NASA/TMm2000-209891, Vol. 42

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 42

BOREAS RSS-1 PARABOLA SSA

Surface Reflectance and Transmittance

Data

DonaM D. Deering, Goddard Space Flight Center, Greenbelt, Maryland

Thomas F. Eck and Babu Banerjee, Raytheon ITSS

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

July 2000

https://ntrs.nasa.gov/search.jsp?R=20010021920 2018-05-14T15:18:45+00:00Z
TheNASA STIProgramOffice ... in Profile

Sinceits founding,NASAhasbeendedicatedto

theadvancement of aeronauticsandspace

science.TheNASA ScientificandTechnical

Information(STI)ProgramOfficeplaysakey

partinhelpingNASAmaintainthisimportant

role.

TheNASASTIProgramOfficeis operatedby

LangleyResearchCenter,theleadcenterfor

NASA'sscientificandtechnicalinformation.The

NASASTIProgramOfficeprovidesaccessto

theNASASTIDatabase, thelargestcollectionof

aeronauticalandspacescienceSTIin theworld.

TheProgramOfficeis alsoNASA'sinstitutional

mechanismfor disseminatingtheresultsof its

researchanddevelopmentactivities.These

resultsarepublishedbyNASAintheNASASTI

ReportSeries,whichincludesthefollowing

reporttypes:

• TECHNICALPUBLICATION.Reportsof

completedresearchor amajorsignificant

phaseofresearchthatpresentheresultsof

NASAprogramsandincludeextensivedataor

theoreticalanalysis.Includescompilationsof

significantscientificandtechnicaldataand

informationdeemedto beof continuing

referencevalue.NASA'scounterpartof

peer-reviewedformalprofessionalpapersbut

haslessstringentlimitationsonmanuscript

lengthandextentof graphicpresentations.

• TECHNICALMEMORANDUM.Scientific

andtechnicalfindingsthatarepreliminaryor

of specializedinterest,e.g.,quickrelease

reports,workingpapers,andbibliographies

thatcontainminimalannotation.Doesnot

containextensiveanalysis.

• CONTRACTORREPORT.Scientificand

technicalfindingsby NASA-sponsored

contractorsandgrantees.

CONFERENCEPUBLICATION.Collected

papersfromscientificandtechnical

conferences,symposia,seminars,or other

meetingssponsoredor cosponsoredby NASA.

SPECIALPUBLICATION.Scientific,technical,orhistoricalinformationfromNASA

programs,projects,andmission,oftenconcernedwith subjectshavingsubstantialpublic

interest.

TECHNICALTRANSLATION.

English-languagetranslationsof foreignscientific andtechnicalmaterialpertinentto NASA's

mission.

SpecializedservicesthatcomplementtheSTI

ProgramOffice'sdiverseofferingsincludecreating customthesauri,buildingcustomizeddatabases,organizingandpublishingresearchresults...

evenprovidingvideos.

FormoreinformationabouttheNASASTIPrograinOffice,seethefollowing:

AccesstheNASA STIProgramHomePageat

http://www,sti.nasa.gov/STI-homepage.html

E-mailyourquestionviatheInternetto

help@sti.nasa.gov

Faxyourquestionto theNASAAccessHelp

Deskat(301)621-0134

• TelephonetheNASAAccessHelpDeskat

(301)621-0390

Write to:

NASAAccessHelpDesk

NASACenterfor AeroSpaceInformation

7121StandardDrive

Hanover,MD 21076-1320
NASA/TMm2000-209891, Vol. 42

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 42

BOREAS RSS-1 PARABOLA SSA

Surface Reflectance and Transmittance

Data

DonaM D. Deering, Goddard Space Flight Center, Greenbelt, Maryland

Thomas F. Eck and Babu Banerjee, Raytheon ITSS

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

July 2000
NASACenterforAeroSpaceInformation

7121StandardDrive

Hanover,MD21076-1320

PriceCode:A17

Availablefrom:

NationalTechnicalInformationService

5285PortRoyalRoad

Springfield,VA22161

PriceCode:A10
BOREAS RSS-1 PARABOLA SSA Surface Reflectance and Transmittance

Data

Donald W. Deering, Thomas F. Eck, Babu Banerjee

Summary

The BOREAS RSS-1 team collected surface reflectance and transmittance data from three forested sites

in the SSA. This data set contains averaged reflectance factors and transmitted radiances measured by

the PARABOLA instrument at selected sites in the BOREAS SSA at different view angles and at three

wavelength bands throughout the day. PARABOLA measurements were made during each of the three

BOREAS IFCs during the growing season of 1994 at three SSA tower flux sites as well as during the

FFC-T. Additional measurements were made in early and mid-1996 during the FFC-W and during

IFC-2. The data are stored in tabular ASCII files.

Note that data other than those described here were collected by the RSS-01 team but were either not

provided to or integrated into BORIS. However, these additional data are available from the ORNL

DAAC (see Sections 15 and 16).

Table of Contents

1) Data Set Overview

2) Investigator(s)

3) Theory of Measurements

4) Equipment

5) Data Acquisition Methods

6) Observations

7) Data Description

8) Data Organization

9) Data Manipulations

10) Errors

11) Notes

12) Application of the Data Set

13) Future Modifications and Plans

14) Software

15) Data Access

16) Output Products and Availability

17) References

18) Glossary of Terms

19) List of Acronyms

20) Document Information

1. Data Set Overview

1.1 Data Set Identification

BOREAS RSS-01 PARABOLA SSA Surface Reflectance and Transmittance Data

1.2 Data Set Introduction

The Portable Apparatus for Rapid Acquisitions of Bidirectional Observations of Land and

Atmosphere (PARABOLA) is an instrument specifically designed to measure variations in reflectance of

forest canopies as a function of solar and sensor viewing geometry, wavelength, and canopy

biophysical characteristics. These data are averaged reflectance factors and transmitted radiance values of

selected sites in the BOReal Ecosystem-Atmosphere Study (BOREAS) Southern Study Area (SSA) at

Page 1
differentview angleswithinthreewavelengthregionsthroughoutheday.Therawdatafor eachchannel

duringeachacquisitionwerebinnedbycreating144conicalbinswithin thesphericalspacethat

surroundstheinstrument;thedatapointsthatfell within eachbin werethenaveraged.

1.3 Objective/Purpose

This study had the following objectives:

• Characterize the multidirectional interactions of solar energy in various types of boreal forest

canopies through intensive measurements and modeling.

• Relate these characteristics to ecologically important biophysical parameters.

• Provide bidirectional reflectance measurements of the various boreal forest canopies.

• Determine the variability of reflected and emitted radiation in selected spectral wavebands as a

function of canopy type, phenological growth stage, and solar zenith angle (SZA).

• Estimate surface albedo and Photosynthetically Active Radiation (PAR) albedo from

bidirectional reflectance and irradiance data.

The PARABOLA allowed for rapid acquisition of bidirectional observations of the land and atmosphere,

by measurement of the angular distributions of reflected and transmitted radiation of natural Earth

surface targets. Its specific purpose was to provide bidirectional reflectance measurements of the various

boreal forest canopy types.

1.4 Summary of Parameters

Radiance, reflectance, and illumination and viewing angles.

1.5 Discussion

PARABOLA is an instrument specifically designed to measure variations in vegetation reflectance as

a function of solar and sensor viewing geometry, wavelength, and plant canopy biophysical

characteristics. The data are averaged reflectance factors and transmitted radiances of selected sites in the

BOREAS SSA at different view angles and in three wavelength regions throughout the day. The raw

data for each channel and time period were binned by creating 144 conical bins within the spherical

space that surrounds the instrument. The measured data points that fell within each bin were then

averaged. PARABOLA measurements were made during the Focused Field Campaign-Thaw (FFC-T)

as well as during each of the three BOREAS Intensive Field Campaigns (IFCs) in 1994 at three tower

sites within the BOREAS SSA. Measurements also were made during the Focused Field

Campaign-Winter (FFC-W) and during IFC-2 in 1996.

1.6 Related Data Sets

BOREAS RSS-02 Level-lb ASAS Imagery: At-sensor Radiance in BSQ Format

BOREAS RSS-03

BOREAS RSS-03

BOREAS RSS-11

BOREAS RSS- 12

BOREAS RSS-18

BOREAS RSS- 19

BOREAS RSS- 19

BOREAS RSS-20

Reflectance Measured from a Helicopter-Mounted Barnes MMR

Reflectance Measured from a Helicopter-Mounted SE-590

Ground Network of Sunphotometer Measurements

Automated Ground Sunphotometer Measurements in the SSA

Level-1B AVIRIS Imagery: At-sensor Radiance in BIL Format

1994 CASI At-sensor Radiance and Reflectance Images

1996 CASI At-sensor Radiance and Reflectance Images

POLDER C-130 Measurements of Surface BRDF

Page 2
2. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. Donald W. Deering, Principal Investigator

Dr. Elizabeth M. Middleton, Co-Investigator

Dr. Suraiya P. Ahmad, Co-Investigator

Mr. Thomas F. Eck, Co-Investigator

2.2 Title of Investigation

Radiative Transfer Characteristics of Boreal Forest Canopies and Algorithms for Energy Balance

and PAR Absorption

2.3 Contact Information

Contact 1:

Dr. Donald W. Deering

Code 923

NASA GSFC

Greenbelt, MD 20771

(301) 614-6671

(301) 614-6695 (fax)

Donald.Deering@ gsfc.nasa.gov

Contact 2:

Thomas F. Eck

Raytheon ITSS

NASA GSFC

Code 923

Greenbelt, MD 20771

(301) 614-6625

(301) 614-6695 (fax)

Thomas.Eck@ gsfc.nasa.gov

Contact 3:

Jaime Nickeson

Raytheon ITSS

NASA GSFC

Code 923

Greenbelt, MD 20771

(301) 286-3373

(301) 286-0239 (fax)

Jaime.Nickeson@ gsfc.nasa.gov

3. Theory of Measurements

The focus of this research was to characterize the variation in vegetation reflectance as a function of solar

and sensor viewing geometry, wavelength, and plant canopy biophysical characteristics. An

understanding of these relationships is necessary for meaningful biophysical and ecological

interpretations of measurements acquired from airborne and satellite sensors. PARABOLA can measure

these variations in reflectance because it measures at different viewing angles and at three spectral bands.

Light radiation striking a vegetative canopy interacts with individual phytoelements (leaves, stems,

branches) and the underlying substrate. The interaction depends on light quality, radiative form (direct

Page 3
ordiffuse),illuminationincidenceangle,vegetativecomponentopticalproperties,andcanopy

architecture.Radiationisreflected,transmitted,or absorbed.Researchershaveshownthat

phytoelementsandsubstratesarenotperfectLambertianreflectors;i.e.,theydonotreflectequallyin all

directions(Walter-Shea,et al., 1989;Ironset al., 1989).Theamountof leafareaandtheleafangle

distributionwill determinetheamountof vegetationandsubstratethatis sunlitandshaded.Theamount

of vegetationandsubstrateandrespectiveamountsof sunlitandshadedcomponentsin a scenewill vary

dependingontheangleatwhichit is viewed;i.e.,thecanopyisitself anon-Lambertiansurface.Thus,

canopyilluminationandviewinggeometryarecriticalin determiningtheamountof reflectedradiation

receivedat thesensor.

Reflectedradiationmeasurementswereconvertedtoradianceandreflectancefactors(theratioof

reflectedradianceto incidentradiance).Thereflectancefactoris theratioof thetargetreflectedradiant

flux to anidealradiantflux reflectedby anidealLambertianstandardsurfaceirradiatedin exactlythe

samewayasthetarget.Reflectedradiationfrom afield referencepanelcorrectedfor nonperfect

reflectanceandSunanglewasusedasanestimateof theidealLambertianstandardsurface(Walter-Shea

andBiehl, 1990).

4. Equipment

4.1 Sensor/Instrument Description

The basic PARABOLA instrument is a three-channel, rotating-head radiometer consisting of three

primary units: the sensor head, the data recording unit, and the internal power pack. The sensor head is

composed of a motor-driven tow-axis gimbal on which three detector units are jointly mounted. The

three detectors include two silicon and one germanium solid-state detectors, with filters configured to

correspond to Thematic Mapper (TM) spectral bands 3, 4, and 5 (630-690, 760-900, and 1550-1750

nm), respectively. They are temperature-regulated (by cooling or heating) through thermoelectric

proportional control circuits. Also, because of the tremendous range in target brightness that can be

expected in scanning a two-hemisphere field of view (FOV), an auto-ranging amplifier is used to switch

the gain levels back and forth by factors of 1, 10, and 100 to maintain maximum radiometric sensitivity.

The detector cones confine the FOV to 15 degrees. The two-axis, two-motor rotation of the head enables

a near-complete sampling of the entire sky/ground sphere. There is a 15 degree exclusion area toward

the mounting device because of mechanical limitations.

4.1.1 Collection Environment

The PARABOLA instrument was mounted on a tram that traversed a fixed set of tram cables at each

of the three BOREAS tower/tram sites in the SSA (Old Aspen (OA), Old Jack Pine (OJP), and Old

Black Spruce (OBS)). The tram cabling height was approximately 13-14 meters above the height of the

forest canopy at each site. PARABOLA measurements were made on days of 0 to 30% cloud cover,

beginning at about 75 degrees SZA to solar noon.

4.1.2 Source/Platform

PARABOLA's two-axis motorized radiometer and leveling head, with a camera-mounting

attachment, were mounted on a tram that traversed a fixed set of tram cables at each of the three

BOREAS tower/tram sites in the SSA OA, OJP, and OBS. The tram cabling height was approximately

13-14 meters above the height of the forest canopy at each site. PARABOLA data measurement scans

were made at distances from the principal scaffold flux tower ranging from 25 meters to 5 meters at

2-meter increments. This resulted in PARABOLA scans being taken at 11 subsites along the tram

transect for each SZA set. All operations of PARABOLA and the adjacent canopy wide-angle camera

were controlled from PARABOLA's data system control panel on the flux tower. PARABOLA

measurements were also taken on under-canopy trams at 4 meters above ground level with the same

sampling interval as the above-canopy measurements for both the OA and the OJP data sets. For the

OBS site, under-canopy measurements were taken with the instrument mounted on a large tripod that

was lifted and moved manually for spatial sampling.

Page 4
4.1.3 Source/Platform Mission Objectives

The purpose of the installed towers and tram wires was to provide a place on which the

PARABOLA could rest and obtain measurements.

4.1.4 Key Variables

Radiances, reflectance, and viewing angle.

4.1.5 Principles of Operation

The scan system is designed such that sampling is done in a continuous helical pattern. The data are

recorded serially in digital form. There is also a "calibrate"/hold position (mode) that allows manual

pointing of the detector head for individual measurements of calibration sources in any direction. In the

helical sampling mode, a complete data set can be taken in 11 seconds followed by a data dump to a

portable PC from the buffer.

4.1.6 Sensor/Instrument Measurement Geometry

PARABOLA's design provides multidirectional viewing, but the system's geometry does not allow

the same "spot" on the ground to be measured at each view direction. Thus, target surfaces that are

homogeneous over relatively large areas are sampled with replication. Routinely, 11 subsites were

sampled along each BOREAS tram transect to minimize any within-field heterogeneity effects and to

improve the sensitivity to angular reflectance features of the surfaces. The 15-degree internal field of

view (FOV) of the sensor provides "viewing areas" that are similar in scale relative to the spatial

structure of the surfaces measured. The various pixels range from approximately 5.4 square meters at

nadir to approximately 46.6 square meters at an off nadir angle of 60 degrees.

4.1.7 Manufacturer of Instrument

National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC)

Biospheric Sciences Branch Greenbelt, MD 20771

4.2 Calibration

Radiometric laboratory calibration of PARABOLA was performed at NASA GSFC on a 1.8-m

spherical integrator using 12 200-W quartz halogen lamps (2950 K at 6.5 A). The number of lamps

illuminating the sphere is varied to produce 12 radiance levels for calibration. No field calibration was

performed.

4.2.1 Specifications

Laboratory Calibration:

Three separate calibration runs are made to fully calibrate PARABOLA at a wide range of radiance

levels. Neutral density filters (0.1 density level) are used for the lowest gain setting. The voltage

response to radiance level relationship is linear in all three spectral channels for each gain setting with

correlation coefficients of 0.999.

4.2.1.1 Tolerance

None given.

4.2.2 Frequency of Calibration

Laboratory Calibration:

The last PARABOLA calibration was done on 02-Oct-1996. The PARABOLA instrument is calibrated

using the GSFC 1.8-m integrating sphere (located in Bldg. 22) as the standard radiance source. The

PARABOLA instrument was calibrated against the 1.8-m sphere before the FFC-T on 28-Mar-1994,

between IFC-1 and -2 on 24-Jun-1994, and after IFC-3 on 04-Oct-1994. Measurements are made with

and without a nominal 10% neutral density filter for the 12 lamp levels of the 1.8-m sphere.

Page 5
4.2.3 Other Calibration Information

None.

5. Data Acquisition Methods

Data were acquired from the PARABOLA instrument mounted on a tram system that traversed a fixed

set of cables at each of the three BOREAS tower/tram sites in the SSA OA, OJP, and OBS. The tram

cabling height was approximately 13-14 meters above the height of the forest canopy at each site.

PARABOLA data measurement scans were made at distances from the principal scaffold flux tower

ranging from 5 meters to 25 meters at 2-meter increments. This resulted in PARABOLA scans being

taken at 11 subsites along the tram transect for each SZA set. All operations of PARABOLA and the

adjacent canopy wide-angle camera were controlled from the PARABOLA data system control panel on

the flux tower. PARABOLA measurements were also taken on under-canopy trams at 4 meters above

ground level with the same sampling interval as the above-canopy measurements for both the OA and

the OJP data sets. For the OBS site, under-canopy measurements were taken with the instrument

mounted on a large tripod that was lifted and moved manually for spatial sampling (see Section 9.2 for

details).

6. Observations

6.1 Data Notes

The SZA views that were provided with the data represented a solar angle at the end time of the data

acquisition period. Solar azimuth angles were not provided in the original data files. BOREAS

Information System (BORIS) staff" calculated both the solar azimuth and zenith angles from location,

date, and Greenwich Mean Time (GMT), and loaded these values with the PARABOLA data.

In general, it took about 20 minutes for a PARABOLA data acquisition at one site and SZA. The

solar zenith would range at most 1.5 degrees during this time. The acquisition time increased during the

summer IFC in 1996, with SZA ranging as much as 3.7 degrees. This was because the Remote Sensing

Science (RSS)-01 team was also testing the new PARABOLA III instrument during this IFC, which

increased the overall data collection time.

The column PARABOLA MEAN VIEW_AZ ANG is reported as an angle relative to the solar

principal plane. To calculate this angle relative to north, add the SOLAR_AZ_ANG column to the

PARABOLA_MEAN_VIEW_AZ_ANG. If the result is greater than 360 degrees, subtract 360 to get the

correct value relative to north.

6.2 Field Notes

None given.

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The PARABOLA data were collected at the following three SSA locations along the tram cable

systems erected between the principal scaffold flux tower and a Rohn tower located approximately 70 m

from the flux tower.

• Old Aspen (SSA-9OA)

• Old Jack Pine (SSA-OJP)

• Old Black Spruce (SSA-OBS)

Page 6
The North American Datum of 1983 (NAD83) site coordinates:

UTM UTM UTM

Site Id Longitude Latitude Easting Northing Zone

SSA-9OA-PRB01 106.19779 ° W 53.62889 ° N 420790.5 5942899.9 13

SSA-OJP-PRB01 104.69203 ° W 53.91634 ° N 520227.7 5974257.5 13

SSA-OBS-PRB01 105.11779 ° W 53.98717 ° N 492276.5 5982100.5 13

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

The spatial resolution of the data ranges from 5.4 square meters at nadir to 15.6 square meters at an

angle of 45 degrees off-nadir and 46.6 square meters at 60 degrees off-nadir.

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

The overall period of PARABOLA data acquisition was from 16-Apr-1994 through 30-Jul-1996.

7.2.2 Temporal Coverage Map

The following table lists the data that were integrated into BORIS and are being provided on the

BOREAS Compact Disk-Read Only Memory (CD-ROM) series. For information about additional data

that were collected, see Sections 15 and 16.

NUMBER OF

SOLAR ZENITH PARABOLA

DATE IFC# SITE ANGLE VIEWS POSITION

16-Apr-1994 FFC-T SSA-OBS 4 Above Canopy

17-Apr-1994 FFC-T SSA-OBS 1 Above Canopy

19-Apr-1994 FFC-T SSA-OBS 6 Above Canopy

24-Apr-1994 FFC-T SSA-OA 4 Above Canopy

25-Apr-1994 FFC-T SSA-OA 1 Above Canopy

25-May-1994 1 SSA-OA 3 Above Canopy

26-May-1994 1 SSA-OA 3 Above Canopy

31-May-1994 1 SSA-OJP 8 Above Canopy

07-Jun-1994 1 SSA-OBS 8 Above Canopy

ll-Jun-1994 1 SSA-OA 5 Above Canopy

21-Jui-1994 2 SSA-OA 6 Above Canopy

25-Jui-1994 2 SSA-OJP 9 Above Canopy

04-Aug-1994 2 SSA-OBS 6 Above Canopy

31-Aug-1994 3 SSA-OA 6 Above Canopy

06-Sep-1994 3 SSA-OJP 6 Above Canopy

13-Sep-1994 3 SSA-OBS 6 Above Canopy

17-Sep-1994 3 SSA-OA 7 Above Canopy

05-Mar-1996 FFC-W SSA-OBS 3 Above Canopy

Page 7
08-Mar-1996 FFC-W SSA-OA 2 Above Canopy

12-Mar-1996 FFC-W SSA-OJP 2 Above Canopy

20-Jui-1996 IFC-2-96 SSA-OJP 1 Above Canopy

29-Jui-1996 IFC-2-96 SSA-OBS 1 Above Canopy

30-Jui-1996 IFC-2-96 SSA-OBS 1 Above Canopy

7.2.3 Temporal Resolution

PARABOLA data were collected at 5-degree SZA intervals, clouds permitting, from approximately

75 degrees SZA to solar noon. The PARABOLA measures a four-hemisphere area with 15-degree IFOV

sectors in 11 seconds. Measurements of the reflected radiance from a characterized barium sulfate

(BaSO4) reference panel were taken concurrently with PARABOLA measurements during the BOREAS

experiment in order to characterize spectral solar irradiance. These BaSO4 measurements were made

with a Barnes Modular Multiband Radiometer (MMR) mounted approximately 0.4 meters above a

horizontally leveled BaSO4 panel so that the MMR viewed the panel with a nadir view angle. The MMR

scanned the panel continuously throughout the day, and a Polycorder data logger was set to record the

measurements at a 1-minute time step interval.

7.3 Data Characteristics

7.3.1 Parameter/Variable

The parameters contained in the data files on the CD-ROM are:

Ba$O4 file:

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SOLAR ZEN ANG

PARABOLA CHI BASO4

PARABOLA CH2 BASO4

PARABOLA CH3 BASO4

CRTFCN CODE

REVISION DATE

Site data:

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME OBS

HEMISPHERE ID

PARABOLA NUM OBS

SOLAR ZEN ANG

SOLAR AZ ANG

PARABOLA MEAN VIEW ZEN ANG

PARABOLA MEAN VIEW AZ ANG

PARABOLA BIN VIEW ZEN ANG

PARABOLA BIN VIEW AZ ANG

MEAN PARABOLA CHI RAD

SDEV PARABOLA CHI RAD

MEAN PARABOLA CH2 RAD

Page 8
SDEV PARABOLA CH2 PAD

MEAN PARABOLA CH3 PAD

SDEV PARABOLA CH3 PAD

MEAN PARABOLA NDVI PAD

SDEV PARABOLA NDVI PAD

MEAN PARABOLA CHI REFL

MEAN PARABOLA CH2 REFL

MEAN PARABOLA CH3 REFL

MEAN PARABOLA NDVI REFL

CRTFCN CODE

REVISION DATE

7.3.2 Variable Description/Definition

The descriptions of the parameters contained in the data files on the CD-ROM are:

BaS04 file:

Column Name Description

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SOLAR ZEN ANG

PARABOLA CHI BASO4

PARABOLA CH2 BASO4

PARABOLA CH3 BASO4

CRTFCN CODE

REVISION DATE

The identifier assigned to the site by BOREAS,

in the format SSS-TTT-CCCCC, where SSS identifies

the portion of the study area: NSA, SSA, REG,

TRN, and TTT identifies the cover type for the

site, 999 if unknown, and CCCCC is the identifier

for site, exactly what it means will vary with

site type.

The identifier assigned to the sub-site by

BOREAS, in the format GGGGG-IIIII, where GGGGG is

the group associated with the sub-site instrument

e.g. HYD06 or STAFF, and IIIII is the identifier

for sub-site, often this will refer to an

instrument.

The date on which the data were collected.

The Greenwich Mean Time (GMT) when the data were

collected.

The angle from the surface normal (straight up)

to the sun during the data collection.

MMR measurements of a characterized barium

sulfate panel at the given date and time for

PARABOLA channel i.

MMR measurements of a characterized barium

sulfate panel at the given date and time for

PARABOLA channel 2.

MMR measurements of a characterized barium

sulfate panel at the given date and time for

PARABOLA channel 3.

The BOREAS certification level of the data.

Examples are CPI (Checked by PI), CGR (Certified

by Group), PRE (Preliminary), and CPI-??? (CPI

but questionable).

The most recent date when the information in the

referenced data base table record was revised.

Page 9
Site data:

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME OBS

HEMISPHERE ID

PARABOLA NUM OBS

SOLAR ZEN ANG

SOLAR AZ ANG

PARABOLA MEAN VIEW ZEN ANG

PARABOLA MEAN VIEW AZ ANG

PARABOLA BIN VIEW ZEN ANG

PARABOLA BIN VIEW AZ ANG

Description

The identifier assigned to the site by BOREAS,

in the format SSS-TTT-CCCCC, where SSS identifies

the portion of the study area: NSA, SSA, REG,

TRN, and TTT identifies the cover type for the

site, 999 if unknown, and CCCCC is the identifier

for site, exactly what it means will vary with

site type.

The identifier assigned to the sub-site by

BOREAS, in the format GGGGG-IIIII, where GGGGG is

the group associated with the sub-site

instrument e.g. HYD06 or STAFF, and IIIII is the

identifier for sub-site, often this will refer to

an instrument.

The date on which the data were collected.

The Greenwich Mean Time (GMT) when the data were

collected.

The hemisphere from which the instrument

collected data, where GR is ground and SK is sky.

The number of data points used for the averaged

data listed. A negative number means there was

a data gap and data was instead taken from the

opposite hemisphere. A zero means interpolated

data.

The angle from the surface normal (straight up)

to the sun during the data collection.

The azimuthal direction of the sun during data

collection expressed in clockwise increments from

north.

The mean zenith angle at which the radiant energy

was traveling when measured by the PARABOLA

instrument. The mean values were calculated from

measurements made within 15 degree zenith angle

incremental bins, with the view zenith values

increasing from the surface normal (straight up).

The mean azimuthal angle at which the radiant

energy was traveling when measured by the

PARABOLA instrument, relative to the solar

principal plane. The mean values were calculated

from measurements made within 30 degree azimuthal

angle incremental bins, with view azimuth values

increasing in a clockwise direction from the

solar position.

The center value of the 15 degree view zenith

angle bin from which the PARABOLA instrument viewed

the target. The center values increase relative

to surface normal (straight up).

The center value of the 30 degree view azimuth

angle bin from which the PARABOLA instrument

viewed the target. The center values increase in

a clockwise direction from the solar principal

plane.

Page 10
MEAN PARABOLA CHI RAD

SDEV PARABOLA CHI RAD

MEAN PARABOLA CH2 RAD

SDEV PARABOLA CH2 RAD

MEAN PARABOLA CH3 RAD

SDEV PARABOLA CH3 RAD

MEAN PARABOLA NDVI RAD

SDEV PARABOLA NDVI RAD

MEAN PARABOLA CHI REFL

MEAN PARABOLA CH2 REFL

MEAN PARABOLA CH3 REFL

MEAN PARABOLA NDVI REFL

CRTFCN CODE

REVISION DATE

The mean radiance value in PARABOLA channel 1

(.65-.67 microns).

The standard deviation of the radiance value in

PARABOLA channel 1 (.65-.67 microns) .

The mean radiance value in PARABOLA channel 2

(.81-.84 microns).

The standard deviation of the radiance value in

PARABOLA channel 2 (.81-.84 microns) .

The mean radiance value in PARABOLA channel 3

(1.62-1.69 microns).

The standard deviation of the radiance value in

PARABOLA channel 3 (1.62-1.69 microns) .

The mean NDVI calculated from PARABOLA radiance

in channels 1 and 2.

The standard deviation of NDVI calculated from

PARABOLA radiance in channels 1 and 2.

The mean reflectance factor in PARABOLA channel 1

(.65-.67 microns) calculated from PARABOLA

radiance values and MMR measurements of a

characterized barium sulfate panel.

The mean reflectance factor in PARABOLA channel 2

(.81-.84 microns) calculated from PARABOLA

radiance values and MMR measurements of a

characterized barium sulfate panel.

The mean reflectance factor in PARABOLA channel 3

(1.62-1.69 microns) calculated from PARABOLA

radiance values and MMR measurements of a

characterized barium sulfate panel.

The mean NDVI calculated from reflectance in

PARABOLA channels 1 and 2.

The BOREAS certification level of the data.

Examples are CPI (Checked by PI), CGR (Certified

by Group), PRE (Preliminary), and CPI-??? (CPI

but questionable).

The most recent date when the information in the

referenced data base table record was revised.

7.3.3 Unit of Measurement

The measurement units for the parameters contained in the data files on the CD-ROM are:

BaSO4 data:

Column Name Units

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SOLAR ZEN ANG

PARABOLA CHI BASO4

PARABOLA CH2 BASO4

PARABOLA CH3 BASO4

CRTFCN CODE

REVISION DATE

[none]

[none]

[DD-MON-YY]

[HHMM GMT]

[degrees]

[Watts] [meter^-2] [steradian^-l] [micrometer^-l]

[Watts] [meter^-2] [steradian^-l] [micrometer^-l]

[Watts] [meter^-2] [steradian^-l] [micrometer^-l]

[none]

[DD-MON-YY]

Page 11
Site data:

Column Name Units

SITE NAME

SUB SITE

DATE OBS

TIME OBS

HEMISPHERE ID

PARABOLA NUM OBS

SOLAR ZEN ANG

SOLAR AZ ANG

PARABOLA MEAN VIEW ZEN ANG

PARABOLA MEAN VIEW AZ ANG

PARABOLA BIN VIEW ZEN ANG

PARABOLA BIN VIEW AZ ANG

MEAN PARABOLA CHI RAD

SDEV PARABOLA CHI RAD

MEAN PARABOLA CH2 RAD

SDEV PARABOLA CH2 RAD

MEAN PARABOLA CH3 RAD

SDEV PARABOLA CH3 RAD

MEAN PARABOLA NDVI RAD

SDEV PARABOLA NDVI RAD

MEAN PARABOLA CHI REFL

MEAN PARABOLA CH2 REFL

MEAN PARABOLA CH3 REFL

MEAN PARABOLA NDVI REFL

CRTFCN CODE

REVISION DATE

[none]

[none]

[DD-MON-YY]

[HHMM GMT]

[none]

[counts]

[degrees]

[degrees]

[degrees]

[degrees]

[degrees]

[degrees]

[Watts] [meter^-2] [steradian^-l] [micrometer ^-

[Watts] [meter^-2] [steradian^-l] [micrometer ^-

[Watts] [meter^-2] [steradian^-l] [micrometer ^-

[Watts] [meter^-2] [steradian^-l] [micrometer ^-

[Watts] [meter^-2] [steradian^-l] [micrometer ^-

[Watts] [meter^-2] [steradian^-l] [micrometer ^-

[none]

[none]

[percent]

[percent]

[percent]

[none]

[none]

[DD-MON-YY]

7.3.4 Data Source

The sources of the parameter values contained in the data files on the CD-ROM are:

BaSO4 data:

Column Name Data Source

1]

1]

1]

1]

1]

1]

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SOLAR ZEN ANG

PARABOLA CHI BASO4

PARABOLA CH2 BASO4

PARABOLA CH3 BASO4

CRTFCN CODE

REVISION DATE

[Assigned by BORIS Staff]

[Assigned by BORIS Staff]

[Controller]

[Controller]

[Calculated]

[PARABOLA]

[PARABOLA]

[PARABOLA]

[Assigned by BORIS Staff]

[Assigned by BORIS Staff]

Page 12
Site data:

Column Name Data Source

SITE NAME [Assigned by BORIS Staff]

SUB SITE [Assigned by BORIS Staff]

DATE OBS [Controller]

TIME OBS [Controller]

HEMISPHERE ID [Instrument operator]

NUM OBS [Controller]

SOLAR ZEN ANG [Calculated]

SOLAR AZ ANG [Calculated]

PARABOLA MEAN VIEW ZEN ANG [PARABOLA]

PARABOLA MEAN VIEW AZ ANG [PARABOLA]

PARABOLA BIN VIEW ZEN ANG [PARABOLA]

PARABOLA BIN VIEW AZ ANG [PARABOLA]

MEAN PARABOLA CHI RAD [PARABOLA]

SDEV PARABOLA CHI RAD [PARABOLA]

MEAN PARABOLA CH2 RAD [PARABOLA]

SDEV PARABOLA CH2 RAD [PARABOLA]

MEAN PARABOLA CH3 RAD [PARABOLA]

SDEV PARABOLA CH3 RAD [PARABOLA]

MEAN PARABOLA NDVI RAD [PARABOLA]

SDEV PARABOLA NDVI RAD [PARABOLA]

MEAN PARABOLA CHI REFL [PARABOLA]

MEAN PARABOLA CH2 REFL [PARABOLA]

MEAN PARABOLA CH3 REFL [PARABOLA]

MEAN PARABOLA NDVI REFL [PARABOLA]

CRTFCN CODE [Assigned by BORIS Staff]

REVISION DATE [Assigned by BORIS Staff]

7.3.5 Data Range

The following table gives information about the parameter values found in the data files on the

CD-ROM.

BaS04 data:

Column Name

Minimum Maximum Missng Unrel Below

Data Data Data Data Detect

Value Value Value Value Limit

Data

Not

Cllctd

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SOLAR ZEN ANG

PARABOLA CHI BASO4

PARABOLA CH2 BASO4

PARABOLA CH3 BASO4

CRTFCN CODE

REVISION DATE

SSA-9OA-FLXTR SSA-OJP-FLXTR None None None

RSS01-PRB01 RSS01-PRB01 None None None

16-APR-94 30-JUL-96 None None None

ii 2356 None None None

33.241 76.959 None None None

90.73 371.91 None None None

62.7 255.76 None None None

14.31 57.04 None None None

CPI CPI None None None

10-NOV-98 10-NOV-98 None None None

None

None

None

None

None

None

None

None

None

None

Page 13
Site data:

Column Name

Minimum Maximum Missng

Data Data Data

Value Value Value

Unrel Below Data

Data Detect Not

Value Limit Cllctd

SITE NAME SSA-9OA-FLXTR

SUB SITE RSS01-PRB01

DATE OBS 16-APR-94

TIME OBS ii

HEMISPHERE ID GR

PARABOLA NUM OBS -70

SOLAR ZEN ANG 33.241

SOLAR AZ ANG 75.893

PARABOLA MEAN VIEW 0

ZEN ANG

PARABOLA MEAN VIEW 0

AZ ANG

PARABOLA BIN VIEW 0

ZEN ANG

PARABOLA BIN VIEW AZ 0

ANG

MEAN PARABOLA CHI 1.18

RAD

SDEV PARABOLA CHI 0

RAD

MEAN PARABOLA CH2 2.19

RAD

SDEV PARABOLA CH2 0

RAD

MEAN PARABOLA CH3 .09

RAD

SDEV PARABOLA CH3 0

RAD

MEAN PARABOLA NDVI -. 714

RAD

SDEV PARABOLA NDVI 0

RAD

MEAN PARABOLA CHI .9

REFL

MEAN PARABOLA CH2 i. 7

REFL

MEAN PARABOLA CH3 .3

REFL

MEAN PARABOLA NDVI -.378

REFL

CRTFCN CODE CPI

REVISION DATE 10-NOV- 98

SSA-OJP-FLXTR None

RSS01-PRB01

30-JUL-96

2356

SK

73

76.959

273 583

8O

360

75

360

280 31

170

139 91

89.7

59.49

38.78

.889

.45

122.6

97.1

129.3

.925

CPI

12-NOV-98

None None None

None None None None

None None None None

None None None None

None None None None

None None None None

None None None None

None None None None

None None None None

None None None None

None None None None

None None None None

-999 None None None

None None None None

-999 None None None

None None None None

-999 None None None

None None None None

-999 None None None

None None None None

-999 None None None

-999 None None None

-999 None None None

-999 None None None

None None None None

None None None None

Minimum Data Value -- The minimum value found in the column.

Maximum Data Value -- The maximum value found in the column.

Missng Data Value -- The value that indicates missing data. This is used to

indicate that an attempt was made to determine the

parameter value, but the attempt was unsuccessful.

Unrel Data Value -- The value that indicates unreliable data. This is used

Page 14
Below Detect Limit

Data Not Cllctd

to indicate an attempt was made to determine the

parameter value, but the value was deemed to be

unreliable by the analysis personnel.

The value that indicates parameter values below the

instruments detection limits. This is used to

indicate that an attempt was made to determine the

parameter value, but the analysis personnel determined

that the parameter value was below the detection

limit of the instrumentation.

This value indicates that no attempt was made to

determine the parameter value. This usually

indicates that BORIS combined several similar but

not identical data sets into the same data base table

but this particular science team did not

measure that parameter.

Blank -- Indicates that blank spaces are used to denote that type of value.

N/A -- Indicates that the value is not applicable to the respective column.

None -- Indicates that no values of that sort were found in the column.

7.4 Sample Data Record

The following is a sample of the first few records from the data table on the CD-ROM:

BaS04 data:

SITE NAME, SUB SITE, DATE OBS,TIME OBS,SOLAR ZEN ANG,PARABOLA CHI BASO4,

PARABOLA CH2 BASO4,PARABOLA CH3 BASO4,CRTFCN CODE, REVISION DATE

'SSA-OBS-FLXTR', 'RSS01-PRB01', 16-APR-94,2156,56.002,243.76, 182.1,41.63, 'CPI',

10-NOV-98

'SSA-OBS-FLXTR', 'RSS01-PRB01'

10-NOV-98

'SSA-OBS-FLXTR', 'RSS01-PRB01'

10-NOV-98

'SSA-OBS-FLXTR', 'RSS01-PRB01'

10-NOV-98

'SSA-OBS-FLXTR', 'RSS01-PRB01'

10-NOV-98

,16-APR-94,2219,58.881,223.42,166.92,38.27, 'CPI'

,16-APR-94,2312,66.054,170.71,128.07,28.73, 'CPI'

,16-APR-94,2356,72.37,125.77,95.11,20.79, 'CPI',

,17-APR-94,22,76.18,90.73,69.13,14.31, 'CPI'

Site data:

SITE NAME, SUB SITE, DATE OBS,TIME OBS,HEMISPHERE ID,PARABOLA NUM OBS,

SOLAR ZEN ANG, SOLAR AZ ANG,PARABOLA MEAN VIEW ZEN ANG,PARABOLA MEAN VIEW AZ ANG,

PARABOLA BIN VIEW ZEN ANG,PARABOLA BIN VIEW AZ ANG,MEAN PARABOLA CHI RAD

SDEV PARABOLA CHI RAD,MEAN PARABOLA CH2 RAD,SDEV PARABOLA CH2 RAD,

MEAN PARABOLA CH3 RAD, SDEV PARABOLA CH3 RAD, MEAN PARABOLA NDVI RAD,

SDEV PARABOLA NDVI RAD,MEAN PARABOLA CHI REFL,MEAN PARABOLA CH2 REFL,

MEAN PARABOLA CH3 REFL,MEAN PARABOLA NDVI REFL,CRTFCN CODE,REVISION DATE

'SSA-9OA-FLXTR', 'RSS01-PRB01',21-JUL-94, 1419, 'GR', 8, 63. 6, 90. 755, 14 .2, 114 8, 0, 0,

3.38,1.0,47.7,12.5,3.64, .91, .868, .01,1.9,43.2,12.8, .915, 'CPI' , 10-NOV-98

'SSA-9OA-FLXTR', 'RSS01-PRB01',21-JUL-94, 1419, 'GR',-9, 63.6, 90.755, 16.8, 6.3, 15, 0,

2.93,1.4,39.71,18.7,3.07,1.07, .861, .02,1.7,35.9,10.8, .911, 'CPI' , 10-NOV-98

'SSA-9OA-FLXTR', 'RSS01-PRB01',21-JUL-94, 1419, 'GR', ii, 63.6, 90.755,45.3, 12.4,45,

0,3.58, .7,38.51,9.5,3.23, .56, .829, .04,2.0,34.8,11.4, .89, 'CPI' , 10-NOV-98

'SSA-9OA-FLXTR', 'RSS01-PRB01',21-JUL-94, 1419, 'GR', ii, 63.6, 90.755,30.7,7.5,30, 0,

2.87, .6,35.29,7.3,2.81, .48, .848, .03,1.6,31.9,9.9, .903, 'CPI' , 10-NOV-98

Page 15
8. Data Organization

8.1 Data Granularity

The unit of data tracked by BORIS is all the data collected at a site on a given day or for a given time

period.

8.2 Data Format(s)

The CD-ROM files contain American Standard Code for Information Interchange (ASCII) numerical

and character fields of varying length separated by commas. The character fields are enclosed with

single apostrophe marks. There are no spaces between the fields.

Each data file on the CD-ROM has four header lines of Hyper-Text Markup Language (HTML) code

at the top. When viewed with a Web browser, this code displays header information (data set title,

location, date, acknowledgments, etc.) and a series of HTML links to associated data files and related

data sets. Line 5 of each data file is a list of the column names, and line 6 and following lines contain the

actual data.

9. Data Manipulations

9.1 Formulae

None given.

9.1.1 Derivation Techniques and Algorithms

Characterization of spectral solar irradiance was carried out using two separate techniques. First, a

Barnes MMR was mounted above a BaSO4 reference panel, both clamped to the tower above the canopy

top in order to sample the spectral downwelling irradiance. The MMR and PARABOLA were

intercalibrated at the GSFC 1.8-m integrating sphere radiance source. The MMR measurements of the

BaSO4 panel were corrected for reflectance anisotropy, which had been previously characterized using

the procedure of Jackson et al. (1987). However, because of different band passes of the PARABOLA

and MMR instruments (e.g., PARABOLA 810-840 nm versus MMR 750-880 rim), the MMR response

to different total columnar atmospheric water vapor amount differed from PARABOLA's response due

to different water vapor transmittances. Therefore, the cloudless sky spectral irradiance model was used

(an integral part of the Second Simulation of the Satellite Signal in the Solar Spectrum (6S) model

(Vermote et al., 1997)). The model was used with measured aerosol optical depths, total water vapor,

and aerosol volume size distributions from Cimel automatic spectral solar radiometers located in the

BOREAS SSA (Markham et al. (1997)). The total ozone amount used in the 6S model calculations was

climatological means from London et al. (1976). For PARABOLA channel 1 (650-670 rim; with no

water vapor absorption), the irradiances computed from 6S agreed very well with MMR measured

irradiances, typically within 2-3%. However, for PARABOLA channel 2 (810-840 rim), the differences

between the two techniques varied from approximately 1% to 15% depending on water vapor amount

and SZA. Differences between the two techniques for PARABOLA channel 3 (1620-1690 rim) were

intermediate to those found for the other channels, since the water vapor transmittance differences for

the two instrument band passes were less in channel 3 than for channel 2. Therefore, because of the

differing effects of the water vapor transmittances for the differing band passes of the two instruments,

the spectral irradiance computed from 6S was used in the calculations of reflectance factors.

9.2 Data Processing Sequence

9.2.1 Processing Steps

Directional reflectances are normally computed as hemispherical-directional reflectance factors using

the PARABOLA directional radiance measurements from the ground-looking hemisphere. The

ground-looking hemisphere values are divided by the PARABOLA-derived incident irradiance as

computed from the PARABOLA sky irradiance data or from a calibrated BaSO4 painted reference

Page 16
standardpanel.

ThePARABOLAdatascanstakenfrom the11subsitesateachSZAmeasurementsequenceare

combinedin softwarewrittento analyzethebidirectionalreflectancedistributioncharacteristicsof the

site.Thisprocedurealsoenablesmoreaccuratesamplingof the"hot spot"effectsandtheaureole

surroundingtheSun.

BecausethePARABOLA observationsarenot acquiredatequalanglesof azimuthandzenith,and

becausemostuserspreferthedataat equalintervals,thesedatahavebeenaveragedintostandardbins.

A dataaggregationschemewasestablishedthatdefinesbinsof 30degreesof azimuthand15

degreesof zenithfor eachof thesky andgroundhemispheres,resultingin (360/30)* (90/15)bins(i.e.,

12* 6 = 76bins)perhemisphere.Theobservedpixelsfalling in agivenbin wereaveragedto derivethe

suppliedradiancevalue.Thenumberof pixelsusedin computingthebin averageiscontainedin the

columnNUM_OBS.Datagapsresultingfrom thescanningpattern,shadowing,orcontaminationof the

pixelby instrumentsupportequipmentor operatorsand/orotheranomaliesarehandledasfollows:

• If dataareavailablefromtheoppositesideof thehemisphere,thedatagapis filled by placing

theinformationfrom theoppositesideintotheemptyarea.Notethatthisassumessymmetryin

theazimuthplanewith respecto thesolarprincipalplane.Theseinstancesareidentifiedwith a

negativenumberof observations.

• If nodataareavailablefrom theoppositesideof thehemisphere,aninterpolatedvalueis used.

Theseinstancesareidentifiedwith azeroin thenumberof observationscolumn.

BORISprocessingstepsfor PARABOLAdata:

• ReformattedthePARABOLA .AFFfiles to adddate,time,hemisphere,solarazimuth,and

reflectancecolumns.

• ComputedtheSZAandsolarazimuthanglesbasedonsitelocation,observationdate,and

observationtime.ReplacedtheSZAgivenwiththatwhichwascomputedbecausetheanglesin

theoriginalfileswerecomputedfrom anendtimeratherthanthemid-pointof thedata

collectiontime.Enteredthesolarazimuth.

• Calculatedreflectancefrom radianceusingtheBariumSulfatemeasurementsgiven.TheBaSO4

measurement valuesarecontainedwithin thetableRSS01_PARABOLA_BASO4_REF.

• ComputedNDVI fromthereflectancevalues.

• Loadedandinventoriedthedatain to theBORISdatabase.

• ExtractedthePARABOLAdatato createfiles for eachdateandsite.

9.2.2 Processing Changes

Nonegiven.

9.3 Calculations

SeeSection9.1.1.

9.3.1 Special Corrections/Adjustments

Becausemostuserspreferthedataatequalintervalsof viewing angles,anaverageddatasetis

provided.Thepixelsfalling in acell orbin of fixedoff-nadirandazimuthwidth areaveraged.The

centersof thesebinsareatintervalsof 15degreesin off-nadirand30degreesin azimuthalplane.One of

the columns gives the number of points used in computing the average values for that bin. If there is a

data gap caused by the scanning pattern, shadowing of the target by the instrument, or its support

equipment (or "contaminated" by the instrument or operators), or other anomalies (e.g., instrument

"noise"), the gap is filled by substituting the data point from the opposite side of the hemisphere

(assumes symmetry in azimuth plane with respect to the solar principal plane). To identify such cases,

the number of data points averaged is given as negative (mirror image) values. If for some reason there

are no data for substitution then an interpolated value is used. Because the interpolated values are not

real measured values, a zero is placed in the column specifying the number of points averaged in order

to caution the user about this potential reliability factor.

Page 17
9.3.2 Calculated Variables

See Section 9.1.1.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

None given.

10.2 Quality Assessment

The PARABOLA instrument data quality and accuracy are discussed in detail in the following

references:

Deering, D.W. and P. Leone. 1986. A sphere-scanning radiometer for rapid directional measurements

of sky and ground radiance. Remote Sens. Environ. 19:1-24.

Deering, D.W., E.M. Middleton, J.R. Irons, B.L. Blad, E.A. Walter-Shea, C.J. Hays, C. Walthall,

T.F. Eck, S.P. Ahmad, and B.P. Banerjee. 1992. Prairie grassland bidirectional reflectances measured

by different instruments at the FIFE site, Journal of Geophysical Research 97 (D 17:18,887-18,903.

10.2.1 Data Validation by Source

None given.

10.2.2 Confidence Level/Accuracy Judgment

None given.

10.2.3 Measurement Error for Parameters

None given.

10.2.4 Additional Quality Assessments

None given.

10.2.5 Data Verification by Data Center

BORIS staff" applied a general Quality Assurance (QA) procedure to the data before the steps

described in Section 9 were applied.

11. Notes

11.1 Limitations of the Data

None given.

11.2 Known Problems with the Data

It is recommended that users read Deering and Leone (1986) before using the PARABOLA data.

11.3 Usage Guidance

None given.

11.4 Other Relevant Information

None given.

Page 18
12. Application of the Data Set

Data can be used to characterize directional anisotropy of solar radiance reflected from terrestrial surfaces

and Bidirectional Reflectance Distribution Function (BRDF) modeling and validation. PARABOLA data

can also be used to estimate hemispherical reflectance (albedo).

None given.

13. Future Modifications and Plans

14.1 Software Description

None given.

14.2 Software Access

None given.

14. Software

15. Data Access

The PARABOLA SSA surface reflectance and transmittance data are available from the Earth Observing

System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed

Active Archive Center (DAAC).

15.1 Contact Information

For BOREAS data and documentation please contact:

ORNL DAAC User Services

Oak Ridge National Laboratory

P.O. Box 2008 MS-6407

Oak Ridge, TN 37831-6407

Phone: (423) 241-3952

Fax: (423) 574-4665

E-mail: ornldaac@ornl.gov or ornl@eos.nasa.gov

15.2 Data Center Identification

Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory

(ORNL) Distributed Active Archive Center (DAAC) for Biogeochemical Dynamics

http://www-eo sdis. ornl.gov/.

15.3 Procedures for Obtaining Data

Users may obtain data directly through the ORNL DAAC online search and order system

[http://www-eosdis.ornl.gov/] and the anonymous FTP site [ftp://www-eosdis.ornl.gov/data/] or by

contacting User Services by electronic mail, telephone, fax, letter, or personal visit using the contact

information in Section 15.1.

15.4 Data Center Status/Plans

The ORNL DAAC is the primary source for BOREAS field measurement, image, GIS, and

hardcopy data products. The BOREAS CD-ROM and data referenced or listed in inventories on the

CD-ROM are available from the ORNL DAAC.

Page 19
16. Output Products and Availability

16.1 Tape Products

None.

16.2 Film Products

None.

16.3 Other Products

These data are available on the BOREAS CD-ROM series. Note that the other ('FFL') data sets

(described below) are available but were not loaded into the BOREAS data base and are not contained on

the CD-ROM series; however, they are available from Oak Ridge National Laboratory (ORNL) (see

Section 15).

For PARABOLA-data users there are two output PARABOLA data formats that have been created,

which have the filename extensions 'AFF' and 'FFL'. The data loaded into the BOREAS data base and

described in section 7 were the 'AFF' type. The 'FFL' data type is a complete, but filtered, data set

consisting of almost all of the individual pixels from the replicate scans (usually 11 for BOREAS sites)

of the same target. Because of the scanning pattern of the PARABOLA, the pixels are not at equidistant

angles in the off-nadir or azimuth viewing planes. It is recommended that users familiarize themselves

with the instrument by reviewing the article by Deering and Leone (1986) before using the PARABOLA

data.

OUTPUT FORMAT FOR FILE 'filename.FFL':

The first record gives the following HEADER INFORMATION:

Filename or data ID, extracted from first input filename

Hemisphere-ID, 'GR' for ground, ..'SK' for sky

Latitude of the target site (-ve for south)

Longitude of the target (-ve for west of Greenwich)

Date of the observations (e.g., 06-04-1987)

Local time of the measurements, hours:rain (e.g., 15:22)

Julian day (e.g., 155)

GMT of measurements, hours:rain (e.g., 20:22)

SZA

Total hemispheric diffuse flux (upwelling or downwelling (W/mZ/lam) for channel 1)

Total hemispheric diffuse flux (upwelling or downwelling (W/mZ/lam) for channel 2)

Total hemispheric diffuse flux (upwelling or downwelling (W/mZ/lam) for channel 3)

Please note that for the BOREAS data set, a negative sign is put in front of these flux values to caution

the user that these values will be updated in the near future once the algorithm is tested and validated for

the extrapolation mechanism used beyond 75-degree off-nadir view angles.

DATA RECORDS follow the header record. First, all GROUND pixels are written; then the SKY

pixels are written following the ground pixels. However, before starting the first sky pixel, the header

record is repeated.

Page 20
17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Deering, D.W. and P. Leone. 1986. A sphere-scanning radiometer for rapid directional measurements

of sky and ground radiance. Remote Sens. Environ. 19:1-24.

17.2 Journal Articles and Study Reports

Ahmad, S.P., E.M. Middleton, and D.W. Deering. 1987. Computation of diffuse sky irradiance from

multidirectional radiance measurements. Remote Sens. Environ. 21:185-200.

Deering, D.W. 1989. Field measurements of bidirectional reflectance. In: Theory and Applications of

Optical Remote Sensing. John Wiley & Sons, Inc. pp. 14-65.

Deering, D.W. and T.F. Eck. 1987. Atmospheric optical depth effects on angular anisotropy of plant

canopy reflectance. Int. J. Remote Sens. 8:893-916.

Deering, D.W., E.M. Middleton, J.R. Irons, B.L. Blad, E.A. Walter-Shea, C.J. Hays, C.W. Walthall,

T.F. Eck, S.P. Ahmad, and B.P. Banerjee. 1992. Prairie grassland bidirectional reflectance measured

by different instruments at the FIFE site. Journal of Geophysical Research 97(D 17): 18,887-18,903.

Deering, D.W., T.F. Eck, and J. Otterman. 1990. Bidirectional reflectances of three desert surfaces and

their characterization through model inversion. J. Agric. and Forest Meteorol. 52:71-93.

Irons, J.R., F.G. Huegel, and R.R. Irish. 1989. Prairie grass hemispherical reflectances from airborne

multi-directional observations. Proc. of 19th Conf. on Agriculture and Forest Meteorology and the

Ninth Conf. on Biometeorology and Aerobiology. March 7-10, 1989. Charleston, SC. Published by

American Meteorological Society, Boston, MA.

Irons, J.R., R.A. Weismiller, and G.W. Peterson. 1989. Soil reflectance. G. Asrar (ed.). In Theory

and Applications of Optical Remote Sensing. John Wiley & Sons. New York. pp. 66-106.

Jackson, R.D., M.S. Moran, P.N. Slater, and S.F. Bigger. 1987. Field calibration of reference

reflectance panels. Remote Sens. Environ., 17:37-53.

Leshkevich, G.A., D.W. Deering, T.F. Eck, and S.P. Ahmad. 1990. Diurnal patterns of the

bidirectional reflectance of freshwater ice. Annals of Glaciol. 14:153-157.

London, J., R.D. Bojkov, S. Oltmans, and J.I. Kelley. 1976. Atlas of the global distribution of total

ozone July 1957-June 1967. NCAR Tech. Note 113+STR, Boulder, CO. 276 pp.

Markham, B.L., J.S. Schafer, B.N. Holben, and R.N. Halthore. 1997. Atmospheric aerosol and water

vapor characteristics over north central Canada during BOREAS. Journal of Geophysical Research

102(D24):29,737-29,745.

Middleton, E.M., D.W. Deering, and S.P. Ahmad. 1987. Surface anisotropy and hemispheric

reflectance of semi-arid plant communities. Remote Sens. Environ. 23:193-212.

Newcomer, J., D. Landis, S. Conrad, S. Curd, K. Huemmrich, D. Knapp, A. Morrell, J. Nickeson,

A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall, and P. Sellers, eds. 2000. Collected Data of The

Boreal Ecosystem-Atmosphere Study. NASA. CD-ROM.

Otterman, J., D.W. Deering, and T.F. Eck. 1987. Techniques of Ground-Truth Measurements of

Desert-Scrub Structure. Advances in Space Res. 7:153-158.

Page 21
Sellers,P.andF.Hall. 1994.BorealEcosystem-AtmosphereStudy:ExperimentPlan.Version

1994-3.0,NASA BOREASReport(EXPLAN 94).

Sellers,P.andF.Hall. 1996.BorealEcosystem-AtmosphereStudy:ExperimentPlan.Version

1996-2.0,NASA BOREASReport(EXPLAN 96).

Sellers,P.,F. Hall, andK.F. Huemmrich.1996.BorealEcosystem-AtmosphereStudy:1994

Operations.NASA BOREASReport(OPSDOC94).

Sellers,P.,F. Hall, andK.F. Huemmrich.1997.BorealEcosystem-AtmosphereStudy:1996

Operations.NASA BOREASReport(OPSDOC96).

Sellers,P.,F. Hall, H. Margolis, B. Kelly, D.Baldocchi,G. denHartog,J.Cihlar, M.G. Ryan,B.

Goodison,P. Crill, K.J.Ranson,D. Lettenmaier,andD.E. Wickland. 1995.Theboreal

ecosystem-atmospherestudy(BOREAS):anoverviewandearlyresultsfrom the1994field year.

Bulletinof theAmericanMeteorologicalSociety.76(9):1549-1577.

Sellers,P.J.,F.G.Hall, R.D.Kelly, A. Black, D. Baldocchi,J. Berry, M. Ryan,K.J. Ranson,P.M.

Crill, D.P.Lettenmaier,H. Margolis,J.Cihlar, J.Newcomer,D. Fitzjarrald,P.G.Jarvis,S.T.

Gower,D. Halliwell, D. Williams, B. Goodison,D.E.Wickland,andF.E.Guertin.1997.BOREASin

1997:ExperimentOverview,ScientificResultsandFutureDirections.Journalof GeophysicalResearch

102(D24):28,731-28,770.

Shephard,M.K., R.E.Arvidson,E.A. Guinness,andD.W. Deering.1991.Application of Hapke

PhotometricModelto LunarLakePlayausingPARABOLAbidirectionalreflectancedata.Geophys.

Res.Letters18:2241-2244.

Vermote,E.,D. Tanre,andJ.J.Morcrette.1997.Secondsimulationof thesatellitesignalin thesolar

spectrum6S:anoverview.IEEETrans.Geosci.RemoteSens.vol. 35no. 3, pp.675.

Walter-Shea,E.A. andL.L. Biehl. 1990.Measuringvegetationspectralproperties.RemoteSensing

Review.5:179-205.

Walter-Shea,E.A., J.M.Norman,andB.L. Blad. 1989.Leafbidirectionalreflectanceandtransmittance

in cornandsoybean.RemoteSensingof Environment.29:161-174.

17.3 Arehive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

Page 22
19. List of Acronyms

6S

ASAS

ASCII

AVIRIS

BIL

BOREAS

BORIS

BRDF

BSQ

CASI

CD-ROM

DAAC

EOS

EOSDIS

FFC-T

FFC-W

FOV

GIS

GMT

GSFC

HTML

IFC

IFOV

MMR

NAD83

NASA

NDVI

NSA

OA

OBS

OJP

ORNL

PANP

PAR

- Second Simulation of the Satellite Signal in the Solar Spectrum

- Advanced Solid-state Array Spectroradiometer

- American Standard Code for Information Interchange

- Airborne Visible InfraRed Imaging Spectrometer

- Band Interleaved by Line

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Bidirectional Reflectance Distribution Function

- Band Sequential

- Compact Airborne Spectrographic Imager

- Compact Disk-Read-Only Memory

- Distributed Active Archive Center

- Earth Observing System

- EOS Data and Information System

- Focused Field Campaign-Thaw

- Focused Field Campaign-Winter

- Field of view

- Geographic Information System

- Greenwich Mean Time

- Goddard Space Flight Center

- HyperText Markup Language

- Intensive Field Campaign

- Instantaneous Field of View

- Modular Multiband Radiometer

- North American Datum of 1983

- National Aeronautics and Space Administration

- Normalized Difference Vegetation Index

- Northern Study Area

- Old Aspen

- Old Black Spruce

- Old Jack Pine

- Oak Ridge National Laboratory

- Prince Albert National Park

- Photosynthetically Active Radiation

PARABOLA - Portable Apparatus for Rapid Acquisitions of BiDirectional

Observations of Land and Atmosphere

POLDER

QA

RSS

SSA

SZA

TM

URL

UTM

- Polarization and Directionality of Earth Reflectances

- Quality Assurance

- Remote Sensing Science

- Southern Study Area

- Solar Zenith Angle

- Thematic Mapper

- Uniform Resource Locator

- Universal Transverse Mercator

Page 23
20. Document Information

20.1 Document Revision Date(s)

Written: 18-Nov- 1994

Last Updated: 13-Aug- 1999

20.2 Document Review Date(s)

BORIS Review: 28-Nov- 1998

Science Review: 29-Jun- 1998

20.3 Document ID

20.4 Citation

When using these data, please include the following acknowledgment as well as citations of relevant

papers in Section 17.2:

The surface reflectance and transmitted radiance measured by PARABOLA were collected and

analyzed by Dr. Donald W. Deering, Thomas F. Eck, Dr. Suraiya P. Ahmad, and Babu Banerjee as part

of the Remote Sensing Science (RSS-01) study of the BOREAS experiment.

If using data from the BOREAS CD-ROM series, also reference the data as:

Deering, D.W., E.M. Middleton, S.P. Ahmad, and T.F. Eck, "Radiative Transfer Characteristics of

Boreal Forest Canopies and Algorithms for Energy Balance and PAR Absorption." In Collected Data of

The Boreal Ecosystem-Atmosphere Study. Eds. J. Newcomer, D. Landis, S. Conrad, S. Curd, K.

Huemmrich, D. Knapp, A. Morrell, J. Nickeson, A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall,

and P. Sellers. CD-ROM. NASA, 2000.

Also, cite the BOREAS CD-ROM set as:

Newcomer, J., D. Landis, S. Conrad, S. Curd, K. Huemmrich, D. Knapp, A. Morrell, J.

Nickeson, A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall, and P. Sellers, eds. Collected Data of

The Boreal Ecosystem-Atmosphere Study. NASA. CD-ROM. NASA, 2000.

20.5 Document Curator

20.6 Document URL

Page 24
REPORT DOCUMENTATION PAGE FormApproved

OMB No. 0704-0188

Public reporting burden for this collection of informationis estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this

collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson

Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.

1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

July 2000 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Technical Report Series on the Boreal Ecosystem-Atmosphere Study (BOREAS)

BOREAS RSS-1 PARABOLA SSA Surface Reflectance and Transmittance

923

Data

6. AUTHOR(S) RTOP: 923-462-33-01

Donald D. Deering, Thomas E Eck, and Babu Banerjee

Forrest G. Hall and Jaime Nickeson, Editors

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

Goddard Space Flight Center

Greenbelt, Maryland 20771

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

National Aeronautics and Space Administration

Washington, DC 20546-0001

8. PEFORMING ORGANIZATION

REPORT NUMBER

2000-03136-0

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

TM--2000-209891

Vol. 42

11. SUPPLEMENTARY NOTES

T.F.Eck, B. Banerjee, and J. Nickeson: Raytheon ITSS

12a. DISTRIBUTION / AVAILABILITY STATEMENT

Unclassifie_Unlimited

Subject Category: 43

Report available from the NASA Center for AeroSpace Information,

7121 Standard Drive, Hanover, MD 21076-1320. (301) 621-0390.

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The BOREAS RSS-1 team collected surface reflectance and transmittance data from three forested

sites in the SSA. This data set contains averaged reflectance factors and transmitted radiances measured by the PARABOLA instrument at selected sites in the BOREAS SSA at different view angles

and at three wavelength bands throughout the day. PARABOLA measurements were made during each

of the three BOREAS IFCs during the growing season of 1994 at three SSA tower flux sites as well as

during the FFC-T. Additional measurements were made in early and mid-1996 during the FFC-W and

during IFC-2. The data are stored in tabular ASCII files.

14. SUBJECT TERMS

BOREAS, remote sensing science, PARABOLA instrument.

17. SECURITY CLASSIFICATION

OF REPORT

Unclassified

NSN 7540-01-280-5500

18. SECURITY CLASSIFICATION

OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

15. NUMBER OF PAGES

24

16. PRICE CODE

20. LIMITATION OF ABSTRACT

UL

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39.18

298-102