NASA/TMm2000-209891, Vol. 45

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 45

BOREAS RSS-3 Atmospheric Measurements

from a Helicopter-Mounted Sunphotometer

Charles L. Walthall, U.S.D.A. Agricultural Research Service, Beltsville, Maryland

Sara Loechel, University of Maryland

Rangasayi Halthore, Brookhaven National Laboratory

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

July 2000

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NASA/TMm2000-209891, Vol. 45

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 45

BOREAS RSS-3 Atmospheric Measurements

from a Helicopter-Mounted Sunphotometer

Charles L. Walthall, U.S.D.A. Agricultural Research Service, Beltsville, Maryland

Sara Loechel, University of Maryland

Rangasayi Halthore, Brookhaven National Laboratory

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

July 2000
NASA Center for AeroSpace Information

7121 Standard Drive

Hanover, MD 21076-1320

Price Code: A17

Available from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Price Code: A10
BOREAS RSS-3 Atmospheric Measurements from a Helicopter-Mounted

Sunphotometer

Charles L. Walthall, Sara Loechel, Rangasayi Halthore

Summary

The BOREAS RSS-3 team collected and processed helicopter-based measurements of atmospheric

conditions to estimates of aerosol optical thickness and atmospheric water vapor. The automatic

sun-tracking photometer for helicopters was deployed during all three 1994 IFCs at numerous tower

and auxiliary sites in both the NSA and the SSA. Six spectral channels (440, 540, 613,670, 870, and

1030 nm) were chosen to span the visible and NIR wavelengths and to avoid gaseous absorption. One

additional channel, 940 nm, was selected to measure the water column abundance above the helicopter

platform. The data are stored in tabular ASCII files.

Note: An extensive helicopter log (in Acrobat format) is available for the 1994 IFC's.

Environmental, technical, instrumental, and operational conditions are noted for each observation

where applicable. It is strongly recommended that any researcher doing extended work with this data

set review this helicopter log.

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-03 Atmospheric Measurements from a Helicopter-Mounted Sunphotometer

1.2 Data Set Introduction

The Remote Sensing Science (RSS)-03 helicopter-based optical depth measurements are used to

perform atmospheric corrections to radiance to obtain at-ground reflectance estimates from the

helicopter-mounted radiometers. Sunphotometer measurements were taken from a helicopter platform

at BOReal Ecosystem-Atmosphere Study (BOREAS) forested tower and auxiliary sites simultaneously

Page 1
with radiometricgroundmeasurementsfrom thesameplatform.Theinstrumentationusedwas

designedanddevelopedatNationalAeronauticsandSpaceAdministration's(NASA) GoddardSpace

Flight Center(GSFC).Thedatawerecollectedduringthegreen-up,peak,andsenescentstagesof the

growingseasonatnumeroustowerandauxiliary sitesin boththeNorthernStudyArea(NSA)andthe

SouthernStudyArea(SSA).Thedataderivedfrom thesunphotometercoverthethreeIntensiveField

Campaigns(IFCs)in 1994:

• 31-May- 10-Jun(IFC-1)

• 21-Jul- 08-Aug(IFC-2)

• 06-Sep- 16-Sep(IFC-3)

1.3 Objective/Purpose

The objective was to acquire atmospheric optical depth data of the study sites for assessments of

spectral, spatial, and temporal variability of atmospheric aerosols and water vapor, and assessments of

the impacts of these variability's on atmospheric correction of surface reflectance and vegetation

indices. A helicopter with a pointable, stabilized mount was used to carry a spectrometer (visible and

near-infrared (NIR)), a spectroradiometer, an infrared thermometer, and a video camera. The automatic

sun-tracking photometer for helicopters (ASTPH) was deployed to provide data for calculations of

irradiance for atmospheric correction of the other sensors.

1.4 Summary of Parameters

Helicopter-based, optical depth measurements during all three IFCs in 1994 at tower and auxiliary

sites. Aerosol optical depths (ranging from 440 to 1030 nm) and atmospheric water vapor are reported.

1.5 Discussion

These measurements were collected as part of the effort to evaluate models that estimate surface

biophysical characteristics from remotely measured optical signatures.

Successful use of a helicopter-mounted sunphotometer is demonstrated. Due to the rapid response

time of the silicon detector and the associated electronics, the passage of the rotor blade is a nuisance

that can be removed during data analysis. Sufficiently accurate values of the aerosol optical thickness

are obtained in all channels. Variability in the measured voltages translates directly to variability in

derived aerosol optical thickness.

The addition of an onboard automatic sun-tracking sunphotometer system has made the helicopter

optical remote sensing system a self-contained mobile unit that can be used to acquire calibrated remote

measurements of surface parameters. Initial experience with this system shows that accurate and

reliable measurements of surface irradiance, surface reflectance, and temperature can be made in

remote areas where surface access is difficult or impractical.

1.6 Related Data Sets

BOREAS RSS-01 PARABOLA Surface Reflectance and Transmittance Data

BOREAS RSS-02

BOREAS RSS-03

BOREAS RSS-03

BOREAS RSS- 11

BOREAS RSS-12

BOREAS RSS- 12

BOREAS RSS- 19

BOREAS RSS-20

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

Reflectance Measured from a Helicopter-Mounted SE-590

Reflectance Measured from a Helicopter-Mounted Barnes MMR

Ground Network of Sun Photometer Measurements

Airborne Tracking Sunphotometer Measurements

Automated Ground Sun Photometer Measurements in the SSA

Background Spectral Reflectance Data

POLDER Measurements of Surface BRDF

Page 2
2. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. Charles L. Walthall, Physical Scientist

2.2 Title of Investigation

Biophysical Significance of Spectral Vegetation Indices in the Boreal Forest

2.3 Contact Information

Contact 1:

Dr. Charles L. Walthall

Physical Scientist

USDA Agricultural Research Service

Remote Sensing and Modeling Laboratory

Rm. 008, Bldg. 007, BARC-West

10300 Baltimore Avenue

Beltsville, MD 20705 USA

(301) 504-6074

(301) 504-5031 (fax)

cwalthal@ asrr.arsusda.gov

Contact 2:

Sara Loechel

Faculty Research Assistant

Department of Geography

University of Maryland

Remote Sensing and Modeling Laboratory

Rm. 008, Bldg. 007, BARC-West

10300 Baltimore Avenue

Beltsville, MD 20705 USA

(301) 504-6823

(301) 504-5031 (fax)

sloechel@asrr.arsusda.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

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

or diffuse), illumination incidence angle, vegetative component optical properties, and canopy

architecture. Radiation is reflected, transmitted, or absorbed.

Reflected radiation measurements were converted to radiances and reflectance factor values. The

Page 3
reflectance factor is the ratio of the target reflected radiant flux to an ideal radiant flux reflected by a

Lambertian standard surface irradiated in exactly the same way as the target. Reflected radiation from a

field reference panel corrected for nonperfect reflectance and sun angle was used as an estimate of the

ideal Lambertian standard surface (Walter-Shea and Biehl, 1990).

The BOREAS RSS-03 helicopter missions were designed to provide a rapid means of intensive

spectral characterization of sites and to provide an intermediate scale of sampling between the surface

measurements and the higher altitude aircraft and spacecraft multispectral imaging devices. The

instruments onboard the helicopter were chosen to provide compatibility with surface-based

radiometers and Thematic Mapper (TM) spaceborne sensors.

The RSS-03 helicopter-based optical depth measurements are used to perform atmospheric

corrections to radiance to obtain at-ground reflectance estimates from the helicopter-mounted

radiometers. The addition of an onboard automatic sun-tracking sunphotometer system has made the

helicopter optical remote sensing system a self-contained mobile unit that can be used to acquire

calibrated remote measurements of surface parameters. Initial experience with this system shows that

accurate and reliable measurements of surface irradiance, surface reflectance, and temperature can be

made in remote areas where surface access is difficult or impractical.

4. Equipment

4.1 Sensor/Instrument Description

The primary instruments for the BOREAS RSS-03 deployment were the SE-590, a Barnes

Modular Multiband Radiometer (MMR), a color charge-coupled device (CCD)-based video camera,

and a sun-tracking photometer.

Design, development, and fabrication of the automatic sun-tracking photometer for use with the

helicopter took place during the year prior to the 1994 BOREAS field season. This activity was

overseen by the Principal Investigator (PI). The principal design, software development, and

management were performed by Mr. Greg Elman (Science Systems and Applications, Inc. (SSAI)).

The engineering expertise of Mr. Max Strange, who had a major role in the development of the

airborne tracking sunphotometer used on the NASA C-130 fixed-wing aircraft, was an important part

of the system development. Dr. Steven Chan (SSAI), Ms. Needa Walsh (SSAI), and Mr. David

Rosten (Ressler Assoc.) contributed software expertise, optics design, and bench-testing. Mr. John

Schafer (SSAI) contributed to the system fabrication and provided hardware support in the field. Mr.

Moon Kim (Univ. of Maryland) provided software support in the field.

The automatic sun-tracking photometer consists of an optical head containing the sensors for the

eight spectral channels and a quad-detector, which is used for tracking the sun. The field of view

(FOV) on the data channels is 2 degrees, while the FOV on the quad-detector is 30 degrees. The

optical head is mounted on a motorized mount with azimuth and zenith axes. An oft-the-shelf mount

from Aerotech Corporation was used for time and cost savings. The entire optical sensor unit is

mounted on the roof of the helicopter cabin on the starboard side, directly above the primary

instrument operator. Data and control cables are fed down through a port in the helicopter cabin roof to

the rear of the center instrument rack. The length of the cables and the location of the sunphotometer

with respect to the helicopter main rotor mast create a zone of azimuthal occlusion. The usable azimuth

range is roughly 0 to 150 degrees on the starboard side of the aircraft, with 0 degrees being the

direction of the aircraft nose.

The two-axis mount controls are handled by a controller with electronics that are isolated from the

data collection system. Operator inputs for moving the mount in both the azimuthal and vertical

directions are via a joystick. Both the detector system and the mount controller system are located in

the center equipment rack. The laptop computer used for data logging is mounted on a small shelf in

the center rack.

Analog voltages from the detectors are sent to a circuit that performs the analog-to-digital (A/D)

conversion and performs the quad-detector operations for solar tracking. The digital data streams from

this device are then sent to the port of a 486-based PC laptop computer. Data logging and real-time

readout of sensor voltages are accomplished with a DOS Windows version of Labtech software. An

Page 4
LED readoutispositionedonthefrontpanelof thesensorsystemboxwith arotaryswitchfor

selectionof thedetectorchannelto bedisplayedthere.Thetemperatureof thedetectorassemblyis also

recordedwith thedetectordata.

Samplingrateconsiderationswerekey issuesin thedesignof theinstrument.A majorproblemof

mountinga sunphotometeronahelicopteris thatthesystemmustacquiredataandstaylockedonthe

solardiskwhileviewingbetweenthemovingrotorblades.Reductionof irradiancebeneathmoving

rotorbladescanbeconsiderable.A samplingrateprogrammableupto 333ks/seccanbeobtained,but

wasnotnecessarywith therotorbladefrequencyof 9 Hzfor acompleterotation(18Hz for

blade-to-bladerotation).Thesamplingof thesolarirradiancethroughthemainrotorbladeswasfast

enoughto plotthechoppingmotionof theblades.A filteringprocedurewasusedto separatethe

higher,unobstructeddatafrom thesunfrom chopper-interferedsignal.

Thebandcenterschosenfor 7 of thepossible10channelsof thesystemwere0.440,0.540,

0.613,0.670,0.870,0.940,and 1.030]am.Eachspectralbandwasapproximately0.10]amwide.

Thesebandswerechosenbecauseof theircompatibilitywiththespectralchannelsof theCimel

surface-basedsunphotometersbeingusedby otherBOREASteamsatvarioussiteswithin the

BOREASstudyareas.

Computercontrolof theinstrumentsprovidesprecise,automaticcontrolandensurespropertiming

of datacollection.Theradiometricinstrumentsareconfiguredsuchthatall sensorsexceptthe

photographiccameracanbetriggerednear-simultaneouslywith asinglecomputerkeyboardkeystroke.

Thecommandsentfrom thekeyboardis first sentto theSE-590,thento theA/D systems.Rawdata

from eachof theinstrumentsaredisplayedviagraphicsandtabularlistingsonthemaincomputer

screenimmediatelyafterscanning.

4.1.1 Collection Environment

In general,thehelicopterwasflown duringrelativelycleardayswhenpossible.Datacollection

wasattemptedduringconditionsof highestpossiblesolarelevation.All observationswereattempted

from anadirobservationpoint andusuallyat300m abovegroundlevel(AGL).Exceptionsarenoted

in thehelicopterlog.

4.1.2 Source/Platform

A Bell UH-1H "Iroquois"helicopter,operatedby NASA's WallopsFlightFacility (WFF),was

usedastheairborneplatformduringBOREAS.Thisparticularaircraft,call numberN415,wasbuilt in

1965andwasacquiredby WFF in 1993.Uponacquisition,theaircraftwasslightlymodifiedfor use

asa scientificplatform.

HelicopterN415operateswith standardor low-mount,rear-leaningskids.Theengineis a

LycomingT53/L13,whichprovides1,400shaftHPwith 1,290transmissionHP. Thefuel capacity

provides2.0hoursof flying timewith a20-minutefuelreserveundernormalmodesof operation.The

additionof anauxiliaryfueltankin theport-sidedoorcrewman'spositionprovidedanadditional15

minutesof flight timeduringBOREASgivenoptimumflight conditions.Theweightof theentire

helicoptersystemwith full instrumentation,full fuel, andcrewmemberswas9,500lbs.

4.1.3 Source/Platform Mission Objectives

One solution for atmospheric correction and calibration of remotely sensed data from airborne

platforms is the use of radiometrically calibrated instruments, sunphotometers, and an atmospheric

radiative transfer model. Sunphotometers are used to measure the direct solar irradiance at the level at

which they are operating and the data are used in the computation of atmospheric optical depth.

Atmospheric optical depth is an input to atmospheric correction algorithms that convert at-sensor

radiance to required surface properties such as reflectance and temperature. Airborne sunphotometry

has thus far seen limited use and has not been used before with a helicopter platform. The addition of

the sunphotometer to the helicopter system adds another tool for monitoring the environment and

makes the helicopter remote sensing system capable of collecting calibrated, atmospherically corrected

data independent of the need for measurements from other systems.

Although the primary motivation for development of the helicopter automatic sun-tracking

photometer was to provide data for calibration and correction of remotely sensed measurements, the

Page 5
system is also useful for the acquisition of measurements in support of atmospheric research. Optical

thickness as a function of height in the boundary layer, which an airborne sunphotometer easily

provides, is necessary to better understand vertical aerosol distributions.

4.1.4 Key Variables

Aerosol optical thickness and atmospheric water vapor.

4.1.5 Principles of Operation

Computer control of the instruments provides precise, automatic control and ensures proper timing

of data collection. The radiometric instruments are configured such that all sensors except the

photographic camera can be triggered near-simultaneously with a single computer keyboard keystroke.

The command sent from the keyboard is first sent to the SE-590, then to the A/D systems. Raw data

from each of the instruments are displayed via graphics and tabular listings on the main computer

screen immediately after scanning.

The system is configured for multiple sensor data collection. The MMR, SE-590, infrared

thermometer, auto-tracking sunphotometer, and video sensor were the primary payload during

BOREAS.

4.1.6 Sensor/Instrument Measurement Geometry

The NASA GSFC/WFF helicopter-based optical remote sensing system was deployed to acquire

canopy multispectral data simultaneously with atmospheric properties while hovering approximately

300 meters AGL (Walthall et al., 1996).

4.1.7 Manufacturer of Sensor/Instrument

The ASTPH was designed and built for the special environmental conditions of a helicopter

platform. The sunphotometer is the latest of a series of modifications to a helicopter-based optical

remote sensing system developed since 1984 by researchers at NASA's GSFC and WFF (Williams et

al., 1984; Walthall et al., 1996). Design, development, and fabrication of the ASTPH took place in

1993 prior to the field deployment for BOREAS in 1994.

4.2 Calibration

The sunphotometers used during BOREAS were calibrated before and after the field season. The

Cimel units had been extensively calibrated and were considered a source of calibration themselves.

The helicopter sunphotometer was shipped to the calibration site without the thermal control boards

operating prior to the field season. The thermal control boards were working in time for the field

deployments and for the postseason calibration. Hence, the calibration values changed. It was decided

to use data from comparisons of the voltages from the helicopter unit with nearby Cimel units as a

means of calibration.

4.2.1 Specifications

Calibration of a sunphotometer involves determining the exoatmospheric voltage response in each

of the channels. Langley plots and intercomparison methods that use the Bouguer law of atmospheric

extinction were used for those channels that did not include discrete gaseous absorption.

The raw data were first screened for voltage dropouts caused by the passage of a rotor blade. The

resulting "clear" data were then processed to obtain aerosol optical thickness. Calibration was

performed by two methods. In April 1994, the sunphotometer was taken to Mount Lemmon (elevation

9167') to perform a Langley calibration (Halthore et al., 1992) for the non-water absorption channels.

Because the instrument wiring was reconfigured after the calibration, it was felt that the Mount Lemon

calibration may not be valid for flights in the BOREAS IFCs. Thus, a special effort was made to

perform calibration by intercomparison with sunphotometers that were thought to be better calibrated.

During IFC-1 in May 1994, intercomparison was performed with the NASA Ames Research

Center sunphotometer at Candle Lake (Wrigley, R., private communication). The resulting calibration

coefficients differed from the Mount Lemmon calibrations by at most 3% and typically 2% in most

channels, thus showing that the instrument response had not been drastically altered by the

Page 6
reconfiguration.However,it wasdecidedthattheAmesintercomparisoncoefficientsfor bothIFC-1

and-2 wouldbeused.

4.2.1.1 Tolerance

Nonegiven.

4.2.2 Frequency of Calibration

None given.

4.2.3 Other Calibration Information

Because of problems with data logging during IFC-3 in September 1994, the signals from three

channels were lost (channels 2, 5, and 6). Calibration once again became a problem of utmost concern.

Intercomparison with an eight-channel sunphotometer, commonly called SXM-2, was performed at the

BOREAS SSA Operations Center near Candle Lake on a clear day (16-Sep). In the absence of a high

mountain calibration, the NASA-built SXM-2 sunphotometer, with detector temperature control and

automatic operation and data logging, was calibrated by comparison with a "standard" Cimel

sunphotometer at GSFC in October following the conclusion of IFC-3. The transferred calibration

shows deviations of less than 3% in all functioning channels. It was decided that the calibration from

IFC-3 (16-Sep) would be sufficient for analyzing data.

The fact that different calibration methods yield coefficients within about 3% indicates that the

uncertainty of the measured aerosol optical thickness will also be on the order of about 0.03; the actual

uncertainty is probably a little higher than this because of variability in the data. Considering the

conditions under which the helicopter sunphotometer operated, this level of uncertainty is acceptable.

5. Data Acquisition Methods

See Walthall et al., 1996.

The UNIDEX-11 operates in two different modes: TRACK and REGULAR. The REGULAR mode is

used to move the mount to the desired starting position (zenith and azimuth). The TRACK mode is

used when the quad detectors are commanded to take control and track the sun.

The data collection process begins by moving the mount from the HOME (azimuth angle = solar

noon, zenith angle = 0 degrees) to the desired zenith and azimuth angles as specified from operator

input. This initial input must be within 30 degrees of the sun. The PC-486 then switches the

UNIDEX- 11 into the TRACK mode and the quad-detectors take control, "locking on" the sun. The

analog output of the photodetectors is sampled for 10 cycles per ms and usually contains at least one

blade passing in the data stream. The data are acquired from the hardware, and then all data are plotted

on the operator screen. The digital raw solar irradiance data are saved to disk along with barometric

pressure and altitude data, that are used later in the data processing sequence. Analog voltages from the

seven photodetectors located in the optical head are digitized by an A/D converter.

6. Observations

6.1 Data Notes

None given.

6.2 Field Notes

An extensive helicopter log is available. Environmental, technical, instrumental, and operator

conditions are noted for each observation where applicable.

Page 7
7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The helicopter visited all of the NSA and SSA tower and category- 1 auxiliary sites. Each site listed

below was observed by the instrument at least once during the 1994 campaign at BOREAS. The

coordinates in the table are based on the North American Datum of 1983 (NAD83).

Site Id Operat'l Longitude Latitude UTM UTM UTM

Grid ID Easting Northing Zone

Flux Tower Sites

SSA:

SSA-FEN-SE501 FOL9T 104 61798 ° W 53 80206 ° N 525159 8

SSA-OBS-SE501 G814T 105 11779 ° W 53 98717 ° N 492276 5

SSA-OJP-SE501 G2L3T 104 69203 ° W 53 91634 ° N 520227 7

SSA-YJP-SE501 F8L6T 104 64529 ° W 53 87581 ° N 523320 2

SSA-9OA-SE501 C3B7T 106 19779 ° W 53 62889 ° N 420790 5

SSA-9YA-SE501 DOH4T 105 32314 ° W 53 65601 ° N 478644 1

5961566 6 13

5982100 5 13

5974257 5 13

5969762 5 13

5942899 9 13

5945298 9 13

NSA:

NSA-OBS-SE501 T3R8T

NSA-OJP-SE501 T7Q8T

NSA-YJP-SE501 T8S9T

NSA-BVP-SE501 T4U6T

NSA-FEN-SE501 T7SlT

98.48139 ° W 55 88007 ° N 532444.5

98.62396 ° W 55 92842 ° N 523496.2

98.28706 ° W 55 89575 ° N 544583.9

98.02747 ° W 55 84225 ° N 560900.6

98.42072 ° W 55 91481 ° N 536207.9

6192853.4 14

6198176.3 14

6194706.9 14

6188950.7 14

6196749.6 14

Auxiliary Sites

SSA:

SSA-9BS-SE501 DOH6S 105 29534 ° W 53 64877 ° N 480508 7

SSA-9BS-SE501 G214S 105

SSA-9BS-SE501 G2L7S 104

SSA-9BS-SE501 G6K8S 104

SSA-9BS-SE501 G914S 105

SSA-9JP-SE501 F516P 105

SSA-9JP-SE501 F7JOP 105

SSA-9JP-SE501 F7JIP 105

SSA-9JP-SE501 GIK9P 104

SSA-9JP-SE501 G4K8P 104

SSA-9JP-SE501 G7K8P 104

SSA-9JP-SE501 G8L6P 104

SSA-9JP-SE501 G9LOP 104

SSA-9JP-SE501 I218P 105

SSA-ASP-SE501 B9B7A 106

SSA-ASP-SE501 D6H4A 105

SSA-ASP-SE501 D6L9A 104

SSA-ASP-SE501 D9G4A 105

SSA-MIX-SE501 D9IIM 105

SSA-MIX-SE501 FINOM 104

SSA-MIX-SE501 G413M 105

SSA-CLR-SE501 FRSHCL 104

13964 ° W 53

63785 ° W 53

75900 ° W 53

11805 ° W 53

11175 ° W 53

05115 ° W 53

03226 ° W 53

74812 ° W 53

76401 ° W 53

77148 ° W 53

63755 ° W 53

73779 ° W 53

05107 ° W 54

18693 ° W 53

31546 ° W 53

63880 ° W 53

46929 ° W 53

20643 ° W 53

53300 ° W 53

14246 ° W 53

69194 ° W 53

93021 ° N 490831

90349 ° N 523793

94446 ° N 515847

99877 ° N 492291

86608 ° N 492651

88336 ° N 496667

88211 ° N 497879

90880 ° N 516546

91883 ° N 515499

95882 ° N 514994

96558 ° N 523778

97576 ° N 517197

11181 ° N 496661

59098 ° N 421469

70828 ° N 479177

66879 ° N 523864

74019 ° N 469047

72540 ° N 486379

80594 ° N 530753

93750 ° N 490677

91639 ° N 520205

5944263 4

5975766 3

5972844 3

5977146 9

5983169 1

5968627 1

5970323 3

5970405 6

5973404 5

5974516 6

5978963 8

5979752 7

5980856 0

5995963 1

5938447 2

5951112 1

5946733 2

5954718 4

5952989 7

5962031 8

5976354 9

5974269 4

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

Page 8
Site Id Operat'l Longitude Latitude UTM

Grid ID Zone

UTM

Easting

UTM

Northing

Auxiliary Sites

NSA:

NSA-9BS-SE501 S8W0S

NSA-9BS-SE501 TOP7S 98

NSA-9BS-SE501 TOP8S 98

NSA-9BS-SE501 TOWIS 97

NSA-9BS-SE501 T3U9S 97

NSA-9BS-SE501 T4U8S 97

NSA-9BS-SE501 T4U9S 97

NSA-9BS-SE501 T5Q7S 98

NSA-9BS-SE501 T6R5S 98

NSA-9BS-SE501 T6T6S 98

NSA-9BS-SE501 T7R9S 98

NSA-9BS-SE501 T7T3S 98

NSA-9BS-SE501 T8S4S 98

NSA-9BS-SE501 U5W5S 97

NSA-9BS-SE501 U6W5S 97

NSA-9JP-SE501 9909P 99

NSA-9JP-SE501 Q3V3P 98

NSA-9JP-SE501 T7S9P 98

NSA-9JP-SE501 TSQ9P 98

NSA-9JP-SE501 T8S9P 98

NSA-9JP-SE501 T8TIP 98

NSA-9JP-SE501 T9QSP 98

NSA- 9OA-SE501 T2Q6A 98

NSA-ASP-SE501 P7VIA 98

NSA-ASP-SE501 Q3V2A 98

NSA-ASP-SE501 R8V8A 97

NSA-ASP-SE501 S9P3A 98

NSA-ASP-SE501 T4U5A 98

NSA-ASP-SE501 T8S4A 98

NSA-ASP-SE501 V5X7A 97

NSA-ASP-SE501 WOY5A 97

NSA-MIX-SE501 QIV2M 98

NSA-MIX-SE501 TOP5M 98

NSA-BRS-SE501 BRSOL 98

NSA-TMK-SE501 TAMRK 98

NSA-BRN-SE501 BRNJP 99

97 84024 ° W 55 76824 ° N

82345 ° W 55

80225 ° W 55

80937 ° W 55

98339 ° W 55

99325 ° W 55

98364 ° W 55

64022 ° W 55

51865 ° W 55

18658 ° W 55

44877 ° W 55

22621 o W 55

37111 ° W 55

70986 ° W 55

70281 ° W 55

03952 ° W 55

02473 ° W 55

30037 o W 55

61050 ° W 55

28385 ° W 55

26269 ° W 55

59568 ° W 55

67479 ° W 55

07478 ° W 55

02635 o W 55

89260 ° W 55

87621 ° W 55

04329 ° W 55

37041 ° W 55

48565 ° W 55

33550 ° W 56

03769 ° W 55

85662 ° W 55

28889 ° W 55

42111 ° W 55

04383 ° W 55

88371 ° N

88351 ° N

78239 ° N

83083 ° N

83913 ° N

83455 ° N

91610 ° N

90802 ° N

87968 ° N

91506 ° N

89358 ° N

91689 ° N

90610 ° N

91021 ° N

88173 ° N

55712 ° N

89486 ° N

93219 ° N

90456 ° N

90539 ° N

93737 ° N

88691 ° N

50253 ° N

56227 ° N

67779 ° N

88576 ° N

84757 ° N

91856 ° N

97396 ° N

00339 ° N

54568 ° N

88911 ° N

90528 ° N

91583 ° N

88184 ° N

572761 9

511043 9

512370 1

574671 7

563679 1

563048 2

563657 5

522487 2

530092 0

550887 9

534454 5

548391 8

539306 4

580655 5

581087 8

497527 8

561517 9

543752 4

524334 5

544774 3

546096 3

525257 1

520342 0

558442 1

561407 9

569638 4

507743 3

559901 6

539348 3

594506 1

603796 6

560718 3

508967 7

544441 4

536165 1

497240 1

6180894 9

6193151 1

6193132 0

6182502 0

6187719 2

6188633 4

6188132 8

6196800 5

6195947 0

6192987 9

6196763 6

6194505 6

6197008 6

6196380 8

6196846 5

6192917 5

6157222 2

6194599 1

6198601 4

6195688 9

6195795 3

6199183 2

6193540 7

6151103 7

6157793 5

6170774 8

6193371 6

6189528 2

6197194 6

6204216 6

6207706 6

6155937 3

6193747 3

6195777 7

6196874 8

6192940 9

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

14

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

The data channels of the ASTPH view the sun with a FOV of 2 degrees, while the FOV on the

quad-detector is 30 degrees.

7.1.4 Projection

Not applicable.

Page 9
7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

Observations were made during all three BOREAS 1994 IFCs, which occurred during the

following periods:

IFC-1 24-May - 16-Jun

IFC-2 19-Jul- 10-Aug

IFC-3 30-Aug - 19-Sep

Measurements were made as conditions permitted during each IFC.

7.2.2 Temporal Coverage Map

Observations were made at several sites on the following dates:

Date Study Area

31-May-1994 SSA

01-Jun-1994 SSA

04-Jun-1994 SSA

06-Jun-1994 SSA

07-Jun-1994 SSA

08-Jun-1994 NSA

10-Jun-1994 NSA

21-Jui-1994 NSA

22-Jui-1994 SSA

23-Jui-1994 SSA

24-Jui-1994 SSA

25-Jui-1994 SSA

28-Jui-1994 SSA

04-Aug-1994 NSA

08-Aug-1994 NSA

06-Sep-1994 NSA

08-Sep-1994 NSA

09-Sep-1994 NSA

13-Sep-1994 NSA

15-Sep-1994 SSA

16-Sep-1994 SSA

7.2.3 Temporal Resolution

Measurements were collected as conditions permitted during each IFC. Each site was visited as

often as possible during each IFC, with priority given to tower flux sites and category 1 auxiliary sites.

Fuel constraints limited helicopter flight time to approximately 2 hours. As many sites as possible were

visited during each flight.

The analog output of the photodetectors is sampled for 10C ms and usually contains at least one

blade passing in the data stream. The data are acquired from the hardware every 5 milliseconds (which

yields 20 data points), and then all data are plotted on the operator screen.

Page 10
7.3 Data Characteristics

7.3.1 Parameter/Variable

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

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME OBS

OP GRID ID

NUM OBS

MEAN PRESSURE AT PLATFORM

MEAN OZONE AMOUNT

MEAN AEROSOL OPT THICK 440

MEAN AEROSOL OPT THICK 540

MEAN AEROSOL OPT THICK 610

MEAN AEROSOL OPT THICK 670

MEAN AEROSOL OPT THICK 940

MEAN AEROSOL OPT THICK 1030

MEAN COLUMN WATER VAPOR

ELEVATION

PLATFORM ALTITUDE

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:

Column Name Description

SITE NAME

SUB SITE

DATE OBS

TIME OBS

OP GRID ID

NUM OBS

MEAN PRESSURE AT PLATFORM

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 identifier given to the BOREAS auxiliary and

tower sites during the execution of field

operations. An example of this is B9B7A.

Number of observations of the given sample used

to calculate given values.

The mean atmospheric pressure measured at the

Page 11
MEAN OZONE AMOUNT

MEAN AEROSOL OPT THICK 440

MEAN AEROSOL OPT THICK 540

MEAN AEROSOL OPT THICK 610

MEAN AEROSOL OPT THICK 670

MEAN AEROSOL OPT THICK 940

MEAN AEROSOL OPT THICK 1030

MEAN COLUMN WATER VAPOR

ELEVATION

PLATFORM ALTITUDE

CRTFCN CODE

REVISION DATE

data collection platform.

The mean measured ozone amount.

The mean aerosol optical thickness measured

between 0.438 and 0.441 micrometers.

The mean aerosol optical thickness measured at

.540 micrometers.

The mean aerosol optical thickness measured

between .610 and .613 micrometers.

The mean aerosol optical thickness measured at

.670 micrometers.

The mean aerosol optical thickness measured at

.940 micrometers.

The mean aerosol optical thickness measured at

1.030 micrometers.

The mean amount of precipitable water within a

vertical column of air with a cross-section of

1 centimeter squared and a fixed depth (usually

from the ground to the top of the atmosphere).

The elevation of the site above mean sea level.

The nominal altitude of the data collection

platform above the target.

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:

Column Name Units

SITE NAME [none]

SUB SITE [none]

DATE OBS [DD-MON-YY]

TIME OBS [HHMM GMT]

OP GRID ID [none]

NUM OBS [counts]

MEAN PRESSURE AT PLATFORM [kiloPascals]

MEAN OZONE AMOUNT [Dobson]

MEAN AEROSOL OPT THICK 440 [unitless]

MEAN AEROSOL OPT THICK 540 [unitless]

MEAN AEROSOL OPT THICK 610 [unitless]

MEAN AEROSOL OPT THICK 670 [unitless]

MEAN AEROSOL OPT THICK 940 [unitless]

MEAN AEROSOL OPT THICK 1030 [unitless]

MEAN COLUMN WATER VAPOR [millimeters]

ELEVATION [meters]

PLATFORM ALTITUDE [meters]

CRTFCN CODE [none]

REVISION DATE [DD-MON-YY]

Page 12
7.3.4 Data Source

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

Column Name Data Source

SITE NAME [Assigned by BORIS]

SUB SITE [Assigned by BORIS]

DATE OBS [Controller]

TIME OBS [Controller]

OP GRID ID [Provided by RSS03 team]

NUM OBS [ASTPH]

MEAN PRESSURE AT PLATFORM [NASA Helicopter]

MEAN OZONE AMOUNT [ASTPH]

MEAN AEROSOL OPT THICK 440 [ASTPH]

MEAN AEROSOL OPT THICK 540 [ASTPH]

MEAN AEROSOL OPT THICK 610 [ASTPH]

MEAN AEROSOL OPT THICK 670 [ASTPH]

MEAN AEROSOL OPT THICK 940 [ASTPH]

MEAN AEROSOL OPT THICK 1030 [ASTPH]

MEAN COLUMN WATER VAPOR [ASTPH]

ELEVATION [Provided by RSS03 team]

PLATFORM ALTITUDE [NASA Helicopter]

CRTFCN CODE [Assigned by BORIS]

REVISION DATE [Assigned by BORIS]

7.3.5 Data Range

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

CD-ROM.

Minimum Maximum Missng Unrel Below Data

Data Data Data Data Detect Not

Column Name Value Value Value Value Limit Cllctd

SITE NAME

SUB SITE

DATE OBS

TIME OBS

OP GRID ID

NUM OBS

MEAN PRESSURE AT

PLATFORM

MEAN OZONE AMOUNT 300

MEAN AEROSOL OPT .032

THICK 440

MEAN AEROSOL OPT 0

THICK 540

MEAN AEROSOL OPT .016

THICK 610

MEAN AEROSOL OPT .029

THICK 670

MEAN AEROSOL OPT 0

THICK 940

MEAN AEROSOL OPT 0

THICK 1030

MEAN COLUMN WATER 5.24

NSA-9BS-9TETR SSA-YJP-FLXTR None None None None

RSS03-SPH01 RSS03-SPH01 None None None None

31-MAY-94 16-SEP-94 None None None None

1432 2231 None None None None

9909P WOY5A None None None None

6 173 None None None None

9.09 9.76 None None None None

370 None None None None

1.459 -999 None None None

4.215 -999 None None None

4.222 -999 None None None

4.25 -999 None None None

3.828 -999 None None None

4.056 -999 None None None

27.88 None None None None

Page 13
VAPOR

ELEVATION

PLATFORM ALTITUDE

CRTFCN CODE

REVISION DATE

175.59 650.44 None None None None

i00 300 None None None None

CPI CPI None None None None

21-NOV-98 21-NOV-98 None None None None

Minimum Data Value --

Maximum Data Value --

Missng Data Value --

Unrel Data Value --

Below Detect Limit --

Data Not Cllctd --

Blank --

N/A --

None --

The minimum value found in the column.

The maximum value found in the column.

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.

The value that indicates unreliable data. This is used

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.

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

Indicates that the value is not applicable to the respective column.

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:

SITE NAME,SUB SITE,DATE OBS,TIME OBS,OP GRID ID,NUM OBS,

MEAN PRESSURE AT PLATFORM, MEAN OZONE AMOUNT,MEAN AEROSOL OPT THICK 440,

MEAN AEROSOL OPT THICK 540,MEAN AEROSOL OPT THICK 610,MEAN AEROSOL OPT THICK 670,

MEAN AEROSOL OPT THICK 940,MEAN AEROSOL OPT THICK 1030,MEAN COLUMN WATER VAPOR,

ELEVATION, PLATFORM ALTITUDE,CRTFCN CODE,REVISION DATE

m

'SSA-ASP-AUX02', 'RSS03

.036,.048,.037,.041,11

'SSA-OJP-FLXTR', 'RSS03

.04,.061,.045,.052,12.

'SSA-YJP-FLXTR', 'RSS03

.04,.059,.043,.037,13.

'SSA-YJP-FLXTR', 'RSS03

.04,.058,.044,.035,13.

m m

-SPH01',31-MAY-94,1523, 'B9B7A',80,9.17,370.0, .068, .049,

.73,572.0,300.0, 'CPI',21-NOV-98

-SPH01',31-MAY-94,1618, 'G2L3T',I05,9.16,370.0, .084, .056,

38,579.27,300.0, 'CPI',21-NOV-98

-SPH01',31-MAY-94,1629, 'FeL6T',80,9.21,370.0, .085, .057,

66,533.24,300.0, 'CPI',21-NOV-98

-SPH01',31-MAY-94,1629, 'FeL6T',62,9.21,370.0, .076, .057,

05,533.24,300.0, 'CPI',21-NOV-98

Page 14
8. Data Organization

8.1 Data Granularity

The smallest unit of data tracked by BOREAS Information System (BORIS) is all of the

measurements for a given site on a given day.

8.2 Data Format(s)

The Compact Disk-Read-Only Memory (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

See reference list.

9.1.1 Derivation Techniques and Algorithms

See reference list.

9.2 Data Processing Sequence

9.2.1 Processing Steps

After data collection, the data set and relevant location and condition information were used to

transform the at-sensor Digital Numbers (DNs) to atmospheric optical depths and water vapor column

estimates as described in Halthore et al. (1997). In order to eliminate the rotor blade swipes, an

"unobstructed" value was calculated for each site/time. This was achieved in the optical thickness data

set by calculating the minimum value for the data collected over a given site. For the water vapor

column estimates, a median value was given. In addition, the number of observations used in

calculating the minimum or median is reported; those values calculated from a larger source data set are

more reliable.

9.2.2 Processing Changes

None.

9.3 Calculations

See reference list.

9.3.1 Special Corrections/Adjustments

None given.

9.3.2 Calculated Variables

See reference list.

9.4 Graphs and Plots

None.

Page 15
10. Errors

10.1 Sources of Error

None given.

10.2 Quality Assessment

Visual quality assessment was made during data collection. Also see reference list and helicopter

logs.

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

See helicopter logs.

10.2.5 Data Verification by Data Center

BORIS staff" performed some quality checks of the data in the process of loading the data into the

data base.

11. Notes

11.1 Limitations of the Data

None given.

11.2 Known Problems with the Data

None given.

11.3 Usage Guidance

The RSS-03 helicopter-based optical depth measurements are relevant primarily to the

helicopter-borne optical measurements, unless one is interested in the spatial distribution of

atmospheric particulates over the boreal forest.

11.4 Other Relevant Information

None.

12. Application of the Data Set

The RSS-03 helicopter-based optical depth measurements are used to perform atmospheric corrections

to radiance to obtain at-ground reflectance estimates from the helicopter-mounted radiometers.

Although the primary motivation for development of the helicopter automatic sun-tracking

photometer was to provide data for calibration and correction of remotely sensed measurements, the

system is also useful for the acquisition of measurements in support of atmospheric research. Optical

thickness as a function of height in the boundary layer, which an airborne sunphotometer easily

provides, is necessary to better understand vertical aerosol distributions.

Page 16
None.

13. Future Modifications and Plans

14. Software

14.1 Software Description

Labtech.

14.2 Software Access

Labtech software is commercially available. Software developed specifically for the ASTPH is not

available for distribution.

15. Data Access

The ASTPH 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-eosdis.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 17
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.

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

None.

17.2 Journal Articles and Study Reports

Halthore, R N., B.L. Markham, R.A. Ferrare, and T.O. Aro. 1992. Aerosol Optical Properties Over

the Midcontinental United States. Journal of Geophysical Research. 97 (D 17). Panes 18,769-18,778.

Halthore, R.N., B.L. Markham, T.F. Eck, and B.N. Holben. 1997. Sun photometric measurements

of atmospheric water vapor column abundance in the 940-nm band. Journal of Geophysical Research.

102: (D4). 4343-4352.

Holben, B.N., T.F. Eck, I. Slutsker, D. Tanre, J.P. Buis, A. Setzer, E. Vermote, J.A. Reagan, Y.J.

Kaufman, T. Nakajima, and F. Lavenu. 1996. Multi-Band Automatic Sun and Sky Scanning

Radiometer System for Measurement of Aerosols. Remote Sensing of Environment. (in press).

Lawrence, W.T., D.L. Williams, K.J. Ranson, J.R. Irons, and C.L. Walthall. 1994. Comparative

Analysis of Data Acquired by Three Narrow-Band Airborne Spectroradiometers Over Subboreal

Vegetation. Remote Sensing of Environment 47:204-215.

Loechel, S.E., C.L. Walthall, E. Brown de Colstoun, J. Chen, B.L. Markham, and J. Miller. 1997.

Variability of boreal forest reflectances as measured from a helicopter platform. Journal of Geophysical

Research, 102(D24), 29,495-29,503.

Markham, B.L., F. Wood, and S.P. Ahmad. 1988. Radiometric Calibration of the Reflective Bands

of NS001-Thematic Mapper Simulator (TMS) and Modular Multispectral Radiometers (MMR). In

Recent Advances in Sensors, Radiometry and Data Processing for Remote Sensing. Orlando. FL

Proceedings of the SPIE. 24.96-108.

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.

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1994-3.0, NASA BOREAS Report (EXPLAN 94).

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1996-2.0, NASA BOREAS Report (EXPLAN 96).

Page 18
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.BOREAS

in 1997:ExperimentOverview,ScientificResultsandFutureDirections.Journalof Geophysical

Research102(D24):28,731-28,770.

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

ReviewsChapter11,Editedby NarendraGoelandJohnNorman,Vol. 5, pp. 179-205.

Walthall, C.,S.E.Loechel,K.F. Huemmrich,E. Brown deColstoun,J.Chen,B.L. Markham,J.

Miller, andE.A. Walter-Shea.1997.SpectralInformationContentof theBorealForest.10th

InternationalColloquiumonPhysicalMeasurementsandSignaturesin RemoteSensing,International

Societyfor PhotogrammetryandRemoteSensing,Courchevel,France.

Walthall, C.L., D.L. Williams, B.L. Markham,J.E.Kalshoven,andR. Nelson.1996.

RedevelopmentandPresentConfigurationof theNASA GSFC/WFFHelicopter-BasedRemote

SensingSystem.Lincoln, NB, Proceedingsof IGARSS.

Walthall, C.L.,R.N. Halthore,G.C.Elman,J.R.Schafer,andB.L. Markham.1996.An airborne

sunphotometerfor usewith helicopters.ERIM.

Williams, D.L., C.L. Walthall, andS.N.Goward.1984.Collectionof in-situ ForestCanopySpectra

UsingaHelicopter:A Discussionof MethodologyandPreliminaryResults.Proceedingsof 1984

SymposiumonMachineProcessingof RemotelySensedData,PursueUniv., WestLafayette,IN,

94-106.

17.3 Arehive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

Page 19
19. List of Acronyms

A/D

AGL

ASCII

ASTPH

BOREAS

BORIS

CCD

CD-ROM

DAAC

DN

FOV

GIS

GSFC

HTML

IFC

MMR

NASA

NIR

NSA

OA

OBS

OJP

ORNL

PANP

RSS

SE-590

SSA

SSAI

TM

URL

UTM

WFF

YA

YJP

- Analog-to-Digital

- Above Ground Level

- American Standard Code for Information Interchange

- Automatic Sun Tracking Photometer for Helicopter

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Charge-Coupled Device

- Compact Disk-Read-Only Memory

- Distributed Active Archive Center

- Digital Number

- Field of View

- Geographic Information System

- Goddard Space Flight Center

- HyperText Markup Language

- Intensive Field Campaign

- Modular Multiband Radiometer

- National Aeronautics and Space Administration

- Near-Infrared

- Northern Study Area

- Old Aspen

- Old Black Spruce

- Old Jack Pine

- Oak Ridge National Laboratory

- Prince Albert National Park

- Remote Sensing Science

- Spectron Engineering spectroradiometer

- Southern Study Area

- Science Systems and Applications, Inc.

- Thematic Mapper

- Uniform Resource Locator

- Universal Transverse Mercator

- Wallops Flight Facility

- Young Aspen

- Young Jack Pine

20. Document Information

20.1 Document Revision Date

Written: 30-Jul- 1997

Last Updated: 18-Aug- 1999

20.2 Document Review Dates

BORIS Review: 28-Nov- 1998

Science Review:

20.3 Document ID

20.4 Citation

When using these data, please contact the individuals listed in Section 2.3 as well as citing relevant

papers in Section 17.2.

Page 20
If usingdatafromtheBOREASCD-ROM series,alsoreferencethedataas:

Walthall,C.L.,"BiophysicalSignificanceof SpectralVegetationIndicesin theBorealForest."In

CollectedDataof TheBorealEcosystem-AtmosphereStudy.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, andP. Sellers.CD-ROM. NASA, 2000.

Also,citetheBOREASCD-ROMsetas:

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, andP.Sellers,eds.CollectedDataof

TheBorealEcosystem-AtmosphereStudy.NASA. CD-ROM.NASA, 2000.

20.5 Document Curator

20.6 Document URL

Page 21
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-3 Atmospheric Measurements from a Helicopter-Mounted 923

Sunphotometer

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

C.L. Walthall, S. Loechel, and R. Halthore

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. 45

11. SUPPLEMENTARY NOTES

C.L. Walthall: U.S.D.A. Agricultural Research Service; L. Loechel: University of Maryland;

R. Halthore: Brookhaven National Laboratory; 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-3 team collected and processed helicopter-based measurements of atmospheric

conditions to estimates of aerosol optical thickness and atmospheric water vapor. The automatic suntracking photometer for helicopters was deployed during all three 1994 IFCs at numerous tower and

auxiliary sites in both the NSA and the SSA. Six spectral channels (440, 540, 613,670, 870, and 1030

nm) were chosen to span the visible and NIR wavelengths and to avoid gaseous absorption. One

additional channel, 940 nm, was selected to measure the water column abundance above the helicopter

platform. The data are stored in tabular ASCII files.

14. SUBJECT TERMS

BOREAS, remote sensing science, sun-tracking photometer.

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

21

16. PRICE CODE

20. LIMITATION OF ABSTRACT

UL

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39.18

298-102