1282 5.1306 5.1205

654 5.2102 5.2183 5.2173 5.2095

656 5.2132 5.2110 5.2183

658 5.3101 5.3101 5.3111 5.3072

661 5.5261

662 5.4038 5.3997 5.4008 5.3978

666 5.4590 5.4595 5.4641 5.4595

670 5.4915 5.4918 5.4894 5.4889

674 5.4936 5.4939 5.4916 5.4890

678 5.4909 5.4934 5.4899 5.4895

682 5.4821 5.4813 5.4771 5.4804

683 5.4888 5.4762 5.4807

686 5.4819 5.4840 5.4809 5.4869

690 5.5297 5.5320 5.5286 5.5282

694 5.6032 5.6049 5.5972 5.5991

698 5.6875 5.6915 5.6915 5.6896

702 5.7828 5.7833 5.7849 5.7793

706 5.8669 5.8679 5.8700 5.8659

† Denotes corrected radiances measured with the large PR714 aperture.

83
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 15. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the PR714, BSIXR, and SXR on 18 June 1993 (date and time are given in PDT). The 1805 and

1810 PR714 readings viewed the exit port 10◦ off axis, and the 1815 and 1820 radiances were measured on axis.

λ BSIXR BSIXR BSIXR SXR PR714 PR714† PR714 PR714†

[nm] 1248 1411 1615 1804 1805 1810 1815 1820

710 5.9295 5.9226 5.9306 5.9276

714 5.9425 5.9386 5.9373 5.9406

718 5.8975 5.8935 5.8954 5.8976

722 5.8477 5.8516 5.8498 5.8486

726 5.8132 5.8193 5.8173 5.8143

730 5.7698 5.7703 5.7708 5.7703

734 5.7550 5.7572 5.7570 5.7543

738 5.7633 5.7592 5.7572 5.7621

742 5.7757 5.7757 5.7747 5.7776

746 5.8529 5.8559 5.8529 5.8531

750 5.9934 5.9897 5.9963 5.9935

754 6.1068 6.1064 6.1078 6.1045

758 6.1463 6.1420 6.1433 6.1450

762 6.0837 6.0843 6.0827 6.0824

766 6.0680 6.0623 6.0630 6.0594

770 6.0640 6.0646 6.0630 6.0616

772 6.1470

774 6.0291 6.0293 6.0251 6.0234

778 5.9693 5.9730 5.9754 5.9700

782 5.9255 5.9232 5.9215 5.9212

786 5.9113 5.9051 5.9061 5.9081

790 5.9135 5.9111 5.9094 5.9160

794 5.9209 5.9202 5.9240 5.9222

798 5.9493 5.9475 5.9504 5.9535

802 5.9999 5.9975 6.0019 5.9955

806 6.0372 6.0357 6.0393 6.0347

810 6.0625 6.0570 6.0615 6.0570

814 6.0686 6.0597 6.0645 6.0655

818 6.0714 6.0697 6.0653 6.0726

822 6.0478 6.0481 6.0489 6.0471

826 6.0130 6.0082 6.0160 6.0073

830 5.9739 5.9679 5.9779 5.9709

834 5.9290 5.9240 5.9290 5.9260

838 5.8855 5.8764 5.8753 5.8774

842 5.8436 5.8382 5.8436 5.8422

846 5.8148 5.8148 5.8179 5.8128

850 5.8056 5.8061 5.8098 5.8041

854 5.8057 5.8045 5.8109 5.8065

858 5.8457 5.8380 5.8384 5.8380

862 5.8920 5.8841 5.8836 5.8912

866 5.9158 5.9080 5.9127 5.9161

870 5.9403 5.9308 5.9382 5.9389

874 5.9585 5.9560 5.9616 5.9570

878 5.9539 5.9495 5.9570 5.9536

882 5.9413 5.9368 5.9330 5.9358

886 5.9204 5.9107 5.9080 5.9127

† Denotes corrected radiances measured with the large PR714 aperture.

84
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 15. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the PR714, BSIXR, and SXR on 18 June 1993 (date and time are given in PDT). The 1805 and

1810 PR714 readings viewed the exit port 10◦ off axis, and the 1815 and 1820 radiances were measured on axis.

λ BSIXR BSIXR BSIXR SXR PR714 PR714† PR714 PR714†

[nm] 1248 1411 1615 1804 1805 1810 1815 1820

890 5.8586 5.8508 5.8524 5.8588

894 5.7335 5.7301 5.7407 5.7411

898 5.5584 5.5524 5.5615 5.5544

902 5.3363 5.3324 5.3292 5.3264

906 5.1474 5.1440 5.1413 5.1469

910 5.0978 5.1025 5.0917 5.0938

914 5.2635 5.2575 5.2646 5.2633

918 5.4774 5.4731 5.4703 5.4711

922 5.6566 5.6541 5.6556 5.6658

926 5.7958 5.7851 5.7948 5.8058

930 5.8322 5.8364 5.8486 5.8403

934 5.8302 5.8281 5.8271 5.8301

938 5.8459 5.8487 5.8470 5.8527

942 5.8883 5.8739 5.8852 5.8820

946 5.8965 5.8954 5.9058 5.8864

950 5.9226 5.9181 5.9299 5.9291

954 5.9450 5.9396 5.9523 5.9547

958 5.9988 5.9776 6.0102 6.0048

962 6.0360 6.0224 6.0370 6.0355

966 6.0543 6.0354 6.0470 6.0464

970 6.0726 6.0578 6.0664 6.0679

974 6.0885 6.0740 6.0729 6.0790

978 6.1013 6.1113 6.1211 6.1093

982 6.1285 6.1181 6.1253 6.1222

986 6.1068 6.1000 6.1100 6.0919

990 6.0881 6.0832 6.0808 6.0873

994 6.0739 6.0655 6.0687 6.0625

998 6.0295 6.0162 6.0085 6.0335

1002 5.9707 5.9670 6.0042 5.9711

1006 5.9446 5.9381 5.9436 5.9340

1010 5.8827 5.8687 5.8597 5.8677

1014 5.8036 5.8012 5.7777 5.7982

1018 5.7480 5.7458 5.7469 5.7298

1022 5.7312 5.7298 5.7280 5.7189

1026 5.7267 5.7414 5.7318 5.7354

1030 5.7408 5.7571 5.7377 5.7353

1034 5.7841 5.7751 5.7779 5.7771

1038 5.8396 5.8349 5.8272 5.8148

1042 5.8268 5.8400 5.7948 5.8330

1046 5.8045 5.8174 5.7922 5.7818

1050 5.7832 5.8282 5.8204 5.8193

1054 5.8087 5.8653 5.8358 5.8371

1058 5.8196 5.8540 5.8290 5.8437

1062 5.8318 5.7626 5.8044 5.7657

1066 5.8103 5.7511 5.7405 5.8373

1070 5.7531 5.7551 5.7449 5.7419

† Denotes corrected radiances measured with the large PR714 aperture.

85
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 16. The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1sr−1]

measured with the 746/ISIC, PR714, BSIXR, and SXR on 19 and 23 June 1993 (date and time given in PDT).

λ PR714 PR714† SXR PR714 PR714† BSIXR 746 SXR PR714 PR714‡ PR714‡ PR714‡

[nm] 1045 1046 1047 1048 1050 1100 1232 1357 1410 0950 1050§ 1611

350 0.0869

360 0.1638

370 0.2094

380 0.2641

382 0.3255 0.3273 0.3249 0.3263 0.3277 0.3323 0.3374 0.3482

386 0.3737 0.3798 0.3815 0.3798 0.3643 0.3860 0.3817 0.4006

390 0.4270 0.4244 0.4197 0.4290 0.3461 0.4214 0.4396 0.4429 0.4582

394 0.4793 0.4824 0.4854 0.4824 0.4898 0.5023 0.5094 0.5159

398 0.5307 0.5347 0.5412 0.5329 0.5395 0.5537 0.5593 0.5701

400 0.4413

402 0.5822 0.5881 0.5893 0.5871 0.5928 0.6053 0.6152 0.6296

406 0.6386 0.6418 0.6437 0.6418 0.6466 0.6648 0.6700 0.6816

410 0.6930 0.6918 0.6976 0.6968 0.7060 0.6942 0.7188 0.7192 0.7340

412 0.7365

411 0.7182 0.7228

414 0.7441 0.7460 0.7497 0.7494 0.7494 0.7723 0.7799 0.7945

418 0.8059 0.8051 0.8049 0.8073 0.8087 0.8340 0.8392 0.8573

420 0.8436

422 0.8629 0.8644 0.8666 0.8652 0.8668 0.8927 0.8995 0.9185

426 0.9292 0.9288 0.9339 0.9329 0.9298 0.9574 0.9639 0.9879

430 0.9938 0.9938 0.9942 0.9949 1.0024 0.9939 1.0275 1.0317 1.0564

434 1.0570 1.0558 1.0623 1.0608 1.0591 1.0937 1.1000 1.1231

438 1.1243 1.1235 1.1284 1.1283 1.1273 1.1594 1.1677 1.1915

440 1.1630

441 1.1796 1.1864

442 1.1974 1.1954 1.1994 1.2002 1.1984 1.2337 1.2397 1.2589

443 1.2133

446 1.2649 1.2656 1.2709 1.2676 1.2689 1.3094 1.3145 1.3367

450 1.3362 1.3395 1.3433 1.3405 1.3390 1.3403 1.3853 1.3904 1.4180

454 1.4168 1.4193 1.4240 1.4223 1.4219 1.4631 1.4714 1.4992

458 1.4929 1.4899 1.4949 1.4977 1.4918 1.5309 1.5411 1.5679

460 1.5376

462 1.5623 1.5617 1.5653 1.5674 1.5643 1.6030 1.6112 1.6407

466 1.6366 1.6366 1.6435 1.6432 1.6386 1.6903 1.6953 1.7242

470 1.7284 1.7314 1.7333 1.7333 1.7458 1.7284 1.7859 1.7889 1.8217

474 1.8242 1.8274 1.8293 1.8303 1.8283 1.8828 1.8858 1.9222

478 1.9151 1.9164 1.9213 1.9184 1.9151 1.9626 1.9729 2.0048

480 1.9578

482 1.9905 1.9924 1.9968 1.9944 1.9905 2.0372 2.0507 2.0829

486 2.0658 2.0674 2.0730 2.0713 2.0668 2.1163 2.1317 2.1667

487 2.1333 2.1438

490 2.1594 2.1601 2.1665 2.1668 2.1976 2.1814 2.1604 2.2269 2.2329 2.2671

494 2.2653 2.2670 2.2713 2.2718 2.2633 2.3339 2.3389 2.3737

498 2.3627 2.3659 2.3677 2.3668 2.3607 2.4263 2.4293 2.4651

500 2.4115

502 2.4492 2.4497 2.4552 2.4526 2.4472 2.5044 2.5114 2.5496

† Denotes corrected radiances measured with the large PR714 aperture; all others were measured with the small aperture.

‡ Radiances measured on 23 June 1993; all other measurements were taken on 19 June 1993.

§ On 23 June, the 1050 PDT PR714 radiances were measured 20◦off axis.

86
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 16. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the 746/ISIC, PR714, BSIXR, and SXR on 19 and 23 June 1993 (date and time given in PDT).

λ PR714 PR714† SXR PR714 PR714† BSIXR 746 SXR PR714 PR714‡ PR714‡ PR714‡

[nm] 1045 1046 1047 1048 1050 1100 1232 1357 1410 0950 1050§ 1611

506 2.5226 2.5211 2.5307 2.5280 2.5256 2.5824 2.5916 2.6301

510 2.6100 2.6111 2.6191 2.6180 2.6307 2.6110 2.6750 2.6872 2.7259

514 2.7065 2.7078 2.7136 2.7155 2.7105 2.7856 2.7937 2.8404

518 2.8021 2.8030 2.8131 2.8107 2.8021 2.8806 2.8856 2.9320

520 2.8737

522 2.9023 2.9064 2.9113 2.9103 2.9004 2.9712 2.9792 3.0221

526 2.9953 2.9948 3.0003 2.9987 2.9874 3.0608 3.0648 3.1085

530 3.0704 3.0714 3.0804 3.0791 3.0858 3.0694 3.1374 3.1474 3.1953

534 3.1509 3.1533 3.1641 3.1602 3.1509 3.2249 3.2370 3.2897

538 3.2461 3.2487 3.2584 3.2547 3.2461 3.3278 3.3401 3.3891

540 3.3109

542 3.3351 3.3357 3.3454 3.3426 3.3331 3.4149 3.4241 3.4814

546 3.4239 3.4215 3.4300 3.4302 3.4208 3.5026 3.5077 3.5660

547 3.4896 3.5078

550 3.5058 3.5088 3.5139 3.5146 3.5314 3.5028 3.5873 3.5924 3.6437

554 3.5860 3.5877 3.5949 3.5916 3.5791 3.6711 3.6741 3.7255

558 3.6716 3.6756 3.6816 3.6775 3.6667 3.7559 3.7628 3.8173

560 3.7387

562 3.7553 3.7569 3.7682 3.7637 3.7493 3.8479 3.8460 3.9018

566 3.8409 3.8407 3.8499 3.8494 3.8359 3.9261 3.9332 3.9853

570 3.9202 3.9200 3.9314 3.9288 3.9328 3.9152 4.0065 4.0126 4.0694

574 3.9960 3.9921 4.0031 4.0010 3.9868 4.0795 4.0897 4.1447

578 4.0627 4.0636 4.0678 4.0705 4.0576 4.1577 4.1648 4.2220

580 4.1285

582 4.1308 4.1324 4.1390 4.1392 4.1258 4.2285 4.2417 4.3017

586 4.2093 4.2147 4.2234 4.2204 4.2052 4.3209 4.3219 4.3872

589 4.2458

590 4.3039 4.3020 4.3148 4.3144 4.3384 4.2900 4.4132 4.4112 4.4717

594 4.3865 4.3901 4.3973 4.3968 4.3746 4.4900 4.4841 4.5492

598 4.4538 4.4585 4.4607 4.4605 4.4410 4.5465 4.5484 4.6066

600 4.4712

602 4.5106 4.5137 4.5225 4.5157 4.4947 4.6020 4.6039 4.6595

606 4.5519 4.5542 4.5620 4.5600 4.5370 4.6519 4.6479 4.7119

610 4.6048 4.6035 4.6158 4.6133 4.6186 4.5927 4.7225 4.7215 4.7860

614 4.6717 4.6762 4.6838 4.6781 4.6656 4.8098 4.8058 4.8769

618 4.7429 4.7471 4.7572 4.7539 4.7367 4.8847 4.8868 4.9643

620 4.8398

622 4.8312 4.8341 4.8353 4.8419 4.8220 4.9656 4.9677 5.0481

626 4.9111 4.9143 4.9182 4.9192 4.8990 5.0349 5.0338 5.1058

630 4.9747 4.9864 4.9888 4.9825 4.9781 4.9595 5.0796 5.0756 5.1432

634 5.0100 5.0234 5.0280 5.0176 4.9950 5.1031 5.0991 5.1662

638 5.0244 5.0336 5.0393 5.0317 5.0005 5.1209 5.1129 5.1816

640 5.0290

642 5.0438 5.0511 5.0548 5.0491 5.0219 5.1532 5.1532 5.2199

646 5.0763 5.0839 5.0873 5.0848 5.0514 5.2012 5.2032 5.2771

650 5.1286 5.1369 5.1366 5.1321 5.1764 5.1116 5.2775 5.2884 5.3574

† Denotes corrected radiances measured with the large PR714 aperture; all others were measured with the small aperture.

‡ Radiances measured on 23 June 1993; all other measurements were taken on 19 June 1993.

§ On 23 June, the 1050 PDT PR714 radiances were measured 20◦off axis.

87
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 16. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the 746/ISIC, PR714, BSIXR, and SXR on 19 and 23 June 1993 (date and time given in PDT).

λ PR714 PR714† SXR PR714 PR714† BSIXR 746 SXR PR714 PR714‡ PR714‡ PR714‡

[nm] 1045 1046 1047 1048 1050 1100 1232 1357 1410 0950 1050§ 1611

654 5.2193 5.2192 5.2263 5.2261 5.1982 5.3760 5.3800 5.4694

656 5.2044

658 5.3081 5.3208 5.3303 5.3208 5.3021 5.4686 5.4757 5.5625

660 5.4263

661 5.5395 5.5672

662 5.4069 5.4173 5.4180 5.4154 5.3937 5.5538 5.5507 5.6328

666 5.4783 5.4840 5.4844 5.4821 5.4580 5.5829 5.5951 5.6774

670 5.5077 5.5133 5.5199 5.5153 5.5252 5.4844 5.5919 5.5919 5.6741

674 5.5097 5.5153 5.5208 5.5182 5.4846 5.5902 5.5801 5.6576

678 5.5089 5.5079 5.5158 5.5137 5.4799 5.5868 5.5748 5.6548

680 5.4884

682 5.4871 5.4891 5.4980 5.4929 5.4641 5.5909 5.5869 5.6747

683 5.4807

686 5.4878 5.4917 5.5067 5.4946 5.4650 5.6340 5.6230 5.7066

690 5.5326 5.5427 5.5516 5.5398 5.5938 5.5097 5.7090 5.6980 5.7817

694 5.6082 5.6059 5.6152 5.6136 5.5882 5.7845 5.7885 5.8757

698 5.7006 5.6993 5.7016 5.7013 5.6784 5.8833 5.8904 5.9822

700 5.8476

702 5.7920 5.7981 5.7981 5.7971 5.7696 5.9803 5.9752 6.0647

706 5.8762 5.8849 5.8854 5.8799 5.8494 6.0436 6.0385 6.1248

710 5.9399 5.9508 5.9472 5.9467 5.9949 5.9119 6.0746 6.0653 6.1586

714 5.9550 5.9599 5.9643 5.9599 5.9186 6.0599 6.0495 6.1358

718 5.9110 5.9188 5.9246 5.9188 5.8788 5.9932 5.9943 6.0754

720 5.8917

722 5.8612 5.8678 5.8758 5.8667 5.8247 5.9404 5.9415 6.0196

726 5.8277 5.8344 5.8380 5.8283 5.7894 5.9219 5.9209 5.9996

730 5.7790 5.7871 5.7903 5.7822 5.8039 5.7492 5.9114 5.9062 5.9976

734 5.7590 5.7651 5.7662 5.7612 5.7253 5.9245 5.9194 6.0144

738 5.7592 5.7679 5.7714 5.7621 5.7299 5.9587 5.9527 6.0458

740 5.8543

742 5.7697 5.7795 5.7857 5.7738 5.7418 5.9916 5.9826 6.0815

746 5.8559 5.8616 5.8609 5.8521 5.8221 6.0746 6.0706 6.1740

750 5.9894 6.0059 6.0053 5.9954 6.2021 5.9616 6.2089 6.2069 6.3013

754 6.1088 6.1180 6.1187 6.1142 6.0729 6.3139 6.3060 6.3906

758 6.1533 6.1606 6.1603 6.1547 6.1103 6.3255 6.3185 6.4026

760 6.1891

762 6.0968 6.1058 6.1048 6.0950 6.0446 6.2404 6.2193 6.3066

766 6.0750 6.0905 6.0861 6.0798 6.0259 6.1985 6.1834 6.2617

770 6.0760 6.0851 6.0871 6.0793 6.1731 6.0228 6.1814 6.1644 6.2467

772 6.1738 6.1878

774 6.0412 6.0519 6.0493 6.0401 5.9869 6.1428 6.1277 6.2143

778 5.9885 5.9947 5.9946 5.9898 5.9339 6.1078 6.0916 6.1846

780 6.0297

782 5.9276 5.9460 5.9449 5.9291 5.8849 6.0770 6.0689 6.1573

786 5.9113 5.9210 5.9194 5.9141 5.8683 6.0759 6.0729 6.1710

790 5.9176 5.9160 5.9186 5.9150 6.0303 5.8694 6.1062 6.1000 6.2015

† Denotes corrected radiances measured with the large PR714 aperture; all others were measured with the small aperture.

‡ Radiances measured on 23 June 1993; all other measurements were taken on 19 June 1993.

§ On 23 June, the 1050 PDT PR714 radiances were measured 20◦off axis.

88
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 16. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the 746/ISIC, PR714, BSIXR, and SXR on 19 and 23 June 1993 (date and time given in PDT).

λ PR714 PR714† SXR PR714 PR714† BSIXR 746 SXR PR714 PR714‡ PR714‡ PR714‡

[nm] 1045 1046 1047 1048 1050 1100 1232 1357 1410 0950 1050§ 1611

794 5.9188 5.9291 5.9270 5.9183 5.8818 6.1418 6.1388 6.2405

798 5.9432 5.9495 5.9514 5.9446 5.9050 6.1821 6.1790 6.2841

800 6.1389

802 5.9865 5.9975 5.9968 5.9935 5.9495 6.2311 6.2270 6.3307

806 6.0301 6.0406 6.0362 6.0318 5.9863 6.2685 6.2512 6.3602

810 6.0524 6.0629 6.0625 6.0629 6.2109 6.0056 6.2729 6.2607 6.3674

814 6.0615 6.0724 6.0686 6.0655 6.0047 6.2642 6.2480 6.3413

818 6.0724 6.0755 6.0754 6.0667 6.0078 6.2421 6.2320 6.3158

820 6.1722

822 6.0549 6.0617 6.0539 6.0481 5.9893 6.2073 6.1972 6.2860

826 6.0150 6.0297 6.0201 6.0190 5.9525 6.1591 6.1480 6.2357

830 5.9769 5.9963 5.9869 5.9816 6.0630 5.9115 6.1178 6.1047 6.1862

834 5.9320 5.9446 5.9391 5.9348 5.8653 6.0766 6.0584 6.1463

838 5.8906 5.8990 5.8936 5.8912 5.8276 6.0348 6.0175 6.1090

840 5.9524

842 5.8569 5.8669 5.8569 5.8541 5.7866 6.0097 5.9934 6.0821

846 5.8219 5.8327 5.8271 5.8218 5.7594 6.0002 5.9808 6.0699

850 5.8118 5.8221 5.8191 5.8141 5.9036 5.7581 5.9875 5.9854 6.0764

854 5.8067 5.8185 5.8181 5.8125 5.7509 5.9962 5.9920 6.0924

858 5.8384 5.8471 5.8395 5.8390 5.7760 6.0454 6.0277 6.1255

860 6.0167

862 5.8752 5.8831 5.8868 5.8790 5.8185 6.0778 6.0663 6.1733

866 5.9011 5.9121 5.9127 5.9070 5.8403 6.1045 6.0888 6.1958

870 5.9278 5.9409 5.9362 5.9328 6.0857 5.8631 6.1333 6.1146 6.2168

874 5.9480 5.9630 5.9595 5.9519 5.8781 6.1504 6.1316 6.2245

878 5.9434 5.9596 5.9549 5.9455 5.8745 6.1324 6.1073 6.2023

880 6.0560

882 5.9340 5.9468 5.9423 5.9317 5.8520 6.1094 6.0855 6.1717

886 5.9142 5.9257 5.9173 5.9107 5.8296 6.0742 6.0463 6.1382

890 5.8576 5.8658 5.8617 5.8538 5.9406 5.7711 6.0120 5.9842 6.0768

894 5.7345 5.7431 5.7478 5.7431 5.6548 5.8952 5.8593 5.9483

898 5.5523 5.5694 5.5656 5.5614 5.4810 5.7102 5.6755 5.7621

900 5.3204

902 5.3404 5.3523 5.3445 5.3393 5.2540 5.4807 5.4421 5.5376

906 5.1575 5.1685 5.1616 5.1489 5.0774 5.2924 5.2579 5.3482

910 5.1008 5.1083 5.1099 5.0957 5.1273 5.0188 5.2355 5.2031 5.2952

914 5.2625 5.2749 5.2706 5.2652 5.1846 5.4012 5.3779 5.4781

918 5.4713 5.4789 5.4815 5.4779 5.3964 5.6243 5.5990 5.7013

920 5.9934

922 5.6647 5.6716 5.6759 5.6609 5.5725 5.8198 5.7945 5.8786

926 5.7958 5.8058 5.8060 5.7949 5.7092 5.9485 5.9373 6.0238

930 5.8373 5.8543 5.8527 5.8393 6.0282 5.7523 5.9898 5.9826 6.0799

934 5.8178 5.8281 5.8271 5.8152 5.7241 5.9847 5.9858 6.0692

938 5.8376 5.8507 5.8552 5.8337 5.7642 6.0053 6.0115 6.0850

940 6.0221

942 5.8655 5.8910 5.8883 5.8810 5.7744 6.0292 6.0530 6.1317

† Denotes corrected radiances measured with the large PR714 aperture; all others were measured with the small aperture.

‡ Radiances measured on 23 June 1993; all other measurements were taken on 19 June 1993.

§ On 23 June, the 1050 PDT PR714 radiances were measured 20◦off axis.

89
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 16. (cont.) The CHORS sphere (four 275 Wlamps, all with apertures of 1.25) spectral radiance [μWcm−2 nm−1

sr−1] measured with the 746/ISIC, PR714, BSIXR, and SXR on 19 and 23 June 1993 (date and time given in PDT).

λ PR714 PR714† SXR PR714 PR714† BSIXR 746 SXR PR714 PR714‡ PR714‡ PR714‡

[nm] 1045 1046 1047 1048 1050 1100 1232 1357 1410 0950 1050§ 1611

946 5.8809 5.8974 5.8933 5.8974 5.7968 6.0470 6.0761 6.1425

950 5.9112 5.9100 5.9195 5.9271 6.0701 5.8309 6.0893 6.0987 6.1685

954 5.9366 5.9447 5.9481 5.9427 5.8584 6.1066 6.1108 6.1984

958 5.9769 6.0007 5.9862 5.9897 5.8935 6.1487 6.1394 6.2290

960 6.2051

962 6.0142 6.0284 6.0266 6.0274 5.9173 6.1890 6.1765 6.2754

966 6.0366 6.0474 6.0418 6.0504 5.9492 6.2146 6.2000 6.2843

970 6.0747 6.0790 6.0643 6.0729 6.3202 5.9746 6.2248 6.2227 6.3134

974 6.0708 6.0851 6.0791 6.0740 5.9763 6.2361 6.2340 6.3265

978 6.0961 6.1053 6.1065 6.0992 5.9939 6.2680 6.2649 6.3483

980 6.3125

982 6.1138 6.1364 6.1264 6.1161 6.0225 6.2890 6.2775 6.3845

986 6.1037 6.1173 6.1089 6.1193 6.0156 6.2818 6.2473 6.3730

990 6.0850 6.0822 6.0871 6.0893 6.2275 5.9835 6.2765 6.2283 6.3413

994 6.0466 6.0696 6.0645 6.0553 5.9595 6.2440 6.2083 6.3227

998 6.0316 6.0437 6.0400 6.0162 5.9308 6.1912 6.1765 6.2993

1000 6.1083

1002 5.9749 6.0037 5.9781 5.9864 5.8922 6.1508 6.1194 6.2378

1006 5.9299 5.9462 5.9383 5.9391 5.8355 6.1041 6.0695 6.1681

1010 5.8691 5.8708 5.8733 5.8778 5.7867 6.0268 6.0090 6.1155

1014 5.8056 5.8062 5.8180 5.8002 5.6950 5.9442 5.9401 6.0280

1018 5.7490 5.7878 5.7562 5.7358 5.6397 5.9253 5.8665 5.9706

1022 5.7353 5.7548 5.7280 5.7189 5.6071 5.8965 5.8438 5.9141

1026 5.7257 5.7255 5.7462 5.7284 5.6197 5.8677 5.8419 5.9376

1030 5.7305 5.7353 5.7614 5.7432 5.6347 5.8952 5.8571 5.9868

1034 5.7655 5.7771 5.7686 5.7681 5.6684 5.9340 5.8927 6.0157

1038 5.8200 5.8279 5.8003 5.8098 5.6989 5.9586 5.9369 6.0497

1042 5.8423 5.8220 5.8671 5.8360 5.7338 5.9869 5.9363 6.0169

1046 5.8312 5.8353 5.8580 5.8521 5.7099 5.9720 5.9628 6.0265

1050 5.8410 5.8382 5.8513 5.8103 5.7544 5.9514 6.0019 6.0638

1054 5.8744 5.8491 5.8734 5.8391 5.7408 6.0018 6.0645 6.0770

1058 5.8437 5.8785 5.8941 5.8090 5.7388 6.0138 6.0232 6.0568

1062 5.7390 5.8655 5.8339 5.8125 5.6895 5.9120 5.9194 6.0617

1066 5.8207 5.8110 5.8145 5.7846 5.6145 5.9447 5.8655 6.0905

1070 5.7769 5.7104 5.7056 5.7714 5.5704 5.9297 5.8337 5.9813

† Denotes corrected radiances measured with the large PR714 aperture; all others were measured with the small aperture.

‡ Radiances measured on 23 June 1993; all other measurements were taken on 19 June 1993.

§ On 23 June, the 1050 PDT PR714 radiances were measured 20◦off axis.

90
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 17. The UCSB sphere (illuminated with FEL lamp F303 at 50 cm) spectral radiance [μWcm−2 nm−1sr−1],

measured with the 746/ISIC, PR714 (large aperture; corrected), and the SXR on 21 June 1993. The PR714 measurement at 1822 PDT was taken with the UCSB sphere configured with a 2.54 cm entrance aperture; all others were

measured with a 5.08 cm entrance aperture.

λ 746 746 SXR PR714† PR714† PR714†

[nm] 1516 1520 1643 1657 1811 1822

350 0.0144 0.0131

360 0.0164 0.0166

370 0.0190 0.0191

380 0.0215 0.0224

382 0.0235 0.0236 0.0063

386 0.0267 0.0273 0.0071

390 0.0261 0.0263 0.0295 0.0297 0.0078

394 0.0329 0.0337 0.0088

398 0.0350 0.0363 0.0094

400 0.0309 0.0314

402 0.0376 0.0388 0.0101

406 0.0407 0.0418 0.0109

410 0.0363 0.0365 0.0436 0.0451 0.0117

411 0.0468

414 0.0464 0.0478 0.0125

418 0.0495 0.0509 0.0133

420 0.0423 0.0430

422 0.0524 0.0540 0.0141

426 0.0561 0.0579 0.0152

430 0.0627 0.0632 0.0595 0.0614 0.0161

434 0.0629 0.0648 0.0170

438 0.0664 0.0683 0.0179

440 0.0716 0.0720

441 0.0712

442 0.0707 0.0723 0.0190

446 0.0743 0.0762 0.0200

450 0.0818 0.0822 0.0778 0.0800 0.0210

454 0.0824 0.0846 0.0222

458 0.0861 0.0880 0.0231

460 0.0923 0.0926

462 0.0896 0.0916 0.0240

466 0.0940 0.0957 0.0251

470 0.1032 0.1037 0.0986 0.1001 0.0263

474 0.1031 0.1050 0.0276

478 0.1084 0.1100 0.0289

480 0.1150 0.1154

482 0.1128 0.1140 0.0299

486 0.1166 0.1178 0.0309

487 0.1217

490 0.1266 0.1270 0.1212 0.1224 0.0321

494 0.1261 0.1273 0.0334

498 0.1311 0.1320 0.0347

500 0.1385 0.1390

502 0.1356 0.1369 0.0359

† Denotes corrected radiances measured with the large PR714 aperture.

91
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 17. (cont.) The UCSB sphere (illuminated with FEL lamp F303 at 50 cm) spectral radiance [μWcm−2 nm−1

sr−1], measured with the 746/ISIC, PR714 (large aperture; corrected), and the SXR on 21 June 1993. The PR714

measurement at 1822 PDT was taken with the UCSB sphere configured with a 2.54 cm entrance aperture; all others

were measured with a 5.08 cm entrance aperture.

λ 746 746 SXR PR714† PR714† PR714†

[nm] 1516 1520 1643 1657 1811 1822

506 0.1396 0.1409 0.0370

510 0.1503 0.1510 0.1440 0.1451 0.0381

514 0.1491 0.1497 0.0394

518 0.1528 0.1537 0.0404

520 0.1621 0.1627

522 0.1576 0.1588 0.0416

526 0.1625 0.1637 0.0430

530 0.1757 0.1757 0.1670 0.1680 0.0441

534 0.1715 0.1723 0.0453

538 0.1766 0.1774 0.0466

540 0.1870 0.1880

542 0.1805 0.1816 0.0477

546 0.1847 0.1856 0.0487

547 0.1924

550 0.1982 0.1992 0.1893 0.1902 0.0499

554 0.1932 0.1941 0.0509

558 0.1979 0.1987 0.0522

560 0.2091 0.2100

562 0.2024 0.2034 0.0534

566 0.2070 0.2080 0.0546

570 0.2207 0.2207 0.2111 0.2121 0.0557

574 0.2153 0.2164 0.0568

578 0.2189 0.2199 0.0576

580 0.2307 0.2319

582 0.2217 0.2227 0.0583

586 0.2260 0.2271 0.0594

590 0.2411 0.2411 0.2304 0.2315 0.0607

594 0.2345 0.2358 0.0619

598 0.2394 0.2405 0.0631

600 0.2508 0.2516

602 0.2435 0.2444 0.0641

606 0.2459 0.2469 0.0649

610 0.2609 0.2617 0.2493 0.2505 0.0660

614 0.2524 0.2538 0.0667

618 0.2544 0.2560 0.0672

620 0.2706 0.2713

622 0.2584 0.2597 0.0681

626 0.2627 0.2637 0.0691

630 0.2795 0.2807 0.2663 0.2676 0.0702

634 0.2700 0.2714 0.0712

638 0.2728 0.2739 0.0719

640 0.2875 0.2883

642 0.2756 0.2770 0.0727

646 0.2783 0.2794 0.0734

650 0.2962 0.2970 0.2805 0.2813 0.0738

† Denotes corrected radiances measured with the large PR714 aperture.

92
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 17. (cont.) The UCSB sphere (illuminated with FEL lamp F303 at 50 cm) spectral radiance [μWcm−2 nm−1

sr−1], measured with the 746/ISIC, PR714 (large aperture; corrected), and the SXR on 21 June 1993. The PR714

measurement at 1822 PDT was taken with the UCSB sphere configured with a 2.54 cm entrance aperture; all others

were measured with a 5.08 cm entrance aperture.

λ 746 746 SXR PR714† PR714† PR714†

[nm] 1516 1520 1643 1657 1811 1822

654 0.2829 0.2837 0.0745

658 0.2855 0.2869 0.0752

660 0.3038 0.3046

661 0.3032

662 0.2902 0.2912 0.0763

666 0.2931 0.2943 0.0771

670 0.3111 0.3119 0.2958 0.2972 0.0777

674 0.2996 0.3006 0.0787

678 0.3020 0.3029 0.0794

680 0.3181 0.3190

682 0.3030 0.3039 0.0797

686 0.3041 0.3058 0.0802

690 0.3242 0.3251 0.3062 0.3078 0.0807

694 0.3068 0.3079 0.0809

698 0.3094 0.3105 0.0815

700 0.3303 0.3316

702 0.3125 0.3134 0.0823

706 0.3157 0.3162 0.0831

710 0.3369 0.3378 0.3192 0.3202 0.0841

714 0.3224 0.3236 0.0848

718 0.3245 0.3260 0.0853

720 0.3416 0.3426

722 0.3272 0.3282 0.0860

726 0.3290 0.3304 0.0867

730 0.3473 0.3482 0.3291 0.3302 0.0867

734 0.3305 0.3316 0.0869

738 0.3312 0.3322 0.0871

740 0.3524 0.3534

742 0.3290 0.3302 0.0866

746 0.3280 0.3291 0.0864

750 0.3569 0.3579 0.3302 0.3312 0.0870

754 0.3348 0.3359 0.0880

758 0.3388 0.3397 0.0891

760 0.3605 0.3615

762 0.3384 0.3395 0.0891

766 0.3394 0.3403 0.0892

770 0.3647 0.3656 0.3417 0.3427 0.0898

772 0.3576

774 0.3439 0.3450 0.0905

778 0.3447 0.3455 0.0908

780 0.3678 0.3688

782 0.3440 0.3451 0.0908

786 0.3443 0.3454 0.0909

790 0.3699 0.3710 0.3458 0.3469 0.0912

† Denotes corrected radiances measured with the large PR714 aperture.

93
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 17. (cont.) The UCSB sphere (illuminated with FEL lamp F303 at 50 cm) spectral radiance [μWcm−2 nm−1

sr−1], measured with the 746/ISIC, PR714 (large aperture; corrected), and the SXR on 21 June 1993. The PR714

measurement at 1822 PDT was taken with the UCSB sphere configured with a 2.54 cm entrance aperture; all others

were measured with a 5.08 cm entrance aperture.

λ 746 746 SXR PR714† PR714† PR714†

[nm] 1516 1520 1643 1657 1811 1822

794 0.3449 0.3459 0.0909

798 0.3444 0.3454 0.0909

800 0.3726 0.3737

802 0.3457 0.3469 0.0913

806 0.3466 0.3480 0.0917

810 0.3737 0.3748 0.3462 0.3477 0.0917

814 0.3468 0.3475 0.0918

818 0.3486 0.3493 0.0923

820 0.3738 0.3749

822 0.3477 0.3489 0.0921

826 0.3466 0.3476 0.0918

830 0.3758 0.3769 0.3490 0.3500 0.0924

834 0.3490 0.3502 0.0926

838 0.3477 0.3488 0.0923

840 0.3760 0.3760

842 0.3477 0.3491 0.0925

846 0.3491 0.3496 0.0929

850 0.3760 0.3772 0.3487 0.3495 0.0930

854 0.3482 0.3490 0.0929

858 0.3485 0.3493 0.0930

860 0.3768 0.3779

862 0.3474 0.3488 0.0929

866 0.3462 0.3476 0.0926

870 0.3758 0.3769 0.3469 0.3482 0.0926

874 0.3487 0.3497 0.0931

878 0.3485 0.3498 0.0934

880 0.3757 0.3767

882 0.3478 0.3491 0.0932

886 0.3476 0.3485 0.0932

890 0.3740 0.3750 0.3479 0.3489 0.0933

894 0.3495 0.3496 0.0936

898 0.3493 0.3503 0.0936

900 0.3734 0.3744

902 0.3456 0.3465 0.0928

906 0.3411 0.3422 0.0916

910 0.3715 0.3725 0.3348 0.3363 0.0900

914 0.3319 0.3323 0.0892

918 0.3316 0.3329 0.0892

920 0.3690 0.3700

922 0.3335 0.3346 0.0896

926 0.3343 0.3349 0.0898

930 0.3644 0.3654 0.3346 0.3348 0.0896

934 0.3329 0.3342 0.0894

938 0.3320 0.3330 0.0893

940 0.3607 0.3612

942 0.3308 0.3317 0.0890

† Denotes corrected radiances measured with the large PR714 aperture.

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 17. (cont.) The UCSB sphere (illuminated with FEL lamp F303 at 50 cm) spectral radiance [μWcm−2 nm−1

sr−1], measured with the 746/ISIC, PR714 (large aperture; corrected), and the SXR on 21 June 1993. The PR714

measurement at 1822 PDT was taken with the UCSB sphere configured with a 2.54 cm entrance aperture; all others

were measured with a 5.08 cm entrance aperture.

λ 746 746 SXR PR714† PR714† PR714†

[nm] 1516 1520 1643 1657 1811 1822

946 0.3303 0.3311 0.0889

950 0.3596 0.3606 0.3291 0.3304 0.0885

954 0.3264 0.3279 0.0880

958 0.3268 0.3280 0.0880

960 0.3580 0.3590

962 0.3266 0.3278 0.0880

966 0.3239 0.3253 0.0872

970 0.3562 0.3577 0.3231 0.3237 0.0869

974 0.3232 0.3234 0.0867

978 0.3230 0.3237 0.0869

980 0.3540 0.3550

982 0.3234 0.3239 0.0871

986 0.3227 0.3233 0.0869

990 0.3514 0.3525 0.3212 0.3221 0.0868

994 0.3216 0.3227 0.0866

998 0.3205 0.3219 0.0865

1000 0.3491 0.3503

1002 0.3192 0.3202 0.0861

1006 0.3202 0.3197 0.0860

1010 0.3190 0.3186 0.0855

1014 0.3171 0.3187 0.0853

1018 0.3146 0.3164 0.0846

1022 0.3147 0.3153 0.0846

1026 0.3136 0.3139 0.0841

1030 0.3121 0.3121 0.0839

1034 0.3090 0.3118 0.0836

1038 0.3113 0.3134 0.0841

1042 0.3090 0.3096 0.0835

1046 0.3044 0.3074 0.0818

1050 0.3051 0.3033 0.0814

1054 0.3068 0.3050 0.0821

1058 0.3066 0.3064 0.0822

1062 0.3026 0.3039 0.0825

1066 0.3062 0.3049 0.0837

1070 0.3030 0.3031 0.0816

† Denotes corrected radiances measured with the large PR714 aperture.

95
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 28. Spectral radiance of the UCSB sphere, illuminated by FEL lamp F303 at 50 cm from the entrance

aperture. Measured with a 5.08 cm entrance aperture with the 746/ISIC at 1516 and 1520 PDT, by the SXR at

1643 PDT (×), and by the PR714 at 1567 and 1811 PDT on 21 June 1993. Measured with a 2.54 cm entrance

aperture using the PR714 at 1822 PDT. The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of

the sphere, and the bottom panel illustrates the departures of the PR714 and SXR radiances (5.08 cm aperture

only) relative to the 1520 746/ISIC spectrum.

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

a

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 29. Spectral radiance of the WFF sphere, measured with the 746/ISIC (18 June; with open, No. 3, and

No. 5 apertures, in order of decreasing magnitude), the BSIXR (18 June; open), the PR714 and SXR (21 June;

with open, No. 3, No. 5, and No. 6 apertures in order of decreasing magnitude; 23 June; open aperture) [see

key above]. The top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1) of the sphere, and the bottom

panel illustrates the relative differences between the PR714, SXR, and 746/ISIC radiances at each aperture.

104
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

this magnitude from day to day, or whether some or all of

the spheres vary either spatially or temporally.

The extreme day-to-day variability of the CHORS

sphere may result (at least in part) from inadequate seasoning of the new 275 Wlamps. The lamps used in the

CHORS sphere demonstrate line structure, especially at

wavelengths above 700 nm, but to a lesser extent in the

visible range as well. Although the SIRREX-2 measurements suggest that the sphere can be used in this configuration to calibrate visible radiometer channels (assuming

a plaque or sphere transfer is made from a lamp irradiance

source), it is advisable to further modify the lamp housings

to accept seasoned lamps of a series known to be relatively

free from line structure. This upgrade will be done in early

1994.

The largest same-day differences (greater than 5%,

Fig. 28) were in the PR714, 746/ISIC, and SXR measurements of the UCSB sphere with external illumination. It

is very difficult to baffle all stray light between the lamp

and the spheres, and these discrepancies may result from

residual stray light contamination of the 746/ISIC irradiance measurements of the very low output from this sphere.

The PR714, SXR, and other narrow field-of-view radiometers, should be much less susceptible to stray light, and the

direction of the difference is compatible with this speculation. A third possible explanation for this large disagreement is that the radiance distribution in this sphere may

be extremely inhomogeneous.

OCR100 measurements of several of the spheres were

made by S. McLean of Satlantic. These measurements

were compared with the PR714, 746/ISIC, and SXR and

found similar magnitudes of between instrument discrepancies, with no suggestion of particularly better agreement

with any one of the other instruments. In short, these data

exhibit the same characteristics as those already described

and do not lead to any modifications in the results or conclusions. Therefore, they are not included specifically in

the figures or discussions for individual spheres.

In summary, the SIRREX-2 radiance scale transfer measurements for integrating spheres achieved only a 5–7% degree of internal consistency. In terms of uncertainty, this

represents no improvement over the results of SIRREX-1.

Nevertheless, the more extensive sequence of test experiments carried out during SIRREX-2 gives both a more

conclusive estimate of the uncertainties in the sources and

procedures in use today, and a better understanding of the

full scope of possible sphere and radiometer characteristics

which may contribute to the observed inconsistencies.

Temporal variations (either day to day, or on shorter

time scales following lamp warm up) in sphere illumination

could possibly have contributed to some of the observed

discrepancies. The new lamps in the CHORS sphere may

be especially suspect in this regard. Transfers to the GSFC

sphere, based on the irradiance scale of FEL lamp F269,

with the 746/ISIC on 15–19 June 1993 indicate that this

sphere is temporally stable within 1% (at least on a day-today basis); F269 and the 746/ISIC were not used to check

the GSFC sphere on subsequent days when measurements

with the PR714, SXR, and OCR100 indicate variability in

its radiance scale of approximately 3%.

Spatial, or angular, variability in radiance in the exit

port could also account for many aspects of the variability

measured with the PR714 and other narrow field-of-view

radiometers. Subsequent to SIRREX-2, the spatial uniformity of the GSFC sphere was determined (Appendix C).

These results, which show up to a 4% variability, significantly impact the SIRREX-2 measurements, apparently

limiting the uncertainty of any calibration made by the

GSFC sphere, using a calibrated transfer radiometer, to

about 4%. Such inhomogeneities may result from some

combination of either incomplete diffusion of lamp illumination in the sphere, or spatial variability of reflectance

in the wall coating material. Each time a narrow field-ofview radiometer is set up to view the sphere, it may see

a slightly different sub-area of the exit port, or possibly

view it from a slightly different angle. These phenomena

would not explain short-term variability in repeated measurements for a fixed instrument setup, but could explain

variations between setups (including instrument placement

and alignment, focus distance settings, and aperture settings). The extreme same-day, between instrument results

for the UCSB sphere may be especially suspect in this regard.

Sensitivity to stray light incident from angles outside a

radiometer’s nominal field-of-view also leads to errors and

variations. With the 746/ISIC irradiance measurement,

unbaffled stray light from angles beyond the exit port of

the source sphere clearly leads to a positive radiance error; the illumination configuration of the UCSB sphere

makes it especially difficult to completely eliminate this

source of error. With the narrow field-of-view radiometers

(PR714, SXR, OCR100, and BSIXR), out-of-field sensitivity creates a large aperture which may not be filled by

a sphere’s exit port area, and the degree of underfilling

will be sensitive to exact instrument placement, focus, etc.

This could lead to errors and variability between setups

which, on the basis of the SIRREX-2 measurements alone,

cannot be distinguished from radiance inhomogeneity in

the sphere. For example, NIST characterized the SXR

following SIRREX-2 and found significant stray light sensitivity to angles well beyond the instrument’s designed

2.5◦ field-of-view. Although the SIRREX-2 data were corrected accordingly, this size of source effect introduces uncertainties of up to 2% in some cases. (The SXR has since

been modified to eliminate this stray light sensitivity.) Adequate characterization data are not available for each of

the other small field-of-view instruments, and particularly

the PR714, to rule out this possible source of variability in

their data as well.

Temporal variations in the responsivity of a transfer radiometer is also a possible explanation for observed day-today and shorter interval variability in sphere radiance. The

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 19. The NOAA Optronics 420M sphere spectral radiance [μWcm−2 nm−1sr−1] measured with the SXR (small

aperture) and the PR714 (large aperture; corrected to the scale of the GSFC sphere) on 22 and 24 June 1993 (date

and time in PDT). Column indices correspond to the 420M settings: (1) D40,S3,W6 and (2) D100,S3,W5.

λ (1) (1) (1) (2) (1) (1)

[nm] PR714 SXR PR714 PR714 SXR PR714

1307† 1311† 1318† 1336† 0922 0930

382 0.0604 0.0597 0.0139 0.0595

386 0.0690 0.0689 0.0155 0.0698

390 0.0781 0.0765 0.0171 0.0769

394 0.0847 0.0850 0.0194 0.0853

398 0.0926 0.0919 0.0211 0.0927

402 0.1007 0.0996 0.0227 0.1002

406 0.1088 0.1092 0.0246 0.1077

410 0.1170 0.1175 0.0264 0.1174

411 0.1241 0.1221

414 0.1254 0.1259 0.0285 0.1260

418 0.1353 0.1355 0.0306 0.1352

422 0.1452 0.1445 0.0327 0.1445

426 0.1559 0.1555 0.0352 0.1551

430 0.1652 0.1654 0.0377 0.1650

434 0.1756 0.1759 0.0398 0.1762

438 0.1866 0.1864 0.0422 0.1867

441 0.2036 0.1974

442 0.1986 0.1991 0.0451 0.1988

446 0.2106 0.2104 0.0475 0.2100

450 0.2219 0.2208 0.0500 0.2207

454 0.2348 0.2342 0.0530 0.2336

458 0.2459 0.2457 0.0555 0.2458

462 0.2576 0.2574 0.0582 0.2578

466 0.2706 0.2707 0.0612 0.2700

470 0.2838 0.2844 0.0642 0.2840

474 0.2984 0.2984 0.0674 0.2978

478 0.3135 0.3138 0.0710 0.3134

482 0.3271 0.3270 0.0740 0.3275

486 0.3397 0.3400 0.0770 0.3399

487 0.3585 0.3397

490 0.3546 0.3543 0.0803 0.3540

494 0.3701 0.3702 0.0837 0.3696

498 0.3851 0.3866 0.0874 0.3862

502 0.4014 0.4014 0.0910 0.4012

506 0.4149 0.4138 0.0940 0.4144

510 0.4302 0.4304 0.0974 0.4301

514 0.4459 0.4460 0.1011 0.4454

518 0.4601 0.4598 0.1041 0.4598

522 0.4778 0.4770 0.1079 0.4769

526 0.4936 0.4948 0.1120 0.4939

530 0.5090 0.5096 0.1154 0.5095

534 0.5256 0.5254 0.1190 0.5251

538 0.5432 0.5431 0.1231 0.5426

542 0.5583 0.5579 0.1265 0.5583

546 0.5739 0.5749 0.1299 0.5733

† Measurements taken on 22 June 1993; all other measurements were taken on 24 June 1993.

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Table 19. (cont.) The NOAA Optronics 420M sphere spectral radiance [μWcm−2 nm−1sr−1] measured with the

SXR (small aperture) and the PR714 (large aperture; corrected to the scale of the GSFC sphere) on 22 and 24 June

1993 (date and time in PDT). Column indices correspond to the 420M settings: (1) D40,S3,W6 and (2) D100,S3,W5.

λ (1) (1) (1) (2) (1) (1)

[nm] PR714 SXR PR714 PR714 SXR PR714

1307† 1311† 1318† 1336† 0922 0930

547 0.6052 0.5514

550 0.5907 0.5916 0.1339 0.5908

554 0.6058 0.6072 0.1371 0.6066

558 0.6233 0.6235 0.1411 0.6235

562 0.6407 0.6412 0.1452 0.6397

566 0.6581 0.6577 0.1491 0.6565

570 0.6743 0.6735 0.1529 0.6734

574 0.6912 0.6919 0.1568 0.6900

578 0.7050 0.7063 0.1600 0.7049

582 0.7182 0.7196 0.1628 0.7187

586 0.7356 0.7359 0.1667 0.7351

590 0.7536 0.7537 0.1708 0.7536

594 0.7711 0.7708 0.1746 0.7707

598 0.7887 0.7889 0.1790 0.7886

602 0.8060 0.8060 0.1829 0.8057

606 0.8186 0.8193 0.1856 0.8185

610 0.8329 0.8334 0.1889 0.8327

614 0.8485 0.8480 0.1922 0.8472

618 0.8593 0.8601 0.1946 0.8596

622 0.8758 0.8760 0.1983 0.8749

626 0.8928 0.8930 0.2022 0.8917

630 0.9113 0.9096 0.2065 0.9098

634 0.9277 0.9265 0.2102 0.9264

638 0.9397 0.9409 0.2128 0.9395

642 0.9537 0.9531 0.2159 0.9534

646 0.9661 0.9667 0.2189 0.9652

650 0.9751 0.9751 0.2212 0.9751

654 0.9886 0.9877 0.2243 0.9877

658 1.0020 1.0011 0.2273 1.0011

661 1.0670 0.9711

662 1.0200 1.0191 0.2314 1.0181

666 1.0346 1.0356 0.2348 1.0346

670 1.0481 1.0501 0.2377 1.0501

674 1.0651 1.0661 0.2418 1.0661

678 1.0779 1.0789 0.2448 1.0789

682 1.0872 1.0872 0.2464 1.0872

686 1.0966 1.0957 0.2484 1.0957

690 1.1074 1.1064 0.2506 1.1045

694 1.1140 1.1150 0.2524 1.1121

698 1.1260 1.1260 0.2555 1.1240

702 1.1403 1.1393 0.2587 1.1373

706 1.1536 1.1546 0.2619 1.1526

710 1.1714 1.1734 0.2662 1.1714

714 1.1897 1.1908 0.2700 1.1877

718 1.2034 1.2034 0.2730 1.2024

† Measurements taken on 22 June 1993; all other measurements were taken on 24 June 1993.

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 19. (cont.) The NOAA Optronics 420M sphere spectral radiance [μWcm−2 nm−1sr−1] measured with the

SXR (small aperture) and the PR714 (large aperture; corrected to the scale of the GSFC sphere) on 22 and 24 June

1993 (date and time in PDT). Column indices correspond to the 420M settings: (1) D40,S3,W6 and (2) D100,S3,W5.

λ (1) (1) (1) (2) (1) (1)

[nm] PR714 SXR PR714 PR714 SXR PR714

1307† 1311† 1318† 1336† 0922 0930

722 1.2158 1.2178 0.2766 1.2158

726 1.2287 1.2297 0.2795 1.2277

730 1.2342 1.2351 0.2805 1.2322

734 1.2438 1.2429 0.2833 1.2429

738 1.2507 1.2517 0.2854 1.2498

742 1.2493 1.2522 0.2851 1.2484

746 1.2516 1.2525 0.2855 1.2506

750 1.2651 1.2670 0.2890 1.2641

754 1.2896 1.2906 0.2944 1.2877

758 1.3121 1.3121 0.2996 1.3111

762 1.3179 1.3179 0.3010 1.3139

766 1.3252 1.3262 0.3029 1.3233

770 1.3354 1.3383 0.3058 1.3354

772 1.4006 1.3613

774 1.3473 1.3493 0.3086 1.3463

778 1.3553 1.3563 0.3103 1.3534

782 1.3574 1.3594 0.3110 1.3564

786 1.3639 1.3639 0.3127 1.3620

790 1.3704 1.3734 0.3143 1.3684

794 1.3719 1.3739 0.3145 1.3699

798 1.3753 1.3763 0.3150 1.3733

802 1.3835 1.3845 0.3175 1.3815

806 1.3911 1.3921 0.3194 1.3882

810 1.3966 1.3976 0.3205 1.3937

814 1.4018 1.4028 0.3215 1.3998

818 1.4106 1.4116 0.3239 1.4087

822 1.4130 1.4159 0.3245 1.4110

826 1.4148 1.4167 0.3244 1.4128

830 1.4236 1.4265 0.3272 1.4207

834 1.4288 1.4317 0.3280 1.4268

838 1.4295 1.4314 0.3279 1.4285

842 1.4338 1.4368 0.3292 1.4329

846 1.4380 1.4410 0.3311 1.4370

850 1.4413 1.4453 0.3321 1.4413

854 1.4436 1.4456 0.3324 1.4416

858 1.4467 1.4497 0.3332 1.4446

862 1.4485 1.4505 0.3333 1.4475

866 1.4480 1.4520 0.3334 1.4480

870 1.4542 1.4583 0.3349 1.4532

874 1.4622 1.4653 0.3374 1.4622

878 1.4662 1.4692 0.3382 1.4662

882 1.4696 1.4726 0.3387 1.4686

886 1.4717 1.4747 0.3392 1.4707

890 1.4742 1.4792 0.3401 1.4762

894 1.4844 1.4904 0.3423 1.4854

† Measurements taken on 22 June 1993; all other measurements were taken on 24 June 1993.

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Table 19. (cont.) The NOAA Optronics 420M sphere spectral radiance [μWcm−2 nm−1sr−1] measured with the

SXR (small aperture) and the PR714 (large aperture; corrected to the scale of the GSFC sphere) on 22 and 24 June

1993 (date and time in PDT). Column indices correspond to the 420M settings: (1) D40,S3,W6 and (2) D100,S3,W5.

λ (1) (1) (1) (2) (1) (1)

[nm] PR714 SXR PR714 PR714 SXR PR714

1307† 1311† 1318† 1336† 0922 0930

898 1.4902 1.4932 0.3437 1.4912

902 1.4793 1.4833 0.3413 1.4803

906 1.4642 1.4672 0.3380 1.4623

910 1.4407 1.4446 0.3325 1.4398

914 1.4319 1.4357 0.3301 1.4328

918 1.4338 1.4386 0.3311 1.4357

922 1.4440 1.4489 0.3334 1.4440

926 1.4549 1.4569 0.3349 1.4529

930 1.4591 1.4621 0.3365 1.4581

934 1.4603 1.4623 0.3363 1.4563

938 1.4587 1.4617 0.3361 1.4547

942 1.4565 1.4605 0.3357 1.4575

946 1.4550 1.4590 0.3367 1.4560

950 1.4544 1.4564 0.3361 1.4554

954 1.4495 1.4505 0.3343 1.4475

958 1.4504 1.4544 0.3349 1.4504

962 1.4500 1.4521 0.3353 1.4480

966 1.4415 1.4435 0.3333 1.4405

970 1.4407 1.4447 0.3330 1.4407

974 1.4382 1.4463 0.3330 1.4392

978 1.4444 1.4475 0.3334 1.4434

982 1.4473 1.4503 0.3335 1.4452

986 1.4452 1.4523 0.3339 1.4472

990 1.4418 1.4509 0.3344 1.4479

994 1.4447 1.4467 0.3349 1.4478

998 1.4435 1.4476 0.3350 1.4466

1002 1.4423 1.4443 0.3342 1.4413

1006 1.4417 1.4499 0.3339 1.4478

1010 1.4412 1.4432 0.3334 1.4422

1014 1.4418 1.4418 0.3325 1.4337

1018 1.4284 1.4354 0.3300 1.4284

1022 1.4267 1.4367 0.3304 1.4277

1026 1.4239 1.4309 0.3309 1.4239

1030 1.4192 1.4192 0.3280 1.4182

1034 1.4139 1.4149 0.3261 1.4139

1038 1.4214 1.4164 0.3274 1.4204

1042 1.4120 1.4150 0.3269 1.4110

1046 1.3927 1.4075 0.3212 1.3936

1050 1.3849 1.4118 0.3231 1.4058

1054 1.3998 1.4008 0.3248 1.4149

1058 1.4152 1.3978 0.3232 1.3978

1062 1.3818 1.3951 0.3191 1.3889

1066 1.3982 1.4043 0.3224 1.4063

1070 1.3751 1.3893 0.3180 1.3781

† Measurements taken on 22 June 1993; all other measurements were taken on 24 June 1993.

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 30. Spectral radiance of the NOAA Optronics 420M sphere, measured with the PR714 on 22 June

(D100,S3,W5) and 24 June (D40,S3,W5), and with the SXR on 22 June (o) and 24 June (×) (D40,S3,W6). The

top panel illustrates spectral radiance (μWcm−2 nm−1 sr−1), and the bottom panel illustrates the differences

between the D40,S3,W6 radiance spectra measured on 22 June, relative to that measured on 24 June.

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

746/ISIC responsivity was independently determined with

lamp F269 for each measurement setup, so it can be excluded in this regard. However, the PR714 was calibrated

using the GSFC sphere radiance scale (confirmed with the

746/ISIC and lamp F269) on 19 June 1993, and this responsivity scale was applied to all measurements with that

instrument throughout SIRREX-2. Temporal drift in the

spectral responsivity of the PR714 offers a very plausible

explanation for many of the measured differences.

Taken together, these results and possible explanations

can only be resolved if all SIRREX spheres are fully characterized for spatial and angular homogeneity and temporal

stability, and if all SIRREX transfer radiometers are fully

characterized for angular field-of-view and geometric stray

light rejection, out-of-band stray light rejection, and temporal stability of spectral responsivity. This work should

form a central focus for the SIRREX activity in 1994, with

the ultimate objective of obtaining an uncertainty of 1%

in spectral radiance scale realizations. An uncertainty of

1% for all surface measurements is the goal for verifying an

uncertainty of 5% in the SeaWiFS measurements of normalized water-leaving radiance.

4. PLAQUE REFLECTANCE

At the majority of the SIRREX laboratories, reflectance

plaques are used to convert known spectral irradiance from

a lamp to calculated spectral radiance, for fixed angles of

illumination and reflection when the plaque is viewed by

a narrow field-of-view spectral radiometer. In some cases,

this composite FEL lamp and plaque source of spectral

radiance is used directly to calibrate a field radiometer.

In other cases, it is used to calibrate a stable transfer radiometer, which may then be used to transfer the radiance

scale to an integrating sphere, which can provide a larger

and more uniform source of diffuse radiance (Section 3.0

above).

At NIST, GSFC, and UA, small pressed Halon plaques

are made as primary standards of known reflectance. At

all SIRREX laboratories, however, plaques used in routine laboratory and field measurements are fabricated from

Spectralon, a sintered version of Halon, available commercially from Labsphere, Inc. For comparison at SIRREX-2,

large Spectralon plaques were contributed by CHORS, BSI,

UCSB, and Satlantic, and small plaques were contributed

by BSI, UCSB, and NOAA (see Appendix A for plaque

specifications).

4.1 Methods

FEL lamp 91349B (with the lamp masked by a circular

baffle; Table 2) was aligned carefully at 150.0 cm normal

to one of the Spectralon plaques, which was mounted in

a kinematic holder at the end of the CHORS optical bar.

The PR714 spectroradiometer (large aperture setting) was

aligned to view the center of the plaque at 45.0◦ from normal at an approximate distance of 1.5 m.

Lamp 91349B was warmed up for 20 minutes prior to

beginning the measurements. Spectral radiance reflected

at 45◦ was measured with the PR714, based on the calibration transferred from the GSFC sphere on 19 June

1993 (Tables 6 and 7). The other plaques were then substituted sequentially into the kinematic mount holder until

the spectral reflectance of all seven plaques were measured.

4.2 Results

Spectral (0◦, 45◦) bidirectional reflectances calculated

from the above measurements of the eight plaques are

listed in Table 20 and illustrated in Fig. 31. Standard

deviations, σ, are less than 1% at all wavelengths, and are

less than 0.5% at wavelengths greater than 438 nm.

4.3 Discussion and Conclusions

The apparent plaque reflectance spectra illustrated in

Fig. 31 all show spectral features which are common to the

PR714 spectral responsivity calibration function, as determined from the GSFC sphere on 19 June 1993 (Fig. 18). In

this regard, note the especially strong similarity in the oscillatory features near 400 nm and near 725 nm in Figs. 18

and 31. This feature suggests that the spectral features

in Fig. 31 are an artifact of the responsivity assumed for

the PR714, and further leads to the suspicion that these results may also be contaminated by drift in the responsivity

of the instrument between its calibration on 19 June and

these measurements on 25 June. If the radiance measurements were accurate, the occurrence of reflectances greater

than 1 could be explained by a specular component in (0◦,

45◦) plaque reflectance. Given the above noted uncertainty

regarding the PR714, however, it must be concluded that

these particular measurements of apparent (0◦, 45◦) BRDF

are not sufficiently reliable for use in irradiance to radiance

transfers from FEL lamps.

The approximate 1% envelope in apparent reflectance

functions for several different Spectralon plaques does support the assumption that these plaques are effectively interchangeable, once valid BRDF measurements are realized.

5. VOLTMETERS AND SHUNTS

Voltmeters and precision shunt resistors were intercompared on 24 June 1993. Voltmeters, manufacturers, models, and owners are:

Owner Manufacturer Model S/N

GSFC Fluke 8842A 561078

UA HP3457 2538A02159

Satlantic HP34401A 3146A09840

CHORS HP34401A 3146A08065

NOAA HP34401A 3146A14453

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Table 20. The spectral reflectance (π × L/E) (0◦, 45◦) for several Spectralon plaques. The owner and size of each

square plaque is listed at the top of each column. Note that the large CHORS plaque was run twice—once with the

other large plaques, and then again with the small plaques for cross reference. The average of columns 1–8 is listed as

F ̄.

λ Large Plaques Small Plaques

[nm] BSI CHORS Satlantic UCSB CHORS† BSI NOAA UCSB F σ  ̄

382 0.9477 0.9356 0.9315 0.9438 0.9263 0.9447 0.9450 0.9320 0.9383 0.0079

386 1.0023 0.9905 0.9767 0.9885 0.9841 0.9994 1.0014 0.9901 0.9916 0.0090

390 1.0070 0.9959 0.9908 1.0095 0.9984 1.0037 1.0111 1.0072 1.0030 0.0072

394 1.0379 1.0256 1.0204 1.0426 1.0271 1.0345 1.0383 1.0334 1.0325 0.0075

398 1.0370 1.0193 1.0117 1.0327 1.0184 1.0337 1.0352 1.0224 1.0263 0.0095

402 1.0197 1.0053 1.0016 1.0142 1.0019 1.0152 1.0182 1.0103 1.0108 0.0072

406 1.0109 1.0009 0.9948 1.0069 1.0003 1.0070 1.0076 1.0015 1.0037 0.0052

410 1.0064 0.9948 0.9858 1.0024 0.9952 1.0063 1.0032 0.9985 0.9991 0.0070

414 1.0040 0.9891 0.9810 0.9969 0.9896 1.0024 0.9977 0.9945 0.9944 0.0076

418 1.0034 0.9934 0.9853 0.9992 0.9905 1.0008 0.9997 0.9950 0.9959 0.0060

422 1.0045 0.9939 0.9883 1.0006 0.9910 1.0024 1.0005 0.9955 0.9971 0.0058

426 1.0161 1.0059 0.9984 1.0116 1.0022 1.0131 1.0109 1.0059 1.0080 0.0059

430 1.0175 1.0079 1.0013 1.0148 1.0070 1.0149 1.0125 1.0097 1.0107 0.0053

434 1.0189 1.0103 1.0033 1.0159 1.0073 1.0157 1.0145 1.0110 1.0121 0.0051

438 1.0207 1.0138 1.0061 1.0167 1.0119 1.0187 1.0177 1.0148 1.0151 0.0046

442 1.0293 1.0210 1.0155 1.0265 1.0192 1.0284 1.0255 1.0228 1.0235 0.0048

446 1.0274 1.0195 1.0152 1.0257 1.0169 1.0257 1.0239 1.0222 1.0221 0.0044

450 1.0226 1.0143 1.0101 1.0193 1.0109 1.0210 1.0167 1.0167 1.0164 0.0045

454 1.0248 1.0168 1.0121 1.0224 1.0144 1.0224 1.0192 1.0192 1.0189 0.0044

458 1.0192 1.0124 1.0079 1.0177 1.0102 1.0155 1.0147 1.0132 1.0138 0.0038

462 1.0139 1.0075 1.0039 1.0125 1.0054 1.0117 1.0096 1.0096 1.0093 0.0035

466 1.0142 1.0074 1.0047 1.0135 1.0054 1.0128 1.0108 1.0094 1.0098 0.0037

470 1.0166 1.0114 1.0075 1.0153 1.0075 1.0140 1.0127 1.0127 1.0122 0.0033

474 1.0201 1.0158 1.0119 1.0189 1.0126 1.0182 1.0170 1.0164 1.0164 0.0029

478 1.0260 1.0211 1.0180 1.0248 1.0186 1.0242 1.0217 1.0229 1.0222 0.0029

482 1.0252 1.0187 1.0163 1.0234 1.0163 1.0228 1.0205 1.0210 1.0205 0.0033

486 1.0207 1.0158 1.0130 1.0213 1.0136 1.0185 1.0169 1.0174 1.0171 0.0030

490 1.0215 1.0168 1.0152 1.0210 1.0152 1.0204 1.0173 1.0184 1.0182 0.0025

494 1.0256 1.0200 1.0185 1.0251 1.0185 1.0231 1.0205 1.0221 1.0217 0.0028

498 1.0277 1.0227 1.0213 1.0287 1.0213 1.0262 1.0237 1.0257 1.0247 0.0029

502 1.0283 1.0240 1.0216 1.0292 1.0225 1.0268 1.0249 1.0254 1.0253 0.0027

506 1.0232 1.0204 1.0177 1.0242 1.0181 1.0223 1.0195 1.0209 1.0208 0.0024

510 1.0221 1.0194 1.0172 1.0240 1.0172 1.0208 1.0194 1.0213 1.0202 0.0023

514 1.0241 1.0211 1.0189 1.0254 1.0189 1.0219 1.0202 1.0223 1.0216 0.0023

518 1.0206 1.0168 1.0164 1.0218 1.0152 1.0181 1.0164 1.0185 1.0180 0.0023

522 1.0237 1.0205 1.0189 1.0249 1.0193 1.0221 1.0201 1.0221 1.0215 0.0021

526 1.0260 1.0233 1.0217 1.0288 1.0217 1.0249 1.0229 1.0257 1.0244 0.0025

530 1.0243 1.0216 1.0205 1.0265 1.0197 1.0231 1.0212 1.0239 1.0226 0.0023

534 1.0237 1.0219 1.0207 1.0263 1.0200 1.0230 1.0207 1.0245 1.0226 0.0021

538 1.0263 1.0241 1.0227 1.0292 1.0230 1.0245 1.0223 1.0259 1.0247 0.0024

542 1.0251 1.0226 1.0212 1.0276 1.0219 1.0229 1.0212 1.0237 1.0233 0.0022

546 1.0248 1.0231 1.0210 1.0268 1.0217 1.0234 1.0210 1.0241 1.0232 0.0020

550 1.0261 1.0244 1.0225 1.0284 1.0231 1.0248 1.0228 1.0264 1.0248 0.0021

554 1.0244 1.0232 1.0212 1.0276 1.0212 1.0238 1.0209 1.0244 1.0233 0.0022

558 1.0259 1.0247 1.0234 1.0287 1.0234 1.0247 1.0225 1.0253 1.0248 0.0020

562 1.0272 1.0263 1.0245 1.0303 1.0245 1.0254 1.0239 1.0269 1.0261 0.0020

566 1.0278 1.0271 1.0256 1.0314 1.0253 1.0256 1.0241 1.0278 1.0268 0.0022

† Denotes the CHORS plaque that was run a second time for cross reference with the small plaques.

112
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table 20. (cont.) Spectral reflectance (π × L/E) for several Spectralon plaques. The owner and size of each square

plaque is listed at the top of each column. Note that the large CHORS plaque was run twice—once with the other

large plaques, and then again with the small plaques for cross reference. The average of columns 1–8 is listed as F ̄.

λ Large Plaques Small Plaques

[nm] BSI CHORS Satlantic UCSB CHORS† BSI NOAA UCSB F σ  ̄

570 1.0274 1.0265 1.0250 1.0309 1.0262 1.0253 1.0244 1.0271 1.0266 0.0021

574 1.0284 1.0287 1.0258 1.0325 1.0272 1.0269 1.0255 1.0290 1.0280 0.0022

578 1.0248 1.0253 1.0231 1.0290 1.0242 1.0239 1.0222 1.0259 1.0248 0.0021

582 1.0208 1.0211 1.0194 1.0246 1.0192 1.0197 1.0178 1.0211 1.0205 0.0020

586 1.0226 1.0218 1.0204 1.0258 1.0207 1.0207 1.0196 1.0226 1.0218 0.0020

590 1.0249 1.0246 1.0238 1.0285 1.0231 1.0228 1.0207 1.0249 1.0242 0.0022

594 1.0260 1.0268 1.0260 1.0304 1.0250 1.0240 1.0225 1.0266 1.0259 0.0022

598 1.0295 1.0310 1.0295 1.0340 1.0287 1.0280 1.0260 1.0310 1.0297 0.0024

602 1.0311 1.0328 1.0301 1.0358 1.0306 1.0294 1.0276 1.0319 1.0312 0.0024

606 1.0277 1.0291 1.0267 1.0323 1.0267 1.0250 1.0240 1.0284 1.0275 0.0026

610 1.0264 1.0269 1.0260 1.0308 1.0264 1.0250 1.0231 1.0274 1.0265 0.0022

614 1.0244 1.0270 1.0256 1.0299 1.0256 1.0239 1.0222 1.0263 1.0256 0.0023

618 1.0205 1.0222 1.0208 1.0261 1.0215 1.0194 1.0179 1.0222 1.0213 0.0024

622 1.0223 1.0244 1.0226 1.0269 1.0230 1.0205 1.0200 1.0230 1.0228 0.0022

626 1.0258 1.0276 1.0258 1.0301 1.0258 1.0245 1.0227 1.0267 1.0261 0.0022

630 1.0293 1.0315 1.0289 1.0337 1.0298 1.0273 1.0255 1.0300 1.0295 0.0025

634 1.0310 1.0338 1.0314 1.0358 1.0312 1.0292 1.0277 1.0319 1.0315 0.0025

638 1.0284 1.0316 1.0302 1.0336 1.0297 1.0274 1.0255 1.0299 1.0295 0.0025

642 1.0286 1.0311 1.0288 1.0326 1.0297 1.0263 1.0251 1.0301 1.0290 0.0024

646 1.0271 1.0296 1.0273 1.0317 1.0290 1.0250 1.0232 1.0281 1.0276 0.0026

650 1.0218 1.0251 1.0227 1.0276 1.0233 1.0204 1.0182 1.0235 1.0228 0.0029

654 1.0214 1.0241 1.0224 1.0271 1.0208 1.0200 1.0182 1.0224 1.0221 0.0027

658 1.0203 1.0241 1.0223 1.0261 1.0219 1.0195 1.0175 1.0229 1.0218 0.0027

662 1.0255 1.0285 1.0263 1.0306 1.0275 1.0251 1.0225 1.0273 1.0267 0.0025

666 1.0282 1.0316 1.0286 1.0330 1.0304 1.0263 1.0255 1.0294 1.0291 0.0026

670 1.0292 1.0335 1.0307 1.0342 1.0321 1.0282 1.0265 1.0311 1.0307 0.0026

674 1.0342 1.0384 1.0365 1.0394 1.0377 1.0327 1.0312 1.0358 1.0357 0.0028

678 1.0350 1.0386 1.0375 1.0393 1.0373 1.0333 1.0317 1.0360 1.0361 0.0026

682 1.0305 1.0353 1.0344 1.0355 1.0334 1.0294 1.0270 1.0318 1.0322 0.0030

686 1.0267 1.0318 1.0316 1.0314 1.0307 1.0262 1.0233 1.0291 1.0289 0.0031

690 1.0261 1.0317 1.0297 1.0311 1.0302 1.0245 1.0228 1.0279 1.0280 0.0033

694 1.0220 1.0277 1.0258 1.0275 1.0268 1.0206 1.0186 1.0243 1.0242 0.0035

698 1.0222 1.0290 1.0271 1.0280 1.0272 1.0212 1.0199 1.0244 1.0249 0.0034

702 1.0256 1.0321 1.0306 1.0306 1.0306 1.0237 1.0226 1.0274 1.0279 0.0036

706 1.0295 1.0361 1.0340 1.0341 1.0349 1.0279 1.0265 1.0309 1.0317 0.0035

710 1.0359 1.0431 1.0413 1.0409 1.0426 1.0352 1.0332 1.0382 1.0388 0.0037

714 1.0410 1.0488 1.0472 1.0465 1.0480 1.0410 1.0383 1.0437 1.0443 0.0039

718 1.0443 1.0508 1.0503 1.0492 1.0503 1.0423 1.0404 1.0464 1.0467 0.0041

722 1.0484 1.0546 1.0541 1.0532 1.0547 1.0469 1.0446 1.0502 1.0508 0.0039

726 1.0499 1.0568 1.0551 1.0544 1.0570 1.0485 1.0463 1.0520 1.0525 0.0040

730 1.0451 1.0534 1.0510 1.0495 1.0517 1.0442 1.0422 1.0483 1.0482 0.0040

734 1.0463 1.0531 1.0510 1.0503 1.0523 1.0446 1.0430 1.0488 1.0487 0.0037

738 1.0442 1.0507 1.0489 1.0483 1.0496 1.0429 1.0406 1.0471 1.0465 0.0036

742 1.0339 1.0409 1.0390 1.0388 1.0395 1.0328 1.0312 1.0369 1.0366 0.0036

746 1.0280 1.0348 1.0326 1.0324 1.0335 1.0269 1.0249 1.0302 1.0304 0.0035

750 1.0326 1.0379 1.0354 1.0365 1.0365 1.0301 1.0281 1.0335 1.0338 0.0034

† Denotes the CHORS plaque that was run a second time for cross reference with the small plaques.

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The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Fig. 31. The spectral reflectance of several Spectralon reflectance plaques belonging to institutions (which

are square in shape) are indicated in the curve legend above. These reflectance estimates are calculated from

spectral radiance measurements with the PR714, viewing the center of each plaque at 45◦ incidence while the

plaque was illuminated by lamp 91349 (with a circular baffle) at a distance of 150.0 cm normal to the plaque

center.

114
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

The shunts; their manufacturers, either Leeds & Northrup

(L&N) or Weston; the models used; and their respective

owners are:

Owner Manufacturer Model S/N

GSFC L&N 4222B 1921670

NOAA Weston GS125†

CHORS Weston 0042211

CHORS L&N 4385 1630135

Satlantic L&N C100 1192

† Cat# 0042210

The shunts were connected in series with lamp F269

with the CHORS Optronics 83DS supply at 8.000 A and

resulting voltage drops were measured with each voltmeter.

All of the HP34401A voltmeters disagreed by 20 μV (2 mA)

and disagreed by 40 μV (4 mA) when the polarity was reversed to read the negative voltages from the shunts. This

difference was attributed to an AC voltage across each

shunt, causing a common mode AC which was not rejected

by the HP34401 meters, although it was properly rejected

by the Fluke 8842A and the HP3457. The total AC output

measured across the lamp was found to be 400 mV rms at

120 Hz which indicates some power supply leakage. The

shunt currents were measured with the GSFC voltmeter.

The voltmeters were compared measuring across the GSFC

shunt. Voltages measured across the GSFC shunt by each

of the voltmeters are:

Owner Manufacturer Voltages [mV]

GSFC Fluke 8842A 80.001

UA HP3457 79.997

Satlantic HP34401A 79.981

CHORS HP34401A 79.980

NOAA HP34401A 79.980

Voltage drops measured with the GSFC voltmeter across

each shunt are:

Owner Manufacturer Voltages [mV]

GSFC L&N 4222B 80.001

NOAA Weston 80.007

CHORS Weston 79.919

CHORS L&N 4385 80.007

Satlantic L&N C100 80.006

The CHORS Weston shunt is a previously uncalibrated

spare. All other shunt readings match their calibrated values within the specified uncertainty of 0.01%.

To verify that the AC voltage was the source of the

voltmeter disagreement, a precision DC reference was assembled using a REF-02 chip, and its output was measured

with each voltmeter. The comparisons between all of the

voltmeters were within 10 μV in 5 V (0.0002%). The voltmeters were also compared with F269 using the GSFC Optronics 83DS supply and the GSFC shunt, showing agreement within 8 μV (0.8 mA). This particular supply showed

only 0.8 mV rms of AC across the lamp.

6. SUMMARY AND CONCLUSIONS

This report completes the analyses of the principal data

sets acquired during SIRREX-2. The key results are:

1. The NIST (October 1992) spectral irradiance scale

of FEL lamp F269 was transferred to FEL lamps

used at the participating laboratories with an uncertainty better than 1% (Section 2). It is recommended that the scales of spectral irradiance listed

here be used with these lamps for all radiometric

calibrations associated with the SeaWiFS program.

2. The transfer of the spectral radiance scale of the

GSFC sphere, as determined using lamp F269, to

the integrating sphere sources used by the other

laboratories was determined with an overall uncertainty of 5% or larger. Possible sources of these

discrepancies include inadequate characterization of

temporal stability and homogeneity of radiance in

each sphere (see Appendix C), and of geometric

stray light and temporal stability of spectral responsivity characteristics of the transfer radiometers used in these measurements.

3. Spectral (0◦, 45◦) BRDF estimates for several Spectralon plaques used at various SIRREX laboratories, while internally consistent between plaques,

appear to be contaminated by the possibly variable wavelength dependent calibration factors of the

PR714 spectroradiometer used for these measurements during SIRREX-2. SIRREX measurements

have not yet succeeded in confirming or refining

the manufacturer’s reflectance calibrations for these

plaques.

4. Shunts and voltmeters available at the SIRREX laboratories for measuring lamp current during radiometric calibrations are within the necessary uncertainty specifications. An exception is that the relatively new model HP34401A multimeters (recently

purchased by several laboratories) do not accurately

measure shunt voltage supplied by the Optronics

83DS power supply, due to this meter’s sensitivity

to the AC ripple produced by that supply’s current

regulation circuitry.

The principal conclusions and recommendations based

on the SIRREX-2 results are:

a. Lamp sources of spectral irradiance used for calibrations by SIRREX participants are now on a common

scale with an uncertainty of less than 1%, which is

consistent with the SeaWiFS goals for radiometric

accuracy. In the interests of economy, future interlaboratory checks of these lamps should be carried

out at GSFC on a mail exchange basis. The scales

of two FEL lamps at each laboratory should be

115
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

checked at GSFC on an annual basis. The GSFC

lamps should be recalibrated at NIST on a routine

basis—at least once every two years.

b. The approximately 5% uncertainty of intercomparisons between spectral radiance scales of SIRREX

integrating sphere sources is not consistent with the

SeaWiFS goals for radiometric accuracy. To improve this situation in 1994, the following changes

are recommended: 1) all SIRREX spheres must be

characterized for temporal stability and homogeneity of radiance, and 2) the geometric stray light,

the out-of-band rejection, and the temporal stability (in terms of spectral responsivity characteristics) of transfer radiometers used to intercompare

the spheres must be accurately determined. Sources

with substandard characteristics, such as the recently measured nonuniformity of the GSFC sphere

(Appendix C) must be corrected. The necessary

characterizations of the NIST SXR have been completed, but similar characterizations must be performed on a spectroradiometer (to be identified)

capable of measuring sphere radiance scales with

much finer spectral resolution than can be achieved

with the SXR. Sphere and radiometer characterizations must be effected at each individual laboratory

prior to intercomparisons during SIRREX-3 sometime in mid-1994.

c. A second major objective of SIRREX-3 will be to

accurately characterize the (0◦, 45◦) BRDF of Spectralon plaques used by SIRREX participants. Procedures and equipment to be used in this characterization should be defined early in 1994.

d. In parallel with characterizations of spectral irradiance and radiance sources to be used for SeaWiFS

radiometric calibrations, the 1994 SIRREX activities should extend to round-robin instrument calibration exchanges to test the internal consistency of

calibrations performed independently at the participating laboratories. Detailed procedures for these

blind comparisons remain to be defined, but the

essence will be to sequentially calibrate individual

radiometers at two or more laboratories within the

space of a few weeks, and to then compare the

results to determine the uncertainty of radiometric calibrations performed throughout the SIRREX

community.

e. Detailed analysis of the measurement uncertainties

associated with all of the procedures described here

must be completed.

Appendices

A. Instruments calibrated at SIRREX-2

B. Attendees to SIRREX-2

C. Uniformity of the GSFC Sphere

Appendix A

Instruments calibrated at SIRREX-2

Table A-1 (next page) lists the pertinent information regarding the spheres and plaques which were calibrated at SIRREX-2.

Appendix B

Attendees to SIRREX-2

The attendees to SIRREX-2 are presented alphabetically.

Gregg Adelman

Biospherical Instruments, Inc.

5340 Riley Street

San Diego, CA 92110

Voice: 602–686–1888

Fax: 602–686–1887

Ros Austin

SDSU/CHORS/Suite 206

6505 Alvarado Road

San Diego, CA 92120–5005

Voice: 619–594–2244

Fax: 619–594–4570

Internet: raustin@chors.sdsu.edu

Stuart Biggar

University of Arizona

1600 N. Country Club, Suite 100

Tuscon, AZ 85716

Voice: 602–621–4242

Fax: 602–621–8292

Internet: stu@spectra.opt-sci.arizona.edu

Rocky Booth

Biospherical Instruments, Inc.

5340 Riley Street

San Diego, CA 92110

Voice: 602–686–1888

Fax: 602–686–1887

Internet: booth@ssurf.ucsd.edu

Dennis Clark

NOAA/NESDIS

E/RA 28, WWB, Rm. 104

Washington, DC 20233

Voice: 301–763–8102

Fax: 301–763–8020

Omnet: d.clark.noaa

John Cooper

NASA/GSFC/Code 925

Greenbelt, MD 20771

Voice: 301–286–1210

Fax: 301–286–1616

Internet: cooper@pacf.dnet.nasa.gov

Chris Cromer

NIST/Bldg. 221, Room B208

Gaithersburg, MD 20899

Voice: 301–975–3216

Fax: 301–840–8551

Internet: cromer@garnet.nist.gov

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J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Table A-1. Organizations who participated in the June 1993 SIRREX and their intercalibration and

radiometric sources.

Organization Contact Lamps Sphere Plaque† Radiometer

BSI R. Booth F310 50.8 cm (20 in) 43.2 cm (17 in) [Large] BSIXR

G. Adelman F321 25.4 cm (10 in) [Small]

91357

CHORS J. Mueller 90572 102 cm (40 in) 43.2 cm (17 in) [Large]

R. Austin 91348

C. Titus 91534

91349

91533

GSFC J. McLean F227 107 cm (42 in) Optronics 746/ISIC

J. Cooper F268

F269

F315

NIST C. Johnson PTFE 5.08 cm (2 in) PR714

C. Cromer SXR

NOAA D. Clark F307 Optronics 420M 25.4 cm (10 in) [Small]

F308

NRIFSF K. Kawasaki F123

Satlantic S. McLean 91591 43.2 cm (17 in) [Large] OCR100 (s/n 26)

91604

91615

SBRC J. Young§ DXW19

UA S. Biggar F296 UAXR

F297

UCSB D. Menzies F219 50.8 cm (20 in) 43.2 cm (17 in) [Large] OCR100 (s/n 9, 11)

F303 25.4 cm (10 in) [Small]

F304

F305

UM K. Voss§ F12G

F12H

WFF S. Manizade 76.2 cm (30 in)

†All plaques used are square and are made of Spectralon with the exception of the NIST plaque, which is round (dimension

given is the diameter) and is made of pressed polytetrafluoroethylene (PTFE).

§Did not attend.

Mike Feinholz

Moss Landing Marine Laboratory

PO Box 450

Moss Landing, CA 95039

Voice: 408–755–8675

Fax: 408–753–2826

Internet: feinholz@mlml.calstate.edu

Tom Gentile

NIST/Bldg. 221, Room B208

Gaithersburg, MD 20899

Voice: 301–975–2325

Fax: 301–869–5700

Internet: gentile@garnet.nist.gov

Stanford Hooker

NASA/GSFC/Code 970.2

Greenbelt, MD 20771

Voice: 301–286–9503

Fax: 301–286–1775

Omnet: s.hooker

Internet: stan@ardbeg.gsfc.nasa.gov

Carol Johnson

NIST/Bldg. 221, Room A221

Gaithersburg, MD 20899

Voice: 301–975–2322

Fax: 301–869–5700

Internet: cjohnson@enh.nist.gov

Kiyoshi Kawasaki

Natl. Res. Inst. of Far Seas Fish.

5–7–1 Orido

Shimizu, Shizuoka, 424

JAPAN

Voice: 81–543–34–0715

Fax: 81–543–35–9642

Telex: 03965689 FARSEA J

Omnet: k.kawasaki

Dan Kennedy

NRL/Code 7331

Stennis Space Center, MS 39529

Voice: 601–688–4979

Fax: 601–688–5997

117
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

Serdar Manizade

NASA/GSFC/WFF

Bldg. N159

Wallops Island, VA 23337

Voice: 804–824–1025

Fax: 804–824–2343

Fax: 804–824–1036

Internet: manizade@aol3.wff.nasa.gov

Jim McLean

NASA/GSFC/Code 925

Greenbelt, MD 20771

Voice: 301–286–8134

Fax: 301–286–1616

GSFCmail: jmclean

Scott McLean

Satlantic, Inc.

Richmond Terminal Pier 9

3295 Barrington Street

Halifax, B3K5X8 Nova Scotia

CANADA

Voice: 902–492–4780

Fax: 902–492–4781

Internet: scott@predator.ocean.dal.ca

Dave Menzies

CRSEO/UCSB

Santa Barbara, CA 93106

Voice: 805–893–8496

Fax: 805–893–2578

Internet: davem@crseo.ucsb.edu

James Mueller

SDSU/CHORS/Suite 206

6505 Alvarado Road

San Diego, CA 92120–5005

Voice: 619–594–2230

Fax: 619–594–4570

Omnet: j.mueller

Internet: jmueller@chors.sdsu.edu

Tom Peacock

USF/Dept. of Marine Science

140 Seventh Avenue, South

St. Petersburg, FL 33701–5016

Voice: 813–893–9148

Fax: 813–893–9189

Clay Titus

SDSU/CHORS/Suite 206

6505 Alvarado Road

San Diego, CA 92120–5005

Voice: 619–594–2244

Lab: 619–594–4830

Fax: 619–594–4570

Internet: ctitus@chors.sdsu.edu

Todd Westphal

NASA/GSFC/GSC/Code 970.2

Greenbelt, MD 20771

Voice: 301–286–9975

Fax: 301–286–1775

Internet: twest@calval.gsfc.nasa.gov

Mark Yarbrough

Moss Landing Marine Laboratory

PO Box 450

Moss Landing, CA 95039

Voice: 408–755–8685

Fax: 408–755–8686

Internet: yarbrough@nsf.mlml.sdsu.calstate.edu

Appendix C

Uniformity of the GSFC Sphere

The spatial distribution of the spectral radiance of the GSFC

sphere was studied after SIRREX-2; the distribution is asymmetric and the variations are significant when compared to the

1% uncertainty that is required for spectral radiance measurements in support of the SeaWiFS program.

Two independent measurements were done. Using a radiometer consisting of an achromatic lens, a filter, and a silicon

photodiode, NASA mapped the spectral radiance in the exit

port of the integrating sphere (Fig. C-1). The horizontal and

vertical axes are labeled in terms of the stepping motor position;

20 counts corresponds to 2 cm. These data were normalized to

the value recorded at the central position, and show a total variation of up to 4%. Using the SXR on March 4, 1994, NIST and

NASA measured the spectral radiance in the exit port of the

sphere for all of the SXR channels. The target area was about

37 mm. A single horizontal scan was acquired at the central

vertical position. These results are shown in Fig. C-2, but now

the data are normalized to the average value for each channel.

The variation is about 3.5%, and except for the red channel at

772 nm, there is little spectral dependence in the variation.

The magnitude of these variations is greater than what is

consistent with the SeaWiFS program goals, since the different

transfer radiometers have various field-of-views, and GSFC realizes spectral radiance by averaging over the exit aperture of

the sphere. The asymmetry of the variation introduces sensitivity to alignment, and in the case of some multichannel transfer

radiometers, orientation. To meet the program goals, it must

be possible to repeatedly measure spheres using transfer radiometers without regard to alignment issues.

Glossary

AC Alternating Current

BRDF Bidirectional Reflectance Distribution Function

BSI Biospherical Instruments, Incorporated

BSIXR BSI’s Transfer Radiometer

CHORS Center for Hydro-Optics and Remote Sensing

DXW Not an acronym, but a lamp designator.

FEL Not an acronym, but a lamp designator.

GLOBEC Global Ecosystem

GSFC Goddard Space Flight Center

ISIC Integrating Sphere Irradiance Collector

JGOFS Joint Global Ocean Flux Study

L&N Leeds & Northrup

MLML Moss Landing Marine Laboratory

118
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Fig. C-1. The mapped spectral radiance in the exit port of the integrating sphere. The horizontal and vertical axes are

labeled in terms of the stepping motor position; 20 counts corresponds to 2 cm.

Fig. C-2. GSFC sphere uniformity normalized to average for the channel.

119
The Second SeaWiFS Intercalibration Round-Robin Experiment, SIRREX-2, June 1993

NASA National Aeronautics and Space Administration

NRIFSF National Research Institute of Far Seas Fisheries

(Japan)

NIST National Institute of Standards and Technology

NOAA National Oceanic and Atmospheric Administration

PDT Pacific Daylight Time

PR Photo Research

PTFE Polytetrafluoroethylene

QED Quantum Efficient Device

rms root mean square

SBRC (Hughes) Santa Barbara Research Center

SDSU San Diego State University

SeaWiFS Sea-viewing Wide Field-of-view Sensor

SI Syst`eme International d’ Unit`es or International

System of Units

SIRREX SeaWiFS Intercalibration Round-Robin Experiment

SIRREX-1 The First SIRREX (July 1992)

SIRREX-2 The Second SIRREX (June 1993)

SIRREX-3 The Third SIRREX (to be held in 1994)

S/N Serial Number

SXR SeaWiFS Transfer Radiometer

UA University of Arizona

UAXR University of Arizona’s Transfer Radiometer

UCSB University of California at Santa Barbara

UM University of Miami

WFF Wallops Flight Facility (NASA)

Symbols

δ Relative difference

E(λ) Spectral irradiance.

Emeas(λ) Measured radiance.

Eref (λ) Reference radiance.

F ̄ Arithmetic average.

F(λ) Calibration factor.

F  ̄(λ) Average of calibration factors.

Fi Correction factor.

L(λ) Spectral radiance.

Pi PR714 raw radiance.

λ Wavelength.

σ Standard deviation.

References

McClain, C.R., W.E. Esaias, W. Barnes, B. Guenther, D. Endres, S.B. Hooker, G. Mitchell, and R. Barnes, 1992a: Calibration and Validation Plan for SeaWiFS. NASA Tech.

Memo. 104566, Vol. 3, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 41 pp.

Mueller, J.L., 1993: The First SeaWiFS Intercalibration RoundRobin Experiment, SIRREX-1, July 1992. NASA Tech.

Memo. 104566, Vol. 14, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 60 pp.

Mueller, J.L., and R.W. Austin, 1992: Ocean Optics Protocols. NASA Tech. Memo. 104566, Vol. 5, S.B. Hooker and

E.R. Firestone, Eds., NASA Goddard Space Flight Center,

Greenbelt, Maryland, 45 pp.

Walker, J.H., R.D. Saunders, J.K. Jackson, and D.A. McSparron., 1987: Spectral Irradiance Calibrations. NBS Special

Publication 250-20, U.S. Department of Commerce, National Bureau of Standards, Washington, DC., 37 pp. plus

Appendices.

The SeaWiFS Technical Report Series

Vol. 1

Hooker, S.B., W.E. Esaias, G.C. Feldman, W.W. Gregg, and

C.R. McClain, 1992: An Overview of SeaWiFS and Ocean

Color. NASA Tech. Memo. 104566, Vol. 1, S.B. Hooker

and E.R. Firestone, Eds., NASA Goddard Space Flight

Center, Greenbelt, Maryland, 24 pp., plus color plates.

Vol. 2

Gregg, W.W., 1992: Analysis of Orbit Selection for SeaWiFS:

Ascending vs. Descending Node. NASA Tech. Memo.

104566, Vol. 2, S.B. Hooker and E.R. Firestone, Eds.,

NASA Goddard Space Flight Center, Greenbelt, Maryland, 16 pp.

Vol. 3

McClain, C.R., W.E. Esaias, W. Barnes, B. Guenther, D. Endres, S. Hooker, G. Mitchell, and R. Barnes, 1992: Calibration and Validation Plan for SeaWiFS. NASA Tech.

Memo. 104566, Vol. 3, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 41 pp.

Vol. 4

McClain, C.R., E. Yeh, and G. Fu, 1992: An Analysis of GAC

Sampling Algorithms: A Case Study. NASA Tech. Memo.

104566, Vol. 4, S.B. Hooker and E.R. Firestone, Eds.,

NASA Goddard Space Flight Center, Greenbelt, Maryland, 22 pp., plus color plates.

Vol. 5

Mueller, J.L., and R.W. Austin, 1992: Ocean Optics Protocols. NASA Tech. Memo. 104566, Vol. 5, S.B. Hooker and

E.R. Firestone, Eds., NASA Goddard Space Flight Center,

Greenbelt, Maryland, 43 pp.

Vol. 6

Firestone, E.R., and S.B. Hooker, 1992: SeaWiFS Technical

Report Series Summary Index: Volumes 1–5. NASA Tech.

Memo. 104566, Vol. 6, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 9 pp.

Vol. 7

Darzi, M., 1992: Cloud Screening for Polar Orbiting Visible

and IR Satellite Sensors. NASA Tech. Memo. 104566, Vol.

7, S.B. Hooker and E.R. Firestone, Eds., NASA Goddard

Space Flight Center, Greenbelt, Maryland, 7 pp.

120
J. Mueller, C. Johnson, C. Cromer, J. Cooper, J. McLean, S. Hooker, and T. Westphal

Vol. 8

Hooker, S.B., W.E. Esaias, and L.A. Rexrode, 1993: Proceedings of the First SeaWiFS Science Team Meeting. NASA

Tech. Memo. 104566, Vol. 8, S.B. Hooker and E.R. Firestone, Eds., NASA Goddard Space Flight Center, Greenbelt, Maryland, 61 pp.

Vol. 9

Gregg, W.W., F.C. Chen, A.L. Mezaache, J.D. Chen, J.A.

Whiting, 1993: The Simulated SeaWiFS Data Set, Version 1. NASA Tech. Memo. 104566, Vol. 9, S.B. Hooker

and E.R. Firestone, Eds., NASA Goddard Space Flight

Center, Greenbelt, Maryland, 17 pp.

Vol. 10

Woodward, R.H., R.A. Barnes, C.R. McClain, W.E. Esaias,

W.L. Barnes, and A.T. Mecherikunnel, 1993: Modeling of

the SeaWiFS Solar and Lunar Observations. NASA Tech.

Memo. 104566, Vol. 10, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 26 pp.

Vol. 11

Patt, F.S., C.M. Hoisington, W.W. Gregg, and P.L. Coronado,

1993: Analysis of Selected Orbit Propagation Models for

the SeaWiFS Mission. NASA Tech. Memo. 104566, Vol.

11, S.B. Hooker, E.R. Firestone, and A.W. Indest, Eds.,

NASA Goddard Space Flight Center, Greenbelt, Maryland, 16 pp.

Vol. 12

Firestone, E.R., and S.B. Hooker, 1993: SeaWiFS Technical Report Series Summary Index: Volumes 1–11. NASA Tech.

Memo. 104566, Vol. 12, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 28 pp.

Vol. 13

McClain, C.R., K.R. Arrigo, J. Comiso, R. Fraser, M. Darzi,

J.K. Firestone, B. Schieber, E-n. Yeh, and C.W. Sullivan, 1994: Case Studies for SeaWiFS Calibration and Validation, Part 1. NASA Tech. Memo. 104566, Vol. 13,

S.B. Hooker and E.R. Firestone, Eds., NASA Goddard

Space Flight Center, Greenbelt, Maryland, 52 pp., plus

color plates.

Vol. 14

Mueller, J.L., 1993: The First SeaWiFS Intercalibration RoundRobin Experiment, SIRREX-1, July 1992. NASA Tech.

Memo. 104566, Vol. 14, S.B. Hooker and E.R. Firestone,

Eds., NASA Goddard Space Flight Center, Greenbelt,

Maryland, 60 pp.

Vol. 15

Gregg, W.W., F.S. Patt, R.H. Woodward, 1994: The Simulated SeaWiFS Data Set, Version 2. NASA Tech. Memo.

104566, Vol. 15, S.B. Hooker and E.R. Firestone, Eds.,

NASA Goddard Space Flight Center, Greenbelt, Maryland, 42 pp., plus color plates.

Vol. 16

Mueller, J.L., B.C. Johnson, C.L. Cromer, J.W. Cooper, J.T.

McLean, S.B. Hooker, and T.L. Westphal, 1994: The Second SeaWiFS Intercalibration Round-Robin Experiment,

SIRREX-2, June 1993. NASA Tech. Memo. 104566, Vol.

16, S.B. Hooker and E.R. Firestone, Eds., NASA Goddard

Space Flight Center, Greenbelt, Maryland, 121 pp.

121
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4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

 SeaWiFS Technical Report Series

 Volume 16–The Second SeaWiFS Intercalibration Round-Robin Experiment, Code 900

SIRREX-2, June 1993

 James T. McLean, Stanford B. Hooker, and Todd L. Westphal

 Series Editors: Stanford B. Hooker and Elaine R. Firestone

6. AUTHOR(S)

 James L. Mueller, B. Carol Johnson, Christopher L. Cromer, John W. Cooper,

Laboratory for Hydrospheric Processes

Goddard Space Flight Center 94B00081

Greenbelt, Maryland 20771

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11. SUPPLEMENTARY NOTES

12a. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

 James L. Mueller: CHORS/San Diego State University, San Diego, California; B. Carol Johnson and

 Christopher L. Cromer: National Institute of Standards and Technology; John W. Cooper: Hughes STX,

 Lanham, Maryland; and Todd L. Westphal and Elaine R. Firestone: General Sciences Corporation, Laurel, Maryland

13. ABSTRACT (Maximum 200 words)

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SeaWiFS, Oceanography, SIRREX-2, Lamps Standards, Sphere Sources, Plaque 121

Report is available from the Center for AeroSpace Information (CASI),

7121 Standard Drive, Hanover, MD 21076–1320; (301)621-0390

This report presents the results of the second Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Intercalibration

Round-Robin Experiment (SIRREX-2), which was held at the Center for Hydro-Optics and Remote Sensing (CHORS)

at San Diego State University (SDSU) on 14–25 June 1993. SeaWiFS is an ocean color radiometer that is scheduled for launch in 1994.

The SIRREXs are part of the SeaWiFS Calibration and Validation Program that includes the National Aeronautics and Space Administration's (NASA) Goddard Space Flight Center (GSFC), CHORS, the National Institute of Standards and Technology (NIST), and

several other laboratories. GSFC maintains the radiometric scales (spectral radiance and irradiance) for the SeaWiFS program using

spectral irradiance standard lamps, which are calibrated by NIST. The purpose of each SIRREX is to assure that the radiometric scales

which are realized by the laboratories who participate in the SeaWiFS Calibration and Validation Program are correct; that is, the uncertainties of the radiometric scales are such that measurements of normalized water-leaving radiance using oceanographic radiometers

have uncertainties of 5%. SIRREX-1 demonstrated, from the internal consistency of the results, that the program goals would not be

met without improvements to the instrumentation. The results of SIRREX-2 demonstrate that spectral irradiance scales realized using

the GSFC standard irradiance lamp (F269) are consistent with the program goals, as the uncertainty of these measurements is assessed

to be about 1%. However, this is not true for the spectral radiance scales, where again the internal consistency of the results is used to

assess the uncertainty. This is attributed to inadequate performance and characterization of the instrumentation. For example, spatial

nonuniformities, spectral features, and sensitivity to illumination configuration were observed in some of the integrating sphere sources.

The results of SIRREX-2 clearly indicate the direction for future work, with the main emphasis on instrument characterization and the

assessment of the measurement uncertainties so that the results may be stated in a more definitive manner.

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