NASA

Technical

Memorandum

NASA TM - 10839?

CALIBRATION, NAVIGATION, AND REGISTRATION

OF MAMS DATA FOR FIFE

By G. J. Jedlovec and R. J. Atkinson

Space Science Laboratory

Science and Engineering Directorate

February 1993

TM

(NASA-_.-I083@7) CALIBRATIONp

NAVIGATIJN, AND REGISTRATION OF

MAMS DATA FOR FIFE (NASA) 56 p

N93-22599

Unclas

G3/43 0153103

[U/tgA

National Aeronautics and

Space Administration

George C. Marshall Space Flight Center

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Ffbrnarv 1993 TPehnical M,,morandnm

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Calibration, Navigation, and Registration of MAMS Data for FIFE

6. AUTHOR(S)

G. J. Jedlovec and R. J. Atkinson*

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

George C. Marshall Space Flight Center

Marshall Space Flight Center, AL 35812

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, D.C. 20546

8. PERFORMING ORGANIZATION

REPORT NUMBER

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

NASA TM- 108397

11.SUPPLEMENTARYNOTES

Prepared by Space Science Laboratory, Science & Engineering Directorate.

*General Electric Company, Huntwill% Alabama

12a.DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified--Unlimited

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The International Satellite Land Surface Climatology Project (ISLSCP) was conducted to study the interaction

of the atmosphere with the land surface and the research problems associated with the interpretation of satellite

data over the Earth's land surface. The experimental objectives of the First ISLSCP Field Experiment (FIFE)

were the simultaneous acquisition of satellite, atmospheric, and surface data and to use these data to understand

the processes controlling energy/mass exchange at the surface. The experiment site is a 15 x 15 km area

southeast of Manhattan, Kansas, intersected by Interstate 70 and Kansas highway 177. The Konza Prairie

portion is 5 x 5 km and is a controlled experiment site consisting primarily of native tall grass prairie vegetation.

The remainder of the site is grazing and farm land with trees along creek beds that are scattered over the area.

Airborne multispectral imagery from the Multispectral Atmospheric Mapping Sensor (MAMS) was collected

over this region on two days during Intensive Field Campaign -1 (IFC-1) to study the time and space variability

of remotely-seused geophysical parameters. These datasets consist of multiple overflights covering about a 60-

min period during late morning on June 4, 1987, and shortly after dark on the following day. Image data from

each overpass were calibrated and Earth located with respect to each other using aircraft inertial navigation

system parameters and ground control points. These were the first MAMS flights made with 10-bit thermal

data.

14. SUBJECT TERMS

_u%MS, First ISLSCP Field Experiment, FIFE, Meteorology, Remote

Sensing, Navigation, Calibration

17. SECURITYCLASSIFICATION18. SECURITYCLASSIFICATION19.

OF REPORT OF THISPAGE

Unclassified Unclassified

NSN 7540-01-280-5500

SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

15. NUMBER OF PAGES

56

16. PRICE CODE

NTIS

20. LIMITATION OF ABSTR,_CT

Unlimited

Standard Form 298 (Rev 2-89)
ACKNOWLEDGMENTS

Significant editorial and other contributions were made by Anthony

Guillory/MSFC. His efforts are greatly appreciated. Portions of this work were

performed under the Physical Climate and Hydrologic Systems research program at

NASA Headquarters. The support of the MAMS flights for FIFE by Dr. James

Dodge is greatly appreciated. The collection of the MAMS data was also possible

because of the dedicated efforts of various NASA Ames Research Center personnel,

including the instrument technicians, U2 flight crew and pilots.

ii
TABLE OF CONTENTS Page

INTRODUCTION ....................................... 1

Applications of the MAMS ............................... 1

Purpose of MAMS Flights During FIFE ....................... 1

BACKGROUND ........................................ 3

Instrument Description . . . 3

MAMS FIFE Data ..................................... 7

CALIBRATION ........................................ 12

Visible Channels ...................................... 12

Infrared Channels ..................................... 13

NAVIGATION ......................................... 16

Data Sources ........................................ 16

The Algorithm ....................................... 17

Navigation Correction Using Landmarks ....................... 17

Navigation Correction During Remapping ...................... 20

Universal Transverse Mercator (UTM) Grid System ................ 28

projection Formulas ........................ 30

FIS DATASET ........................................ 34

Data Quality ........................................ 34

JOURNAL OF GEOPHYSICAL RESEARCH (JGR) DATASET .......... 37

SUMMARY .......................................... 38

REFERENCES ........................................ 39

APPENDIX ........................................... 41

,°,

111
Figure

1

2

3

4

5

6

LIST OF ILLUSTRATIONS

Title Page

MAMS scan geometry ............... _.................. 4

MAMS flight tracks over the FIFE study region ................. 9

Aircraft roll data from INS and MAMS data streams .............. 18

Landmark-determined and INS headings ...................... 21

Landmark-determined headings and corrected regression fit of headings.. 23

Regression fit of pitch with spurious readings ignored ............. 26

7 Displacements after remapping FIFE passes" 1 and 2 into UTM

coordinates ....................................... 27

8 Transverse Mercator projection geometry ..................... 29

A1 MAMS raw imagery ................................. 42

iv
Table

1

2

LIST OF TABLES

Title Page

Selected Multispectral Scanner Characteristics .................. 5

Comparison of Satellite Thermal Channel Characteristics

with that of MAMS .................................. 6

3 Standard MAMS Instrument Configuration .................... 8

4 Channel Sensitivities and Sample Noise Estimates for MAMS Channels for

FIFE on June 4, 1987 ................................. 11

5 Landmark RMS Errors ................................ 25

6 FIS Data Coverage Region ............................. 35

7 MAMS FIS Data .................................... 36

V
i
TECHNICAL MEMORANDUM

CALIBRATION, NAVIGATION, AND REGISTRATION OF MAMS DATA

FOR FIFE

INTRODUCTION

NASA developed severai aircraft sensors in the mid 1980's to verify data from

new satellite sensors and to collect unique datasets that would serve to justify future

space-based instruments on low-Earth and geostationary observation platforms. In

1985, the Multispectral Atmospheric Mapping Sensor (MAMS) was developed and

flown to verify small-scale water vapor features observed in Visible Infrared Spin

Scan Radiometer (VISSR) Atmospheric Sounder (VAS) imagery on the

Geosynchronous Operational Environmental Satellites (GOES). This aircraft sensor

provided a unique opportunity to independently verify single pixel variations observed

in the VAS channels (Menzel et al., 1986). This verification continued for several

years providing useful correlative measurements (Jedlovec et al., 1986b; Moeller et

al., 1990).

Applications of the MAMS

The MAMS 6.5 micrometer channel has been used to map variations in upper

tropospheric water vapor associated with a variety of atmospheric disturbances

(Menzel et al., 1986; JedIovec et al., 1986b). The split window channels at I I and

12 #m allow surface temperature estimations and the determination of the total

integrated water content in a column of the atmosphere as discussed by Jedlovec

(1987, 1990). The MAMS has also been used to study geomorphology along the Gulf

of Mexico coast. Reflectances in the visible and near infrared channels of MAMS

have been used to estimate suspended sediment concentrations, their source regions,

and spatial distribution. Data from a series of flights before and after passage of

weather systems have enhanced the understanding of the role that these systems play

in producing geomorphic changes (Moeller et al., 1989). A time sequence of

multispectral imagery along the coast of California was collected in October of 1989

to investigate the feasibility of determining ocean motions by tracking features in the

water. MAMS data have been collected over Mt. Mitchell, North Carolina to detect

and monitor the effects of pollution on forest decline in the region.

Purpose of MAMS Flights During FIFE

In 1987, a series of flights was initiated to collect several unique datasets which

capture the spatial and temporal variability of atmospheric and surface geophysical

parameters important to small-scale hydrologic and energy processes of the surface

and lower atmosphere. A secondary goal was to study the problems with remote
sensingof geophysicalparametersfrom geostationaryorbit, particularly with respect

to thechangingsatellite-Sunviewing geometries. Theseflights includedseveralover

the FIFE region. The specificgoalsof the FIFE flights were to investigatethe

thermalvariability of the surfaceovera highly instrumentedground-truthsite, its

relationto surfacefeatures,land use,and soil moisture,andto studythe effectof

different Sun-sensorviewing geometrieson thevisible and reflectedinfrared

measurements.The abovegoalsalso addressedseveralof the FIFE scientific

objectives,particularly thosedealingwith thecorrectionandcalibrationof remotelysenseddata,and the measurementof reflectedand emittedradiancesfor biological

processstudies(SellersandHall, 1987).

The datacollectedwith MAMS over theFIFE regionprovide uniquevisible and

infrared measurementsof the atmosphereandunderlyingsurfaceat time and space

scalescurrently not availablefrom satellites. This documentdescribesthe MAMS

datasetfor FIFE, thedataquality, spatialresolution,datacoverage,and the

calibrationand navigationproceduresemployed. A comprehensiveanalysisof the

MAMS thermal datahasbeenperformedand usedto studythe relationshipbetween

surfacethermalparametersand surfacefeaturesas representedby their NDVI values.

A review of MAMS-derivedgeophysicalparametersfor FIFE is presentedin Jedlovec

andAtkinson (1992).

2
BACKGROUND

The aircraft remote sensing data used in this investigation are from the airborne

Multispectral Atmospheric Mapping Sensor (MAMS) (Jedlovec et al., 1986a, 1989).

MAMS is a multispectral scanner that measures reflected radiation from the Earth's

surface and clouds in eight visible and near infrared bands, and thermal emission

from the earth's surface, clouds, and atmospheric constituents (primarily water vapor)

in three of four available infrared bands.

Instrument Description

The MAMS scan geometry is shown in Figure 1. The instrument was flown on a

NASA U2 high-altitude aircraft during FIFE at a nominal altitude of 20 km, and

provided a horizontal ground resolution for each field-of-view of about 100 m at

nadir. From this altitude, the width of the entire cross path field-of-view scanned by

the sensor was roughly 37 km and provided detailed resolution of atmospheric and

surface features across the swath width and along the aircraft flight track.

The MAMS design was based on that of other instruments developed by Daedalus

Enterprises, Inc. for visible and infrared mapping. It shares the same scan head,

digitizer, tape system, and supporting electronics as other Daedalus airborne scanners

for the NASA high altitude aircraft. The difference lies in the spectrometer channels,

particularly in the infrared region (Jedlovec et al., 1986a). The prism used to

disperse the incident energy into the visible and near infrared channels is identical to

that of the airborne Thematic Mapper Simulator (TMS). The use of the 5.0 taRa

aperture in the standard MAMS configuration, however, changes the spectral

characteristics of the near infrared channels slightly as shown in Table 1. This

difference does not significantly affect the use of the MAMS channels for surface

applications. Four of the MAMS visible and near-infrared channels are similar to the

first four channels of the Thematic Mapper (TM) on Landsat. Therefore, these

channels can be used in similar applications.

MAMS is somewhat unique compared to other airborne scanners, since it provides

some additional thermal infrared channels which have similarity to other satellite

sensors. The infrared channels from MAMS have commonality with those from the

Advanced High Resolution Radiometer (AVHRR) and VAS sensors on existing

weather satellites. The single thermal channel of the Landsat Thematic Mapper

covers a broader spectral range than the MAMS. Spectral response characteristics for

these common channels are presented in Table 2. The 11 /zm channels of MAMS and

VAS are very similar while that of the AVHRR is narrower and shifted toward
Z= 19.8

100 rn

0o \

\

\

\

I

I

I

I

I

H

I

I

I

\

\I

b

/ \

\ I

\ !

\!

N

Figure 1. MAMS scan geometry.

4
Table 1. Selected multispectral scanner channel characteristics

Visible Channels

Bandwidth (@50% repsonse)

Channel SPOT Landsat TM MAMS @ 5.0 mRa

1 0.45-0.52 0.42-0.45 "_

2 0.52-0.60 0.45-0.52

3 0.50-0.59 0.63-0.69 0.52-0.60

4 0.76-0.90 0.57-0.67

5 0.61-0.68 1.55-1.75 0.60-0.73

6 0.65-0.83

7 0.79-0.89 2.08-2.35 0.72-0.99

8 0.83-1.05

_Channel not available when 10-bit infrared data are collected.

5
°_

o_

rJ

n_

°_ _-_

0

_ii_

_0 o_ _O

I

_-_ _ _ _q

c_ c_ c_ c_

oo _ _-

_9

6
shorter wavelengths. The 12 _m channel of AVHRR is positioned near 11.8 _m

with a bandwidth about twice that of MAMS and VAS (which are centered at longer

wavelengths).

The standard MAMS instrument configuration (Table 3) uses the 5.0 mRa aperture

and 6.25 rps scan mirror speed. This configuration provides optimal sensing for very

high quality thermal measurements. Figure 1 shows the scan geometry for the

instrument when flown on the NASA high-altitude aircraft. The dimensions of the

ground resolution cell (nominally 100 m at nadir) increase with scan angle from nadir

by the sec2(0). The data are digitized at a fixed angular rate and, with the larger

aperture, result in about a 58% (58 m) overlaP from one instantaneous field-of-view

(ifov) to the next across the scan. The aircraft movement during a scan and from one

scan to the next produces an along-track overlap of 66% (66 m) for the FIFE

configuration (5.0 mRa aperture, 6.25 rps, 20-km nominal height, and 206 m/s air

speed). When the overlapping pixels are all displayed, a somewhat "blurred" scene is

available with 58 x 34 m resolution (at nadir). By sub-sampling the data during

post-processing, 100 x 100 m non-overlapping contiguous data are available.

Interpolation techniques are also used to restore the overlapping data to

quasi-independent 30-m resolution data.

MAMS FIFE Data

Two flights were made with MAMS over the FIFE region during Intensive Field

Campaign-1 (IFC-1). The first took place during the day of June 4 (1055 - 1154

LDT) and a second on the night of June 5, 1987 (2228-2350 LDT). These times

loosely correspond to a period of intense observations by other aircraft and

ground-based systems (Sellers et al., 1988). Aircraft restrictions, flight time, and

weather conditions limited data collection days and observation times. The flight

tracks for these flights are presented in Figure 2. For the June 4 flight, three

overpasses were made at roughly 21-min intervals. The passes were made in various

directions to measure different reflection patterns from particular regions. For the

night flight (June 5), five passes were made at two different angles and directions at

approximately 12-min intervals. The different flight directions also allowed for an

assessment of thermal emission on view geometry. Details on the MAMS flight

tracks and data coverage with respect to the FIFE study region are presented in the

Appendix.

The instrument configuration used for FIFE is shown in Tables 1 and 3. For the

FIFE flight of June 4, the visible channel gains were set so that saturation did not

occur over bright scenes. As a result the channel sensitivity approached that of the

quantization level which is a function of the channel calibration constant (or
Table 3. Standard MAMS instrument configuration

Scan speed

Instantaneous field-of-view (ifov)

Ground resolution @ 20 km

Total field-of-view (fov)

Swath width @ 20 km (agl)

Spectral bands

Roll correction

Pixels per scan line

Calibration sources

Digitization

6.25 rps

5.0 mRa

100 m at nadir

85.92 °

37.2 km

7 visible/near infrared"

3 thermal infrared b

+15.0 °

716

2 controlled blackbodies

8 bits (vis), I0 bit (IR)

_One visible channel is lost when 10-bit thermal data are collected

bA redundant fourth channel may be selected with a different gain setting
t----t

2O km

I i

k--

June 4, 1987

1055---1154 LDT

20

M

I

June 5, 1987

2228---2350 LDT

Figure 2. MAMS flight tracks over the FIFE study region.

9
instrument gain). These values are presented in Table 4. Random noise estimates

were made for the FIFE imagery based on structure function analysis (Hillger and

Vonder Haar, 1988). Extrapolation of the structure function curves to zero (or small)

separation distances allows an estimate of the random noise in a scene. This

technique has advantages over more traditional variance methods in that it is not

strongly biased by natural gradients in the scene. For the visible channels,

signal-to-noise values ranged from 20 to 70 for land scenes, with the highest values in

channel 7.

The 3.7 #m channel was used in place of the 6.5 t_m channel for FIFE. This

provided additional information on the surface thermal and emissivity characteristics.

The 3.7 _m channel was also selected as the redundant infrared channel available on

the Daedalus systems, and the gains were set such that better sensitivity was available

with channel 9 than with channel 10. A modification to the digitizer allowed for the

infrared channels to be collected with 10 bits of resolution with channel 1 (0.42-0.45)

becoming the "bit bucket" for the two least significant bits from the four infrared

channels (Jedlovec et al., 1989)i Ten-bit sensitivity Values for these channels are

shown in Table 4. All four:o_ihe :infrared channels werequite sensitive to small

temperature changes with sensitivity values less than 0' 1 K. The dynamic range

extended from 240-325 K for channels 9, 11, and 12 and up to 345 K for channel 10.

This range encompassed the observed brightness temperatures (not land surface

temperature) of the FIFE observations.

The accuracy of MAMS infrared data has improved since its development as

refinements to the instrument and calibration procedures were made (Jedlovec et al.,

1989). Thermal data from both FIFE flights are of very high quality. NEDT

estimates (determined from structure analysis) are equal to or less than the

quantization levels (Table 4). The relative accuracy of the temperature fields mapped

by MAMS has been shown to be very good. Thermal gradients in skin and

sea-surface temperature derived from MAMS data match precisely those derived from

AVHRR channel measurements and in situ observations (Jedlovec et al., 1989;

Moeller et al., 1989). Absolute accuracy is less certain and may range up to +4 K

depending on the type of data used in the comparison (Jedlovec et al., 1986a, 1989).

10
O0

O_

0

_D

_D

0

e_

e_

J_

_J

e_

Z

Z

Z

Z

t'_ _'_ "_ _ _ I_ _

,_ e- t_ "2.

11
CALIBRATION

Unlike low- and middle-altitude research aircraft, the high-altitude U2 does not

allow for direct interaction with any scientific instrumentation during a flight.

In-flight calibration data are not available for the visible channels. Therefore, raw

data in the visible channels are converted to radiance units based on pre- and

post-flight calibration data with a known light source. The visible channel calibration

values can change from one series of flights to another for a number of reasons. The

infrared calibration procedure used for the FIFE data is similar to that presented in

Jedlovec et al. (1989). The following two sections provide a detailed explanation of

the visible and infrared calibration procedures.

Visible Channels

Prior to each instrument flight, the gain for each visible channel is set to optimize

channel sensitivity and dynamic range for that flight. Gain values from previous

flights are used as initial input and are adjusted accordingly, to cover the expected

range of scene reflectances. The analog-to-digital processing of the MAMS data

during flight converts the dc restored channel voltages to 8-bit raw count values which

are recorded on magnetic tape. Visible channel data require post-processing to

convert raw counts into radiance values.

Since both scene and calibration data values are based on the performance of the

entire optical system, instrument component degradation (as a function of time) may

affect the measured radiance values. Probably most significant is the buildup of a

film (dirt) on the surface of the scan mirror. Since the scan mirror is exposed to the

environment throughout the flight, haze, atmospheric aerosols, and water vapor

contribute to the buildup of this film on the scan mirror. Because of the lack of

internal visible calibration on MAMS, the effect of this buildup is not known. The

resulting degradation of the signal is most significant at longer near infrared

wavelengths (Jeff Myers, NASA-Ames, personal communication). Therefore, in

order to obtain accurate visible channel data, periodic calibration with an integrating

sphere, and careful scan mirror cleaning is required. For the data collected during

the FIFE flights, calibration values from a May 1987 laboratory calibration were used

to convert raw counts to radiances. Post-deployment calibration using an integrating

sphere (July 1987) did not show any significant difference from pre-deployment

values.

Visible calibration values were determined in the laboratory with the MAMS

viewing a constant light source from an integrating sphere. The intensity of the light

12
from the sphereis accuratelyknown in 10-nmincrementsthroughoutthe visible and

nearinfraredportion of the spectrum. The integratingsphereitself was calibrated

againstBureauof Standardsprecisioninstrumentation.The relationshipof the

observedversusknown intensityvalueswasmodeledbasedupon thespectralresponse

characteristicsof the MAMS visible channels. The resultantcalibration values,X(0,

for the t= 2, 8th visible channel,were usedto convertflight datato radianceunits

using

-- C, w(Oz(OI C,(O (1)

where _vis(L) is the calibrated radiance, C_,(0 the raw count value, X(0 the

calibration value (from pre/post-flight calibration), and G(0 the gain in the t-th visible

channel. The channel gains and calibration values for the FIFE flights are presented

in Table 4.

Infrared Channels

The MAMS views a warm and a cold blackbody of known temperature every spin

(6.25 times per second). The blackbody temperatures are selected to encompass the

expected scene temperatures. Since the instrument response and infrared calibration

are highly linear in terms of radiances (Menzel et al., 1986), it is necessary to convert

known blackbody temperatures to channel radiances for application to the infrared

scene data. The upwelling radiance from the scene or blackbody, 9_i,, determined by

MAMS in a particular channel with a temperature, T,, is given by the convolution of

the channel spectral response _'0') and the Planck radiance, B, in the radiative transfer

equation as

IF I If I

,, P.

+[ I (1-_(u))rO')"(T(p),u)_kO')dr(p)dj' /

F 2

IFI

(2)

where 7"is the path atmospheric transmittance, _ is the surface emissivity, and _,

represents the wavenumber. The first term on the right-hand side represents the

upwelling radiation from the surface, the second term the downwelling radiation from

13
the atmospherereflectedto the instrumentby thesurface,and the third term is the

upwelling radiation from the atmosphere.Whenviewing the instrumentblackbodies

= 1, andthe atmosphereeffect betweenthe scanmirror and theblackbodiesis

negligible making r = 1, and dr = 0. Therefore, (2) becomes

F 1

i

=, ', (3)

F 1

_O')du

Pl

which still requires integration over the spectral response function. For easier

blackbody radiance determinations, (3) is approximated by

_, _/3 (T_,,po) (4)

where Uois the half power wavenumber defined by

Po m

I ff(v)dv

-- 0.50 (5)

This half power wavenumber best represents the asymmetric characteristics of the

spectral response curve. When vo is used in (4), the Planck function/3 approximates

the energy in a MAMS channel for a given temperature T. Since the Planck function

peak (maximum emission) shifts (with respect to wavelength or wavenumber) with

changing scene temperature, a correction to the half power wavenumber is necessary.

This monochromaticity correction is more conveniently applied to the temperature in

(4) than to the wavenumber and is calculated by forming linear relationships between

_'o and T over a typical range of scene temperatures. This application produces

corrections in each channel given by

T c = (T-oz2) / al (6) bb

14
sothat an improvedexpressionbecomes

_i_ = _ (T_ 'Vo) (7)

where a_ and or2 are linear regression coefficients. Values for the half power

wavenumbers and the temperature correction coefficients are listed in Table 1.

Equation (7) is only used in the calibration equations presented below; otherwise, the

more rigorous equation (2) is used.

Raw infrared count values from the scene were related to the energy received by

the detectors through an assumed linear response given by

_,_(L) = b(O + m (t) C(O (8)

where 9_ir(0 is the calculated radiance, C(t), the raw count value, and _ is the infrared

channel designator. The blackbody radiances Rbb(0, and the corresponding counts,

Cbb(t), form calibration curves for the MAMS channels. Calibration was performed

for each channel separately for every scan line. Values m(0 and b(0 are the slope

and intercept of the infrared channel calibration curves.

15
NAVIGATION

Navigation of flight data was performed for segments of flight tracks which are

straight lines. For these segments aircraft navigation parameters (latitude and

longitude) can be fit to linear functions with small residual errors. Navigation is used

for the selection of data segments, and the remapping of scenes to common ,nap

projections for Comparisons. Universal Transverse Mercator (UTM) and rectilinear

projections have been used for the MAMS FIFE data.

Data Sources

The aircraft inertial navigation system (INS) measured the aircraft position and

attitude. The parameters are recorded by the INS system every five seconds, or an

average of every 31.25 scan lines at 6.25 scans per second. The position parameters

were latitude, longitude, and altitude, while the attitude parameters were pitch, roll,

and heading. The aircraft roll does not affect the scene data since it is automatically

compensated for by the timing of the digital data recording in the instrument. The

INS latitude and longitude readings were used to plot the flight tracks on a map base,

with time tags at specified intervals (as in Figure 2 and in Figure A 1 of the

Appendix). Examination of these plots for various time intervals allowed the

selection of preliminary beginning and ending times for the extraction of scene data.

For straight line flight tracks the aircraft latitude and longitude are defined by

linear functions in time. Each parameter requires two coefficients: the initial value

(intercept) and the rate of change (slope). These are determined by linear regression

over the time period corresponding to the image. In the Man-computer Interactive

Data Access System (McIDAS) the coefficients are stored as ancillary data for each

image.

In some sections of the data tape, scan lines were not recoverable during the

transfer of data from the aircraft recorder tape to Computer Compatible Tape (CCT)

as a result of bit losses in the deconvolution system (Jeff Myers, NASA-Ames,

personal c0rnmunication). Gaps inthe_data must be filled in order to preserve the

geometry of the scene for navigation. During data extraction from the CCT, the

occurrence of a missing data line was detected by a gap in the scan line numbers

which are part of the documentation header for each line. If the expected scan line

number was not read, a fill line was generated. Fill lines were generated by using the

expected scan line number, the calibration information from the previous good line,

and linear interpolation of the data values between the surrounding two adjacent good

lines, which is tolerable because of the along track overlap from one line to the next.

16
For datalossesgreaterthanseverallines, a gapof zero values was left in the image.

Corresponding image and navigation segments are extracted by the time tags in

each data stream. For the data of June 4 the navigation error was greater than

expected from instrument drift, especially along the flight track. It was discovered

that the MAMS and INS clocks differed by slightly over 3 minutes. Since the aircraft

roll angle is recorded by both systems, the time difference can be determined by

matching roll variations. Plots of roll data from the first FIFE flight are given in

Figure 3 and show the time difference of approximately 3 minutes (0.05 hour). This

problem occurred temporarily because the MAMS clock was being set manually. An

interactive program was used to vary the time bias until the two plots matched.

The Algorithm

The Earth location of a MAMS pixel was found by first determining the elapsed

time from the beginning of the scene. The aircraft subpoint latitude and longitude

were determined from the linear fit equations. The scanner angle (DD) was obtained

from the data element location in the scan line and the angular distance per element

(Figure 1). The distance (D) from the aircraft subpoint to the data element was the

aircraft altitude multiplied by the tangent of the scanner angle. The direction of the

scan line is always at right angles to the current heading. The spherical triangle

formed by the scan line and the latitude lines through the pole was solved by the laws

of sines and cosines to determine the Earth coordinates of the image point.

An inverse navigation transform was used to determine image coordinates from

Earth coordinates. The algorithm was initialized with the input Earth location,

starting aircraft subpoint, and the direction of the flight track. Along with the scan

line through the input point perpendicular to the flight track, these parameters defined

a right triangle in the image (Figure 1). In this triangle, the distance along the track

and hence the elapsed time were obtained. The aircraft heading at this time was used

to rotate the scan line so that it is perpendicular to the heading. The aircraft nadir

point and elapsed time were adjusted accordingly. The scan rate and the elapsed time

were used to compute the number of scan lines to the input point. The distance along

the scan line was used to compute the element number.

Navigatiori Correction Using Landmarks

The correction technique for error and drift in the INS measurements evolved

using the eight FIFE overpasses. Once the navigation fit parameters have been

computed as a function of time, each point in the image can be Earth located. Earth

location values for landmarks identified in the scene were obtained to give a coarse

17
I

Q

I

...a

o

I

O

V--

i,-i1

1_.3 16,4 16 T

16.3

!

o

I

o

I

I

0

0

16.

!

IS.4 tS.S 15.6

I I I

time(c O

1E.7 15.B

t. I

IG.g

I

17.0

15.7 tr6.S 15.g 17.0

, , I L I

Figure 3. Aircraft ro]] data from INS and MAMS data streams.

18
estimate of the navigation accuracy. During the several hours of flight time, INS

navigation readings typically show an accumulated drift of a few kilometers, which

was apparent from a displacement in the location of landmarks in the imagery. The

FIFE scenes have an excellent central landmark which is the intersection of Interstate

70 and Kansas Highway 177. For the first pass, with a heading of due west, the

coordinates of the intersection were in error (i.e., translated) by 110 scan lines. The

calculated navigation coordinates at this position were corrected by solving two

equations for the corrections to the constant terms in the linear regression fits. The

images also showed rotations in some regions, due to the drift in the latitude and

longitude INS values during the elapsed time of a scene. This was reduced by

adjusting the slope coefficients of the regression fits and requires, at a minimum, a

second landmark in order to correct the second regression coefficient.

This method was found to be overly sensitive to the choice of the second

landmark, resulting in large adjustments to the slope coefficients, and navigation was

not improved at locations away from the landmarks. These results indicated that a

distribution of landmarks over the image was required. U. S. Geological Survey

(USGS) 7.5-minute (1:24,000 scale) topographic maps covering the FIFE site were

used to locate landmarks in Earth coordinates. The image locations were read from

magnified image displays centered on each of the landmark coordinates. For the

daytime images both visible and near infrared channels were used for identifying

landmarks, while only infrared images could be used at night. The latter had only

slight impact on registration accuracy. Thirty landmarks were located and the

adjustments were calculated by multiple linear regression. The adjustments to

intercepts and slopes are typically a few minutes of arc.

Although the latitude/longitude INS errors are small, the magnitudes of the

adjustments can be better understood relative to the MAMS resolution of 100 m,

which is approximately 0.001 °. For the first pass, with heading due west, the along

track (longitude) error at the 170-177 intersection is 0.0419 ° (or 2 minutes 31

seconds). In ground distance, at a latitude of 39.1 °, this error is 0.0419 ° X 111

km/deg X COS(39.1) = 3.6 km. This distance in scan lines, which are separated by

33 m, is 3.6/0.033 = 110 lines.

The INS parameter which has the largest impact is heading, sirce it typically has

variations of a few degrees, and one degree corresponds to 300 m at the extremes of

a scan line. Since a large number of landmarks and flight segments were available, a

study was undertaken to determine the correlation between INS measurements and

landmark errors. In the case of the FIFE data, the INS heading values were missing.

Therefore, heading values were derived from the aircraft velocity components, which

were available. These values will be referred to as the INS heading values. For each

19
landmark, theaircraft positionwas found from the elapsed time (based on scan lines)

and the regression fits. Then, the aircraft heading that would actually place the

landmark in the scanner's field of view was calculated. These headings were plotted

and compared to the INS values as shown for selected passes in Figure 4. The

variations in the two values are similar, although at times they are displaced,

indicating a bias in the INS readings. The correlation indicates the importance of

accurately representing the INS readings in the navigation calculations.

Consequently, two additions were made to the navigation process. The least

squares fits to altitude, heading, and pitch were expanded to include a quadratic term,

and their intercepts and slopes were corrected by applying multiple linear regression

to the landmark points. The headings determined from the corrected intercepts and

slopes and landmark-derived headings are shown in Figure 5. The root mean square

(RMS) errors in the landmark coordinates (pixels) are given in Table 5.

An additional requirement for obtaining the most accurate fits is the removal of

spurious and missing readings for aircraft pitch. Missing readings in the character

values are interpreted as zero. The occurrences of these spurious and missing points,

and the fits obtained when they are ignored, are shown in Figure 6.

Navigation Correction During Remapping

For both the day and night FIFE data, the overlapping images were remapped to a

UTM projection with 30-m spacing between pixels. Remapping to a new map

projection involves the moving of input pixels to their proper locations in the output

image. The remapping process requires stepping through the image coordinates of the

remapped output image, computing the Earth coordinates, and then computing the

corresponding image coordinates of the input image. The input pixel values are then

placed in the output image. This process requires two navigation transformations at

each coordinate, which is computationally time consuming. The MclDAS remapping

program uses a spline technique in which the navigation computations are performed

by default at 20-pixel intervals and linearly interpolated in between.

After remapping, navigation discrepancies were apparent as shifts between the

images. A plot of the displacements at 16-pixel intervals between the first two passes

over FIFE is shown in Figure 7. The largest displacements are around 6 pixels,

which can occur when the maximum navigation errors of three pixels are additive. A

technique was developed using a modified version of the Marshall Space Flight

Center (MSFC) automated winds routine (Wilson, 1984) to measure the residual shifts

and then remove them during the remapping. The residual errors in remapped images

were measured using template matching. Since the displacements between remapped

20
0

0

0 0

°

¢,4

I I I

16:01:49 10:02:29 16.'03:09 le:03:49

"riME

Figure 4.

¢} 0 _ o 0

• o 0

0

0

0 0

I I I

16:22:54 1823:34 10:24:14 18:24:54 1625:34.

TildE

Landmark-determined (points) and INS (line) headings.

21
i"

C'}

4:10:34

0 0 0 O: 0 0

0 _ 0 0 0

I I I

4:11:!4 4:11:64 4:1234

TIME

4:13:14

,,¢

Z

"Io,-

0

o

o

o

0 o o: o

o Oi_og

)</

L I L

4_-,-T]:33 4:28:13 4:28:53 4:29:33

TIME

4:30:13

Figure 4. (Continued)

22
16:01:49

0

o

0 0

o o_

I I I

16:02:29 16:03:09 16:03:49

"rIME

_:04:_

Figure 5.

tD

,,f

"1-

tO

0 0

0 0

O0 o 0

I I I

16"22:54 16".23:34 16".24:14 16".24:54.

TIME

16:25:34

Landmark-determined headings and corrected regression fit of headings.

23
O)

o

o _o 0

o

4:10:34

i I i

4:11:14 4:11:64 4:12:34

TIME

4:13:14

r,_

ID

up

o,-

o

o

o

o o

o

0

o o

i I I I

4:27:33 4,'.28:13 428:63 4".29:33 4:30:.13

TIME

Figure 5. (Continued)

24
Table 5. Landmark RMS errors (pixels)

Source of INS Values

Pass

1

2

3

4

5

6

7

8

INS

Alt/Pitch/Hdg

with

Interpolation

Linear Fit

Lat/Lon

Corrected

Lat/Lon,

Alt/Pitch/Hdg

Corrected

1.87

4.46

2.12

3.90

3.02

2.37

3.34

5.19

2.48

3.40

2.82

3.72

2.41

2.76

3.13

5.76

2.00

1.92

2.69

1.98

1.84

2.45

2.45

4.56

Quadratic Fit

Lat/Lon Lat/Lon,

Corrected AIt/Pitch/Hdg

Corrected

2.17 1.87

4.32 1.75

2.30 1.96

3.84 1.89

2.75 1.81

2.37 2.10

3.15 2.32

4.78 3.75

25
I -

16:01:49

O D

0 O 0

0 0

0

0

a 13 o o

r I +

16:02:29 18:03:09 16:03:49

TIME

10:04:_g

¢,N

+i- O.

0 a

O o

o o a

_i l I I

10:43:32 10:44:12 16:44:62 10:46:32

TIME

16:46:12

Figure 6. Regression fit of pitch with spurious readings ignored.

26
Figure 7. Displacements after remapping FIFE passes 1 and 2 into UTM

coordinates, where the length of the arrow indicates the displacement.

27
imagesare slowly varying spatially, largetemplatesof 75 pixels on a sidewere used.

The residualerrorsbetweenremappedimageswere measuredat 16-pixelintervals.

Displacementsneartheedgeswherethetemplatecannotbe movedwere obtainedby

usingimageslarger thanthe final remappedproducts. Someediting of incorrect

displacementswasdone. The displacementswere averagedso that the remapped

imageswere correctedto a commonlocation. In the remappingprogram, the

displacementswere removedfrom the outputimagecoordinatesbefore computingthe

input imagecoordinates. This processputs theinput pixelsat remappedpositions

without thedisplacements,and residualshifts areno longerapparent. The resulting

images from this procedure were co-registered to within one pixel over most of the

study region for both day and night data.

Universal Transverse Mercator (UTM) Grid System

The Universal Transverse Mercator projection and grid system has widespread

application, including the FIFE information System (FIS) (Sellers et al., 1988).

Beginning in 1977, many USGS maps have used this system, replacing the Polyconic

projection. Since it can be adapted for any region by defining a new axis, it is used

by many countries for topographic mapping and military maps, including the U.S.

Army since 1947. Maps of other planets and moons have also been generated in the

UTM coordinate system beginning in 1927.

The standard Mercator projection is defined geometrically by a cylinder wrapped

around the globe in contact with the equator. The Earth's features are projected onto

the cylinder, which is then cut at some point and laid out flat to form the map.

Longitude lines become parallel, rather than converging at the poles, and latitude lines

become spaced farther apart to compensate for the spread in longitude lines. Thus,

angles and local scales are preserved so that a constant azimuth line is straight. This

is the conformal property, and the line is called a loxodrome or rhumb line. Thus,

the Mercator projection is useful for navigation. The transverse Mercator projection

is generated by rotating the cylinder by 90 ° so that a longitude line becomes the

tangent or contact line, and a north-south strip is mapped very accurately. The

agreement between the cylinder and the globe can be increased by using a secant

cylinder, which is slightly less in diameter than the globe and so intersects it in two

places within the strip. The geometry of the projection is shown in Figure 8

(Greenhood, 1964).

Since the secant cylinder lies below the surface of the globe at the zone centers,

the scale is reduced by a factor of 0.9996 relative to the scale at the intersections of

the cylinder and the globe, which are 180 km from the zone centers. Scale variation

over a UTM zone is no more than 1 part in 1000 when an ellipsoid Earth model is

28
\

Figure 8. Transverse Mercator projection geometry (after Greenhood, 1964).

29
used. For U.S. mapsthe Clarke 1866ellipsoidis used. The UTM systemdivides

the world into 60 zonesof 6° width which arenumberedstartingat 180°

longitudeand increasingto the east. The U.S. zone numbers range from 10 on the

west coast to 19 on the east coast. The equator is assigned a value of 0 meters north,

and the central meridian is assigned a value of 500,000 meters east in order to avoid

negative numbers.

Projection Formulas

Formulas are used to transform from latitude and longitude values to UTM

coordinates in meters. Accuracy to within 1 meter can be obtained only by using a

realistic model for the Earth, which is very nearly an ellipsoid of revolution with a

flattening of about one part in three hundred. The Clarke 1866 ellipsoid has an

equatorial radius (a) of 6,378,206.4 meters and a polar radius of 6,356,583.8 m. The

flattening is then 1 / 294.98 and the eccentricity (e) is 0.082272. Distances on the

ellipsoid are typically calculated by integration of expressions in latitude and

longitude, which may require expansion in series before integration (Pearson, 1990).

The easting distance from the central meridian is, to first order, the product of the

scale (k, where k = 0.9996), the radius of curvature of the ellipsoid parallel to

latitudes (N), the longitude difference in radians, and a latitude cosine factor for the

reduced spacing of the meridian lines.

x = kN(_, - _,o)cos 4, (9)

= kNA

where,

A = (k - _o) cos 4,, with h and ho in radians.

The northing distance along a meridian on the ellipsoid is to the first order, the

•product of radius and latitude in radians, a4,. As a function of latitude and

eccentricity, integrated over the latitude range, the resulting series is

M = a [ ( 1 - e 2/4 - 3e 4/64 - 5e 6/256 -...)4, - (3e 2/8 ÷ 3e 4/32

+ 45e6/1024 + ... ) sin 2 4, + (15e4/256 + 45e6/1024 + ...) sin 44,

- (35e6/3072 + ...)sin 64, ÷...]

(10)

For the Clarke 1866 eccentricity constant, the series can be evaluated as:

30
M -- 6,367,399.6905 r - 16216.94sin205 + 17.21sin405 - 0.02sin605 (11)

The expressions corrected for higher order terms in latitude and longitude are as

follows:

x = kN[A + (1 - T + C)A 3/6 + (5 - 1ST+ T 2 + 72C- 58e / 2)n5/120]

y = k{M+N tan05 [A 2/2 +(5 - T+9C+4C2)A4/24

+ (61 - 58T+ T _ + 600C - 330e'2)A 6/720]}

(12)

where,

e '2 = eV(1 - e _)

N = a/(1 - e_ sin s 05)'a

T = tan2 05

C = e 12cos 2 05

For the inverse equations, the latitude is, to first order, called the rectifying

latitude (t_), and is 90 degrees times the ratio of the distances from the equator to the

input point (M) and to the Pole. The distance (M) along a meridian is given above as

a series in eccentricity and actual latitude, and after evaluation with Clarke constants.

Inverting the equation for t_, as a function of 05, gives the latitude at the central

meridian in terms of eccentricity and ix:

051 = # + (3e_/2 - 27e_3/32 +...) sin 2/z + (2 le,2/16 - 55e_4/32 +...)sin 4#

+ (15 le,3/96 -...) sin 6_ + (1097e_4/512 -...) sin 8# +...

= /_+ 2.5468693 X 10-3 sin 2# + 3.7839708 X 10-6 sin 4/z

(13)

The latitude away from the central meridian is corrected by a series of terms

which are second order and above in the easting value:

05 = 05_-(N, tan05_/Rt)[D2/2-(5 +3T_ + 10C i -4C_ 2 -9e/2)D4/24

+ (61 +90T t +298C 1+45TI 2 -252e z2 _ 3C2)D6/720]

(14)

31
where

e'2 = e2/(1 - e2)

Ct =e '2cos2_

Tt = tan 2 4h

Nt = a/(1 - e2 sin 2 qSl)'_

Rl = a(l - e2)/(1 - e2 sin 2 (b_)3/2

D = x/(Nlk)

N_ is the radius of curvature of the ellipsoid perpendicular to a meridian, and

Rt is the radius of curvature along a meridian.

The longitude from the central meridian is, to first order, the angle

subtended by the easting distance (x):

x D

X - Xo - = (15)

kN_cos4,, cos6_

Correction terms are third order and above in D:

)_ = _,o.[D-(I+2Tt÷C,)D3/6* (5-2C_÷ 28T_

-3Ct 2 . 8d 2 ÷24T12)DS/120]/cosrbl

(16)

These transformations were coded and tested using a numerical example from

Snyder (1987). In the example below, the latitude to be transformed is 40.5 ° and the

longitude is 73.5 ° . Numerical values were examined to determine the necessity of

higher degree correction terms in order to obtain accuracy on the order of one meter,

since the series expansions above provide fractional meter accuracy.

For the forward transformation, the UTM distances are the arc lengths subtended

by the latitude and longitude angles. Since the central meridian of UTM zone 18 is

75 °, the longitude subtended angle is 1.5 °. Some of the relevant values follow.

Radius of curvature along longitude at 40.5 deg (N)

Initial easting - scale x radius x angle subtended

Third degree in latitude correction

Fifth degree in latitude correction

Final calculated easting distance

Correct easting distance

6,387,330.5

127,104.1

2.304

-0.00128

127,106.4

127,106.5

32
Distancealongcentralmeridianto latitude40.5 (M)

Iniiial northing = scalex M

Seconddegreein latitudecorrection

Fourth degreein latitudecorrection

Final calculatednorthingdistance

Correct northingdistance

4,484,838.0

4,483,044.0

1,080.98

0.154

4,484,124.7

4,484,124.4

The correctionsdo not addto thetotal exactlydue to computerroundoff.

For theinversetransformation,the latitudeandlongitudeanglesare subtendedby

the UTM arc lengths.

Initial latitudebasedon sphericalEarth

Latitudeusingellipsoidalradius

Latitude at centralmeridian(4,_)(calledfootpointlatitude)

Radiusof curvaturealonglongitudeat latitude4_t (Nt)

Radius of curvature along latitude at latitude 4_1 fRO

Second degree in easting correction

Final calculated latitude

40.2972

40.3656

40.5097

6,387,334.0

6,362,271.4

0.0097

40.5O0

Initial longitude difference at latitude 4_1

Third degree in easting correction

Final calculated longitude distance

1.5002

0.0002

1.5000

33
IriS DATASET

The data sent to FIS were remapped into a UTM projection covering the FIFE

study area. The region covered by these data is presented in Table 6. The image

size is 512 x 512, with a pixel spacing of 30 m. Units for IR channels are brightness

temperature (K) x 100 and the visible channels are in Wm 2 #m -_ ster _ X 100. The

latitude/longitude files are in degrees x 100. The flight legs, times, and channels

available are shown in Table 7. The MAMS FIS dataset is available by contacting:

Dr. D. E. Strebel

NASA/Goddard Space Flight Center

Code 923

Greenbelt, MD 20771

Data Quality

The dataset created for FIS is of very good quality. However, as with most

datasets there are a few problems. The data in band 8 for all of the daytime passes

has a "grainy" appearance due to a stuck bit which induced erroneous eight count

variations in the raw data. Thus, the radiance values derived from this data reflect

this variability. On the second daytime and the fourth nighttime passes there are

regions of missing data in the northeast corner. In these regions the brightness

temperature values were set to 0. Due to reflected solar radiation in the 3.7 _m band

(channel 10) a few values exceed 328 K. Since the data have been scaled by 100 and

the maximum value which can be stored in a 2-byte integer form is 32767, data

values that exceed 327.67 K have been set to 32767. Finally, the raw data in

channel 10 contained some "speckling" of bad raw values, which is manifested in the

derived brightness temperatures. The cause of this problem is unknown.

34
Table6. FIS Datacoverageregion

Corner

Earth Coordinates

Latitude Longitude

Northwest 39:07:05 96:36:48

Northeast 39:06:51 96:26:10

Southeast 38:58:34 96:26:28

Southwest 38:58:48 96:37:04

UTM Coordinates

Northing Easting

4,332,380 706,350

4,332,380 721,680

4,332,380 721,680

4,317,050 706,350

35
Table 7. MAMS FIS Datafor eachpass

Flight Leg

Time

Channels

Day LDT UTC

1 4 June 1987 11:01:49 16:01:49 2-8, 10-12 :'

11:04:29 16:04:29

2 4 June 1987 11:22:54 16:22:54 2-8, 10-12 _

11:25:33 16:25:33

3 4 June 1987 11:43:32 16:43:32 2-8, 10-12 _

11:46:12 16:46:12

4 5/6 June 1987 22:35:09 03:35:09 10-12 _

22:37:49 03:37:49

5 5/6 June 1987 22:47:46 03:47:46 10-12:'

22:50:26 03:50:26

6 5/6 June 1987 22:58:52 03:58:52 10-12:'

23:01:31 04:01:31

7 5/6 June 1987 23:10:34 04:10:34 10-12 _'

23:13:13 04:13:13

8 5/6 June 1987 23:27:33 04:27:33 10-12"

23:30:13 04:30:13

:%lthough channel 9 is more sensitive than its redundant channel 10, spurious noise in

channel 9 limited its usefulness.

36
JOURNAL OF GEOPHYSICAL RESEARCH (JGR) DATASET

MAMS data collected during the two flight days described above were used to

support an investigation of the thermal variability of surface features over the FIFE

region. This research is described in the JGR special issue on FIFE (November

1992). The data used are very similar to that submitted to the FIS and described in

this report. Several differences exist between the data sets:

(1) only two day-time passes and two night-time passes were used,

(2) the data were navigated and co-registered based on only those times and

not all times as in the FIS data set, and

(3) the data were remapped into a rectilinear coordinate system with 50-m

resolution.

The data used in the FIFE JGR paper covered a 19 x 21 km area which was

slightly larger than but centered on the FIFE study site and virtually identical to the

domain of the FIS data set. For both the day and night flights only the first and last

passes over the region were used (see Table 7 for times).

For the JGR dataset, MAMS data and derived products were remapped into a

rectilinear coordinate system corresponding to the data region (FIFE study site). The

resulting images contained 420 lines and 380 elements of data. For both days, the

first of the two images in the time sequence was navigated and Earth located to within

several pixels of ground control points described above. The second image was then

registered to the first image using the procedures described in this report. This

provided preliminary image co-registration. A 50-meter spacing between image

points was produced by the remapping procedure using the overlapping pixel

information. This provided finer detail in the derived products compared with

undersampling the raw data to produce 100-m resolution.

Residual shifts in the navigation were measured at pixel spacings of 20 and fed into

the remapping program to be used as a bias in the computation of the image

coordinates. The resulting images from this procedure were co-registered to within

one pixel over most of the study region for both day and night data.

37
SUMMARY

Airborne multispectral imagery from the Multispectral Atmospheric Mapping

Sensor (MAMS) were collected over the First ISLSCP Field Experiment (FIFE) on

two days during Intensive Field Campaign - 1 (IFC-1) to study the time and space

variability of remotely-sensed geophysical parameters. MAMS data were collected

for three daytime passes on June 4 and five nighttime passes on June .5, 1987 over the

site. The high spatial resolution of the sensor and low single sample noise in the

visible and infrared channels allowed for an indepth analysis of the spatial variability

of several derived geophysical parameters (Jedlovec and Atkinson, 1992). The

radiance data and derived products were remapped and rectified to common

coordinates so that multi-scene analysis of the data was possible. The multi-temporal

nature of the data set provided valuable insight to the use of time change parameters

from remote sensing platforms.

38
REFERENCES

Greenhood, D., 1964: Mapping. University of Chicago Press, 289 pp.

Hillger, D. W., and T. H. Vonder Haar, 1988: Estimating noise levels of remotely

sensed measurements from satellites using spatial structure analysis. J. Atmos.

Ocean. Tech., 5, 206-214.

Jedlovec, G. J., 1987: Determination of atmospheric moisture structure from high

resolution MAMS radiance data. Ph.D. Thesis, The University of

Wisconsin-Madison, 173 pp. [available University Microfilms International, 300

North Zeeb Road, Ann Arbor, MI 48106-1346].

, 1990: Precipitable water estimation from high resolution split window

radiance measurements. J. Appl. Meteor., 29, 863-877.

, and R. J. Atkinson, 1992: Variability of geophysical parameters from

aircraft radiance measurements for FIFE. J. Geophys. Res., 97, 18,913-18,924.

, K. B. Batson, R. J. Atkinson, C. C. Moeller, W. P. Menzel, and M. W.

James, 1989: Improved Capabilities of the Multispectral Atmospheric Mapping

Sensor (MAMS). NASA TM-100352, 80 pp. [available NTIS N89-20430].

, W. P. Menzel, R. Atkinson, G. S. Wilson, and J. Arveson, 1986a:

The Multispectral Atmospheric Mapping Sensor (MAMS): Instrument Description,

Calibration, and Data Quality. NASA TM-86565, 37 pp. [available NTIS].

, W. P. Menzel, G. S. Wilson, and R. J. Atkinson, 1986b: Detection of

mountain induced mesoscale wave structures with high resolution moisture

imagery. Second Confi, rence on Satellite Meteoroh)gylRemote Sensing and

Applications, AMS, Williamsburg, VA, pp. 365-369.

Menzel, W. P., G. J. Jedlovec, and G. S. Wilson, 1986: Verification of small scale

features in VAS imagery using high resolution MAMS imagery. Second

Con_,rence on Satellite Meteoroh_gy/Remote Sensing and Applications, AMS,

Williamsburg, VA, pp. 108-11 I.

Moeller, C. C., L. E. Gumley, K. I. Strabala, and W. P. Menzel, 1989: High

resolution depiction of SST and SSC from MAMS data. Foltrt]_ Co#!f. o#! Satellite

Meteoroh_gy and Oceanography, AMS, San Diego, CA, pp. 208-212.

39
, W. P. Menzel, andK. I. Strabala,1990:High resolutionatmosphericand

surfacevariability from combinedMAMS andVAS radiances.OSA Topical

Meeting on Optical Remote Sensing of the Atmosphere, Optical Society of America,

Reno, Nevada.

Pearson, F., 1990: Map projections: Theory and applications. CRC Press, 372 pp.

Sellers, P. J., and F. G. Hall, 1987: First ISLSCP Field Experiment (FIFE):

Experiment Plan, 177 pp. [available from NASA/Goddard Space Flight Center,

Code 923, Greenbelt, MD 20771].

Sellers, P. J., F. G. Hall, G. Asrar, D. E. Strebel, and R. E. Murphy, 1988: The

First ISLSCP Field Experiment (FIFE). Bull. Amer. Meteor. Soc., ti9, 22-27.

Snyder, John P., 1987: Map projections--A working manual. U. S. Geological

Survey Professional Paper 1395, 383 pp.

Wilson, G. S., 1984: Automated mesoscale wind fields derived from GOES satellite

imagery. Conf. Satellite Remote Sensing and Applications, AMS, Clearwater

Beach, FL, pp. 164-171.

40
APPENDIX

Raw data values (in units of radiance) are shown for each pass in Figure A 1. The

aircraft flight tracks are plotted as straight lines after correction using the landmarks.

UTC times are indicated at each directional arrow. The images are rotated so that the

flight tracks are in the proper direction with respect to the Earth. The FIFE study

region is outlined. The distortions in this square region are due to differing pixel

overlaps in the along track and scan directions, and the increase in ground coverage

with scan angle, which compresses the image noticeably at large scan angles. The

missing data values at the edges of the last two passes are due to aircraft roll.

41
16: 02

Figure A 1. MAMS raw imagery with the flight track information and the FIFE

study region (outlined) for each of the passes shown in Table 7.

42
IG" 2G

Figure A1. (continued)

43
Figure A1. (continued)

44
321

Figure A1. (continued)

45
j •

03:"1"7

Figure A1. (continued)

46
03:59

Figure AI. (continued)

47
=

!

|

Figure A1. (continued)

48
Figure A1. (continued)

49
APPROVAL

CALIBRATION, NAVIGATION, AND REGISTRATION OF

MAMS DATA FOR FIFE

By

G. J. Jedlovec and R. J. Atkinson

The information in this report has been reviewed for technical content. Review of

any information concerning Department of Defense or nuclear energy activities or

programs has been made the MSFC Security Classification Officer. This report, in its

entirety, has been determined to be unclassified.

SpeaP_U_s]c,ence Laboratory

U. S. GOVERNMENT PRINTING OFFICE 1993 733--050 / 80039