NASA/TMm2000-209891, Vol. 47

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 47

BOREAS RSS-3 Reflectance Measured

from a Helicopter-Mounted SE-590

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

Sara Loechel, University of Maryland

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

July 2000

https://ntrs.nasa.gov/search.jsp?R=20010022166 2018-05-14T18:53:51+00:00Z
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NASA/TMm2000-209891, Vol. 47

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 47

BOREAS RSS-3 Reflectance Measured

from a Helicopter-Mounted SE-590

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

Sara Loechel, University of Maryland

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 Reflectance Measured from a Helicopter-Mounted

SE-590

Charles L. Walthall, Sara Loechel

Summary

The BOREAS RSS-3 team collected multiple remotely sensed data sets from the NASA UH-1

helicopter. This data set includes helicopter-based radiometric measurements of forested sites acquired

during BOREAS made with an SE-590 processed to reflectance factors. The data used in this analysis

were collected in 1994 during the three BOREAS IFCs at numerous tower and auxiliary sites in both

the NSA and the SSA. The 15-degree FOV of the SE-590 yielded a ground resolution of

approximately 79 m at the 300-m nominal altitude. The data are provided 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 Reflectance Measured from a Helicopter-Mounted SE-590

1.2 Data Set Introduction

Radiometer measurements of BOReal Ecosystem-Atmosphere Study (BOREAS) forested tower

and auxiliary sites were taken from a helicopter platform at nadir. The data were collected in 1994

during the green-up, peak, and senescent stages of the growing season at numerous tower and

auxiliary sites in both the Northern Study Area (NSA) and the Southern Study Area (SSA). The

15-degree field of view (FOV) of the Spectron Engineering Spectroradiometer (SE-590) yielded an

Page 1
InstantaneousFieldof View (IFOV) of approximately79m from the300m altitudetypicallyflown.

TheSE-590hasaspectralrangeof 362.7to 1122.7nm, althoughthe"usable"SE-590rangeis

actuallyN400to 900nm. TheSE-590bandwidthis N15nm andthespacingbetweenbands_3nm.

Thehelicopter-measuredSE-590radiancesandsunphotometerdatawereusedasinputtoVersion

4.0of theSecondSimulationof theSatelliteSignalin theSolarSpectrum(6S)atmosphericcorrection

softwareto obtainat-surfacereflectancefactors.ThedatacoverthethreeIntensiveFieldCampaign

(IFC) periods:31-Maythrough10-June(IFC-1),21-Julythrough08-August(IFC-2), and

06-Septemberthrough16-September(IFC-3).

1.3 Objective/Purpose

The objective of the study was to acquire multispectral, bidirectional reflectance data of the study

sites for assessments of spectral, spatial, and temporal variability and the impacts of these variabilities

on vegetation indices. A helicopter with a pointable stabilized mount was used to carry a spectrometer

(visible and near-infrared), a spectroradiometer, an infrared thermometer, and a video camera. An

autotracking sunphotometer was also deployed to provide data for calculations of irradiance and for

atmospheric correction of the data. The latest available version of the 6S atmospheric model was used

for the calculations of irradiance and for atmospheric corrections.

1.4 Summary of Parameters

Helicopter-based measurements of at-helicopter radiances and standard deviations, at-helicopter

and at-surface (atmospherically corrected) reflectances and conditions (surface physical, geometric,

and atmospheric) at the time of the observation.

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.

1.6 Related Data Sets

BOREAS RSS-01 PARABOLA SSA Surface Reflectance and Transmittance Data

BOREAS RSS-02

BOREAS RSS-03

BOREAS RSS-03

BOREAS RSS-03

BOREAS RSS- 11

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 Barnes MMR

Atmospheric Measurements from a Helicopter-Mounted Sunphotometer

Video Imagery Acquired from a Helicopter Platform

Ground Network of Sun Photometer Measurements

Automated Ground Sun Photometer Measurements in the SSA

1994 Seasonal Understory Reflectance Data

POLDER Measurements of Surface BRDF

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

Page 2
2.3 Contact Information

Contact 1:

Dr. Charles L. Walthall

Physical Scientist

USDA Agricultural Research Service

Remote Sensing and Modeling Laboratory

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

Located at:

USDA Agricultural Research Service

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.

At-sensor radiances are converted to surface reflectance using the 6S atmospheric correction

model. Using measurements of optical depth as input, this model accounts for the combined effects of

scattering (molecular and aerosol) and absorption by the atmosphere.

The 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 SE-590

instrumentation was chosen to provide compatibility with surface-based radiometers and Thematic

Mapper (TM) spaceborne sensors.

Page 3
4. Equipment

4.1 Sensor/Instrument Description

The primary instruments for the BOREAS Remote Sensing Science (RSS)-03 deployment are the

SE-590, a Barnes Modular Mnltiband Radiometer (MMR), a color Charge-Coupled Device

(CCD)-based video camera, and a sun-tracking photometer. The downward-looking sensor heads,

along with a color video camera, are mounted on an operator-controlled pointable mount that gives

variability in the view zenith and view azimuth directions independent of the heading of the aircraft.

The SE-590 is a field portable, microprocessor-controlled spectroradiometer developed in the early

1980s. The sensor is a CCD area array detector with a diffraction grating serving as the spectral

dispersion component. The complete system consists of a microprocessor-based controller connected

by cable to two optical cameras containing the sensors. Lenses are used as collimators for the optical

cameras. Although three different optical heads are available for the unit, only two can be used at once

with a single controller. The primary unit of interest is the visible/near-infrared (VIS/NIR) optical

component, which employs a silicon sensor and is sensitive to radiation in the 400 nm to 1100 nm

region. The short-wave infrared (SWIR) optical camera uses a lead sulfide detector with a cooling

device for temperature stability and is sensitive to radiation in the 1100 nm to 2500 nm spectral region.

Lenses for 1-degree and 15-degree FOV are available as standard attachments for the VIS/NIR system.

A 15 degree FOV lens for the SWIR system was specially fabricated for BOREAS. The serial number

of the instrument used was 2071.

For the BOREAS deployment, a temperature-controlled box was built to counter the effects of

ambient temperature on radiometric response of the VIS/NIR optical heads. Two VIS/NIR optical

heads were housed in the temperature control box for the final configuration, one with a 1-degree FOV

lens and one with a 15-degree FOV lens. The SWIR optical head was mounted external to the box with

a 15-degree FOV lens. The SWIR head was moved outside the temperature control box to avoid

conflicts between its temperature control system and the system of the temperature control box. The

configuration of the system was such that two of the three optical heads could be operated at once

using a single SE-590 controller. The choice of optical heads (two VIS/NIR or one VIS/NIR and the

SWIR) also required a change in software because the data stream from the SWIR optical head is

different from that of the VIS/NIR optical heads.

For helicopter use, the SE-590 is operated in a slave mode by a dedicated PC running DOS. The

data stream from the SE-590 is communicated via RS-232 cable to the computer, where it is stored on

a hard disk. The unit operates on AC power available from the aircraft via inverters with self-contained

rechargeable batteries inside the controller available for backup. Sensor integration time is set

automatically via calculations made on a spectral scan prior to each data collection scan.

The data stream from this device includes digital numbers (DNs) for each channel, sensor

dwell/integration time, date, time, and maximum signal level in DNs. The PC software adds an

operator-specified header and the SE-590 time is replaced with time from the computer's clock as the

data are stored.

4.1.1 Collection Environment

In general, the helicopter was flown during relatively clear days when possible. Data collection

was attempted during conditions of highest possible solar elevation. All observations were attempted

from a nadir observation point and usually at 300 m above ground level (AGL). Exceptions are noted

in the helicopter log.

4.1.2 Source/Platform

The UH- 1 "Huey" series of helicopters has been available as a platform for the system in many

field campaigns. The first 10 years of the system development and use were with two UH-1B Huey

helicopters, while the aircraft used for BOREAS was a UH- 1H model Huey helicopter. Wallops Flight

Facility (WFF) changed to the H-model helicopter because of its increased payload capability, the good

availability of spare parts, and its widespread use by other organizations. The Bell UH-1H "Iroquois"

helicopter, call number N415, was built in 1965 and was acquired by WFF in 1993. Upon acquisition,

the aircraft was slightly modified for use as a scientific platform.

Page 4
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.

Theinstrumentplatformcontrollers,powersuppliesanddataloggersaremountedon54-inch

wide,72-inch-highsteelrackmountsfabricatedat WFF.Threeracksaresituateddirectlyin front of

theinstrumentoperators.Seatsfor theinstrumentoperatorsarelocatedacrossthefront of the

transmissionandmainrotormasthousing.Wheneverpossible,existinghardpointsareusedfor

attachinghardwarebothinternallyandexternally.

Theweightof theentirehelicoptersystemwith full instrumentation,full fuel,andcrewmembers

was9,500lbs.

4.1.3 Source/Platform Mission Objectives

The 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 were chosen to provide compatibility with surface-based radiometers and TM spacecraft

sensors.

4.1.4 Key Variables

Surface reflectance.

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, autotracking sunphotometer, and video sensor were the primary

payload during BOREAS.

4.1.6 Sensor/Instrument Measurement Geometry

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

(GSFC)/WFF helicopter-based optical remote sensing system was deployed to acquire canopy

multispectral data with an SE-590 while hovering approximately 300 meters AGL (Walthall et al.,

1996). The 15-degree FOV of the SE-590 yielded a ground resolution of approximately 79 m at this

altitude.

4.1.7 Manufacturer of Sensor/Instrument

SE-590:

Spectron Engineering, Inc.

25 Yuma Court

Denver, CO 80223

(303) 733-1060

Page 5
4.2 Calibration

4.2.1 Specifications

Spectral Characteristics

SE-590 Range

"Usable" SE-590 Range

Bandwidth

Spacing between bands

Filter function

362.7 to 1122.7 nm

~400 to 900 nm

~15 nm

~3 nm

Gaussian (best approximation)

Spectral bands (reported in data set) [nm]:

402 6 405 3 408 0 410.7 413 4 416.1 418 8 421 5 424.2 426 9 429 6

432

462

492

523

554

586

618

650

683

716

750

784

818

852

887

3 435

4 465

9 495

7 526

9 557

5 589

5 621

9 653

6 686

7 719

2 753

0 787

3 821

9 856

9 891

0 437

2 467

7 498

5 529

8 560

4 592

4 624

8 656

6 689

7 722

2 756

1 790

4 824

0 859

1 894

8 440.5 443

9 470.7 473

5 501.3 504

4 532.2 535

7 563.5 566

3 595.2 598

4 627.3 630

8 659 8 662

6 692 6 695

8 725 8 728

3 759 4 762

2 793 3 796

5 827 7 830

2 862 4 865

3 897 5 900

2 446 0 448

4 476 2 479

1 506 9 509

0 537 9 540

4 569 3 572

1 601 0 603

2 633 2 636

7 665 7 668

6 698 6 701

8 731 9 734

4 765 5 768

4 799 5 802

8 834 0 837

6 868 7 871

7

7 451

0 481

7 512

7 543

1 575

9 606

1 639

7 671

6 704

9 738

6 771

7 805

1 840.2 843

9 875.1 878

4 454 2 456

8 484 5 487

5 515 3 518

5 546 4 549

0 577 9 580

8 609 8 612

1 642 0 645

6 674 6 677

6 707 6 710

0 741 0 744

7 774 8 777

8 808 9 812

4 846

3 881

9 459

3 490

1 520

2 552

8 583

7 615

0 647

6 680

6 713

1 747

8 780

0 815

6 849

5 884

4.2.1.1 Tolerance

None given.

4.2.2 Frequency of Calibration

Radiometric calibration and spectral calibration procedures were performed before and after the

field season to check for changes in sensor radiometric response. In-field calibration checks were

periodically made with a large, portable integrating sphere system. This sphere was used to calibrate

the airborne instruments on other aircraft and some of the surface-based radiometric instrumentation.

4.2.3 Other Calibration Information

SE-590 coefficients from the second IFC were calculated in the field. Conditions did not change

much from the beginning of the first IFC until the end of the last IFC; thus, any of the calibration files

are sufficient. The table of calibration coefficients is output from a software module that supplied

default wavelengths, instead of the exact wavelengths of this instrument. In practice, they apply to the

closest band as given in the SE-590 data set.

Page 6
Wavelength Coefficient offset of zero) and r 2 from regression

WAVE COEF r 2 WAVE COEF r 2

401 5

404 3

407 i

409 9

412 7

415 5

418 3

421 i

423 9

426 7

429 5

432 3

435 1

438 0

440 8

443 6

446 4

449 3

452 1

454 9

457 8

460 6

463 5

466 3

469 2

472 0

474 9

477 7

480 6

483 4

486 3

489 2

492 0

494 9

497 8

500 6

503 5

506 4

509 3

512 2

515 1

518 0

520 8

523 7

526 6

529 5

532 4

177 877

195 617

212 354

240 441

281 806

329 396

362 033

383 876

406 884

427 885

446 648

454 986

476 587

493 344

511 822

522 264

523 222

519 927

514 144

515 135

507 969

497 376

492 863

492 648

487 060

481 766

478 953

469 324

456 215

447 377

441 005

438 226

441 260

449 451

456 074

459 451

454 181

446 948

440 210

434 007

433 951

434 958

441 795

452 507

461 811

470 346

481 618

0 944291

0 953270

0 959176

0 969660

0 976171

0 983505

0 985738

0 987624

0 989234

0 990205

0 991536

0 992297

0 994173

0 994685

0 995202

0 995745

0 996257

0 996496

0 997100

0 997069

0 997500

0 997683

0 997825

0 997897

0 998084

0 998269

0 998335

0 998460

0 998530

0 998650

0 998666

0 998647

0 998873

0 998914

0 998928

0 999010

0 999101

0 999090

0 999098

0 999064

0 999189

0 999175

0 999182

0 999234

0 999292

0 999288

0 999324

535 3

538 3

541 2

544 1

547 0

549 9

552 8

555 8

558 7

561 6

564 5

567 5

570 4

573 3

576 3

579 2

582 2

585 1

588 1

591 0

594 0

596 9

599 9

602 9

605 8

608 8

611 8

614 7

617 7

620 7

623 7

626 7

629 6

632 6

635 6

638 6

641 6

644 6

647 6

650 6

653 6

656 6

659 6

662 6

665 7

668 7

671 7

485 763

486 522

487 035

481 228

471 868

464 951

456 612

454 872

459 347

467 344

478 390

489 023

496 558

505 392

507 749

504 828

498 284

489 910

480 059

470 787

463 137

457 157

454 545

455 709

458 806

463 753

469 958

477 498

482 404

482 992

480 767

477 871

473 047

464 294

456 748

448 964

442 057

436 108

433 334

426 841

424 231

418 953

417 769

419 553

418 793

418 464

418 540

0 999395

0 999378

0 999372

0 999428

0 999408

0 999458

0 999396

0 999417

0 999432

0 999438

0 999478

0 999479

0 999513

0 999555

0 999551

0 999536

0 999541

0 999553

0 999562

0 999550

0 999574

0 999541

0 999552

0 999546

0 999567

0 999581

0 999595

0 999620

0 999643

0 999660

0 999653

0 999653

0 999663

0 999626

0 999657

0 999647

0 999641

0 999634

0 999650

0 999646

0 999654

0 999628

0 999646

0 999671

0 999664

0 999665

0 999691

Page 7
WAVE COEF r 2 WAVE COEF r 2

674 7

677 7

680 8

683 8

686 8

689 9

692 9

695 9

699 0

702 0

705 1

708 1

711 2

714 2

717 3

720 4

723 4

726 5

729 6

732 6

735 7

738 8

741 8

744 9

748 0

751 1

754 2

757 3

760 4

763 5

766 6

769 7

772 8

775 9

779 0

782 1

785 2

419 266

414 472

408 282

402 339

394 407

383 948

377 904

371 917

366 746

362 821

364 155

361 576

364 754

370 359

372 134

376 i00

381 964

383 358

385 283

387 747

389 354

385 004

379 187

371 829

363 352

354 343

347 139

340 538

336 410

329 992

325 867

319 102

311 361

305 954

299 664

296 534

292 414

0 999675

0 999683

0 999666

0 999697

0 999663

0 999669

0 999662

0 999645

0 999641

0 999658

0 999659

0 999668

0 999664

0 999676

0 999673

0 999686

0 999712

0 999717

0 999733

0 999745

0 999746

0 999735

0 999740

0 999722

0 999721

0 999710

0 999680

0 999703

0 999688

0 999674

0 999690

0 999647

0 999645

0 999653

0 999634

0 999644

0 999615

788 3

791 4

794 5

797 7

800 8

803 9

807 1

810 2

813 3

816 5

819 6

822 7

825 9

829 0

832 2

835 3

838 5

841 6

844 8

848 0

851 1

854 3

857 5

860 6

863 8

867 0

870 2

873 4

876 5

879 7

882 9

886 1

889 3

892 5

895 7

898 9

902 1

288 519

287 586

286 344

284 828

282 668

279 686

277 144

275 932

271 085

266 655

262 913

257 784

250 574

244 616

237 477

228 120

219 124

211 521

204 434

195 746

189 681

187 142

185 715

183 007

181 422

180 540

176 893

171 383

167 060

163 815

160 072

156 389

154 292

151 666

147 559

143 946

138 765

0 999602

0 999618

0 999597

0 999584

0 999593

0 999592

0 999604

0 999587

0 999558

0 999554

0 999582

0 999555

0 999536

0 999500

0 999479

0 999470

0 999430

0 999392

0 999410

0 999362

0 999332

0 999297

0 999299

0 999294

0 999319

0 999299

0 999283

0 999210

0 999245

0 999196

0 999179

0 999145

0 999143

0 999141

0 999065

0 999039

0 998934

Page 8
5. Data Acquisition Methods

The use of off-the-shelf field instruments aboard airborne platforms is a cost-effective and efficient

approach to assembling a data collection system. The instruments are generally rugged enough for the

harsh operating environment of a helicopter, provide data comparable to data sets on the surface, and

are easy to use and versatile during operation. The system developed jointly at NASA GSFC and WFF

uses several widely accepted field-portable radiometric instruments. The system is configured such that

instruments from other investigators can be deployed on the helicopter with little or no interference

with the primary instrument system. An autotracking sunphotometer system, developed specifically for

use on helicopters, is the newest addition to the system.

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

canopy multispectral data with an SE-590 while hovering approximately 300 meters AGL (Walthall et

al., 1996). The 15-degree FOV of the SE-590 yielded an IFOV at this altitude of approximately 79 m.

Observations were made over various tower and auxiliary sites during all three IFCs.

Measurements were collected as conditions permitted during each IFC. In general, the helicopter

would hover 1-2 minutes for each observation (consisting of an average number of 20-25 scans).

6. Observations

6.1 Data Notes

See Section 6.2.

6.2 Field Notes

An extensive helicopter log is available for each IFC. Environmental, technical, instrumental, and

operational conditions are noted for each observation where applicable.

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 this instrument at least once during the 1994 campaign at BOREAS. The

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

UTM UTM UTM

Site Id Grid Id Longitude Latitude Easting Northing Zone

Flux Tower Sites

Southern Study Area:

SSA-FEN-MMR01 FOL9T 104

SSA-OBS-MMR01 G814T 105

SSA-OJP-MMR01 G2L3T 104

SSA-YJP-MMR01 F8L6T 104

SSA-9OA-MMR01 C3B7T 106

SSA-9YA-MMR01 DOH4T 105

61798 ° W 53

11779 ° W 53

69203 ° W 53

64529 ° W 53

19779 ° W 53

32314 ° W 53

80206 ° N 525159.8 5961566

98717 ° N 492276.5 5982100

91634 ° N 520227.7 5974257

87581 ° N 523320.2 5969762

62889 ° N 420790.5 5942899

65601 ° N 478644.1 5945298

6 13

5 13

5 13

5 13

9 13

9 13

Page 9
UTM UTM

Northinc Zone Site Id Grid Id Longitude Latitude

UTM

Easting

Flux Tower Sites

Northern Study Area:

NSA-OBS-MMR01 T3R8T 98 48139 ° W 55 88007 ° N

NSA-OJP-MMR01 T7Q8T 98 62396 ° W 55 92842 ° N

NSA-YJP-MMR01 T8S9T 98 28706 ° W 55 89575 ° N

NSA-BVP-MMR01 T4U6T 98 02747 ° W 55 84225 ° N

NSA-FEN-MMR01 T7SlT 98 42072 ° W 55 91481 ° N

532444.5

523496.2

544583.9

560900.6

536207.9

6192853 4

6198176 3

6194706 9

6188950 7

6196749 6

14

14

14

14

14

Auxiliary Sites

Southern Study Area:

SSA-9BS-MMR01 DOH6S

SSA-9BS-MMR01 G214S 105

SSA-9BS-MMR01 G2L7S 104

SSA-9BS-MMR01 G6K8S 104

SSA-9BS-MMR01 G914S 105

SSA-9JP-MMR01 F516P 105

SSA-9JP-MMR01 F7JOP 105

SSA-9JP-MMR01 F7JIP 105

SSA-9JP-MMR01 GIK9P 104

SSA-9JP-MMR01 G4K8P 104

SSA-9JP-MMR01 G7K8P 104

SSA-9JP-MMR01 G8L6P 104

SSA-9JP-MMR01 G9LOP 104

SSA-9JP-MMR01 I218P 105

SSA-ASP-MMR01 B9B7A 106

SSA-ASP-MMR01 D6H4A 105

SSA-ASP-MMR01 D6L9A 104

SSA-ASP-MMR01 D9G4A 105

SSA-MIX-MMR01 D9IIM 105

SSA-MIX-MMR01 FINOM 104

SSA-MIX-MMR01 G413M 105

105 29534 ° W 53 64877 ° N

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

93021 ° N

90349 ° N

94446 ° N

99877 ° N

86608 ° N

88336 ° N

88211 ° N

9O88O ° N

91883 ° N

95882 ° N

96558 ° N

97576 ° N

11181 ° N

18693 ° W 53.59098 ° N

31546 ° W 53.70828 ° N

63880 ° W 53.66879 ° N

46929 ° W 53.74019 ° N

20643 ° W 53.72540 ° N

53300 ° W 53.80594 ° N

14246 ° W 53.93750 ° N

480508 7

490831 4

523793 6

515847 9

492291 2

492651 3

496667 0

497879 4

516546 7

515499 1

514994 2

523778 0

517197 7

496661 4

421469 8

479177 5

523864 0

469047 1

486379 7

530753 7

490677 3

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

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

13

Page 10
UTM UTM

Site Id Northinc Zone Grid Id Longitude Latitude

UTM

Easting

Auxiliary Sites

Northern Study Area:

NSA-9BS-MMR01 S8W0S

NSA-9BS-MMR01 TOP7S 98

NSA-9BS-MMR01 TOP8S 98

NSA-9BS-MMR01 TOWIS 97

NSA-9BS-MMR01 T3U9S 97

NSA-9BS-MMR01 T4U8S 97

NSA-9BS-MMR01 T4U9S 97

NSA-9BS-MMR01 T5Q7S 98

NSA-9BS-MMR01 T6R5S 98

NSA-9BS-MMR01 T6T6S 98

NSA-9BS-MMR01 T7R9S 98

NSA-9BS-MMR01 T7T3S 98

NSA-9BS-MMR01 T8S4S 98

NSA-9BS-MMR01 U5W5S 97

NSA-9BS-MMR01 U6W5S 97

NSA-9JP-MMR01 9909P 99

NSA-9JP-MMR01 Q3V3P 98

NSA-9JP-MMR01 T7S9P 98

NSA-9JP-MMR01 TSQ9P 98

NSA-9JP-MMR01 T8S9P 98

NSA-9JP-MMR01 T8TIP 98

NSA-9JP-MMR01 T9QSP 98

NSA-9OA-MMR01 T2Q6A 98

NSA-ASP-MMR01 P7VIA 98

NSA-ASP-MMR01 Q3V2A 98

NSA-ASP-MMR01 R8V8A 97

NSA-ASP-MMR01 S9P3A 98

NSA-ASP-MMR01 T4U5A 98

NSA-ASP-MMR01 T8S4A 98

NSA-ASP-MMR01 V5X7A 97

NSA-ASP-MMR01 WOY5A 97

NSA-MIX-MMR01 QIV2M 98

NSA-MIX-MMR01 TOP5M 98

97 84024 ° W 55.76824 ° N

82345 ° W 55.88371 ° N

80225 ° W 55.88351 ° N

80937 ° W 55.78239 ° N

98339 ° W 55 83083 ° N

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

83913 ° N

83455 ° N

91610 ° N

90802 ° N

87968 ° N

91506 ° N

89358 ° N

91689 ° N

90610 ° N

91021 ° N

88173 ° N

02473 ° W 55.55712 ° N

30037 ° W 55 89486 ° N

61050 ° W 55

28385 ° W 55

26269 ° W 55

59568 ° W 55

67479 ° W 55

93219 ° N

90456 ° N

90539 ° N

93737 ° N

88691 ° N

07478 ° W 55.50253 ° N

02635 ° W 55.56227 ° N

89260 ° W 55 67779 ° N

87621 ° W 55

04329 ° W 55

37041 ° W 55

48565 ° W 55

33550 ° W 56

88576 ° N

84757 ° N

91856 ° N

97396 ° N

00339 ° N

03769 ° W 55.54568 ° N

85662 ° W 55.88911 ° 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

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

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 15-degree FOV of the SE-590 yielded a ground resolution of 79 m from the 300 m altitude.

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

Page 11
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-June

• IFC-2 19-July- 10-August

• IFC-3 30-August- 19-September

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. In general, the helicopter

would hover 1-2 minutes for each observation (consisting of an average number of 20-25 scans). Each

site was visited as often as possible during each IFC, with priority given to tower flux sites and

category 1 auxiliary sites. Helicopter flight time was limited to approximately 2 hours by fuel

constraints. As many sites as possible were visited during each flight.

7.3 Data Characteristics

Page 12
7.3.1 Parameter/Variable

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

Reference File

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME

OP GRID INFO

PLATFORM ALTITUDE

ELEVATION

SOLAR ZEN ANG

SOLAR AZ ANG

SUN PHOTO SOURCE

SUN PHOTO TIME

INTERP AEROSOL OPT THICK 550

COLUMN WATER VAPOR

COVER TYPE

HELO LOG TRIP ID

CRTFCN CODE

REVISION DATE

Data File

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME

WAVELENGTH

MEAN RADIANCE

SDEV RADIANCE

MEAN REFL

MEAN SURF REFL

GASEOUS TRANSMITTANCE

CRTFCN CODE

REVISION DATE

Page 13
7.3.2 Variable Description/Definition

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

Reference File

Column Name Description

SITE NAME

SUB SITE

DATE OBS

TIME

OP GRID INFO

PLATFORM ALTITUDE

ELEVATION

SOLAR ZEN ANG

SOLAR AZ ANG

SUN PHOTO SOURCE

SUN PHOTO TIME

INTERP AEROSOL OPT THICK 550

COLUMN WATER VAPOR

COVER TYPE

HELO LOG TRIP ID

CRTFCN CODE

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 site identifier used by this RSS team during

the execution of field operations. This is used

to further link data to site information

contained elsewhere..

The nominal altitude of the data collection

platform above the target.

The elevation of the site above mean sea level.

The angle from the surface normal (straight up)

to the sun during data collection.

Direction referred to as a circular scale of

degrees read clockwise describing the position of

the sun where 0=north, 90=east, 180=south, and

270:west.

Indicator of the source of the sun photometer

measurements used in atmospheric correction,

where helo=helicopter sunphotometer, NSA-YJP =

NSA-YJP tower site, Thom : Thompson airport

(NSA), SSA-YJP : SSA-YJP tower site.

The time of the sun photometer measurement used

in atmospheric correction.

The aerosol optical depth interpolated to 550

nanometers, used in the atmospheric correction.

The 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 dominant species, vegetation or type of land

cover that exists at the location.

Identifier, given as Mon-Day-(A/B/C), whose

letter identifies the particular flight on a

given day, used in the helo log file.

The BOREAS certification level of the data.

Page 14
REVISION DATE

Data File

Column Name

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.

Description

SITE NAME

SUB SITE

DATE OBS

TIME

WAVELENGTH

MEAN RADIANCE

SDEV RADIANCE

MEAN REFL

MEAN SURF REFL

GASEOUS TRANSMITTANCE

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.

Spectral wavelength at which measurement was

acquired.

The mean at-sensor radiance.

The standard deviation at-sensor radiance.

The mean reflectance factor.

The mean surface reflectance factor

(atmospherically corrected).

One minus the absorptance and reflectance of the

atmosphere (two-way) due to global gases

(primarily water vapor and ozone).

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.

The OP_GRID_INFO in the SE590 reference data are tightly linked to the Helicopter log

documentation; much information relevant to the location of the observation and the conditions at the

time are available in the log.

Page 15
7.3.3 Unit of Measurement

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

Reference File

Column Name Units

SITE NAME [none]

SUB SITE [none]

DATE OBS [DD-MON-YY]

TIME [HHMMSS GMT]

OP GRID INFO [none]

PLATFORM ALTITUDE [meters]

ELEVATION [meters]

SOLAR ZEN ANG [degrees]

SOLAR AZ ANG [degrees]

SUN PHOTO SOURCE [none]

SUN PHOTO TIME [HHMMSS GMT]

INTERP AEROSOL OPT THICK 550 [unitless]

COLUMN WATER VAPOR [millimeters]

COVER TYPE [none]

HELO LOG TRIP ID [none]

CRTFCN CODE [none]

REVISION DATE [DD-MON-YY]

Data File

Column Name Units

SITE NAME

SUB SITE

DATE OBS

TIME

WAVELENGTH

MEAN RADIANCE

SDEV RADIANCE

MEAN REFL

MEAN SURF REFL

GASEOUS TRANSMITTANCE

CRTFCN CODE

REVISION DATE

[none]

[none]

[DD-MON-YY]

[HHMMSS GMT]

[micrometers]

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

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

[percent]

[percent]

[unitless]

[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:

Reference File

Column Name Data Source

SITE NAME

SUB SITE

DATE OBS

TIME

OP GRID INFO

PLATFORM ALTITUDE

ELEVATION

SOLAR ZEN ANG

[Assigned by BORIS Staff]

[Assigned by BORIS Staff]

[Controller]

[Controller]

[RSS03 team]

[NASA Helicopter]

[Experiment Plan]

[Calculated by software]

Page 16
SOLAR AZ ANG

SUN PHOTO SOURCE

SUN PHOTO TIME

INTERP AEROSOL OPT THICK 550

COLUMN WATER VAPOR

COVER TYPE

HELO LOG TRIP ID

CRTFCN CODE

REVISION DATE

Data File

Column Name

[Calculated by software]

[RSS03 team]

[Helo or RSSll sunphotometer]

[Helo or RSSll sunphotometer]

[Calculated by software]

[Experiment Plan]

[RSS03 team]

[Assigned by BORIS Staff]

[Assigned by BORIS Staff]

Data Source

SITE NAME

SUB SITE

DATE OBS

TIME

WAVELENGTH

MEAN RADIANCE

SDEV RADIANCE

MEAN REFL

MEAN SURF REFL

GASEOUS TRANSMITTANCE

CRTFCN CODE

REVISION DATE

[Assigned by BORIS Staff]

[Assigned by BORIS Staff]

[Controller]

[Controller]

[SE-590 spectroradiometer]

[SE-590 spectroradiometer]

[Calculated by software]

[Calculated by software]

[Calculated by software]

[Calculated by software]

[Assigned by BORIS Staff]

[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.

Reference File

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

OP GRID INFO

PLATFORM ALTITUDE

ELEVATION

SOLAR ZEN ANG

SOLAR AZ ANG

SUN PHOTO SOURCE

SUN PHOTO TIME

INTERP AEROSOL OPT

THICK 550

COLUMN WATER VAPOR

COVER TYPE

HELO LOG TRIP ID

CRTFCN CODE

REVISION DATE

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

RSS03-SE501 RSS03-SE501 None None None

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

143212 225100 None None None

N/A N/A None None None

304.8 304.8 None None None

136 650.44 None None None

32.827 63.215 None None None

96.059 253.65 None None None

Helo Thom None None None

143300 223200 None None None

.0315 .7464 None None None

6.35 27.01 None None None

N/A N/A None None None

531A 916B None None None

CPI CPI None None None

13-JUN-98 13-JUN-98 None None None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

None

Page 17
Data File

Column Name

Minimum Maximum Missng Unrel Below Data

Data Data Data Data Detect Not

Value Value Value Value Limit Cllctd

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

SUB SITE RSS03-SE501 RSS03-SE501 None None None None

DATE OBS 31-MAY-94 16-SEP-94 None None None None

TIME 143212 225100 None None None None

WAVELENGTH .4026 .9007 None None None None

MEAN RADIANCE 1.5 112.11 None None None None

SDEV RADIANCE .034 i0.011 None None None None

MEAN REFL .4 44.9 None None None None

MEAN SURF REFL 0 49.3 -999 None None None

GASEOUS .77 1 None None None None

TRANSMITTANCE

CRTFCN CODE CPI CPI None None None None

REVISION DATE 02-JUN-98 05-JUN-98 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

to indicate an attempt was made to determine the

parameter value, but the value was deemed to be

unreliable by the analysis personnel.

Below Detect Limit -- 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.

Data Not Cllctd -- 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.

Page 18
7.4 Sample Data Record

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

Reference File

SITE NAME,SUB SITE,DATE OBS,TIME,OP GRID INFO,PLATFORM ALTITUDE,ELEVATION,

SOLAR ZEN ANG, SOLAR AZ ANG, SUN PHOTO SOURCE,SUN PHOTO TIME,

INTERP AEROSOL OPT THICK 550,COLUMN WATER VAPOR, COVER TYPE,HELO LOG TRIP ID,

CRTFCN CODE,REVISION DATE

'SSA-9OA-FLXTR', 'RSS03-SE501',31-MAY-94,151500, 'C3B7T',304.8,600.63,53.01,

i03.522, 'Helo',152300, .0584,11.73, 'A', '531A', 'CPI',I3-JUN-98

'SSA-ASP-AUX02', 'RSS03-SE501',31-MAY-94,152309, 'B9B7A',304.8,572.0,51.83,

105.375 , 'Helo',152300, .0584,11.73, 'A', '531A', 'CPI',I3-JUN-98

'SSA-OJP-FLXTR', 'RSS03-SE501',31-MAY-94,161810, 'G2L3T',304.8,579.27,43.681,

121.2 01, 'Helo',161500, .073,12.375, 'JP', '531A', 'CPI',I3-JUN-98

Data File

SITE NAME, SUB SITE, DATE

MEAN REFL,MEAN SURF REFL,GASEOUS

'SSA-ASP-AUX05', 'RSS03-SE501', 13-SEP-94,201824

02-JUN-98

'SSA-ASP-AUX05', 'RSS03-SE501', 13-SEP-94,201824

02-JUN-98

'SSA-ASP-AUX05', 'RSS03-SE501', 13-SEP-94,201824

02-JUN-98

TRANSMITTANCE CRTFCN CODE

.4026,2.82,

OBS,TIHE,WAVELENGTH,HEAN RADIANCE,SDEV RADIANCE,

REVISION DATE

073,1.0, .6,1.0, 'CPI',

.4053,3.09, 07,1.0, .7,1.0, 'CPI',

.408,3.2, .07,1.0, .7,1.0, 'CPI',

8. Data Organization

8.1 Data Granularity

The smallest amount of data that can be ordered from this data set is a day's worth of data for a

given site.

8.2 Data Format

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.

Page 19
9. Data Manipulations

9.1 Formulae

9.1.1 Derivation Techniques and Algorithms

From Vermote et al. (1997):

"Two atmospheric processes modify the solar radiance reflected by a target when viewed from space:

absorption by the gases (when observation bands are overlapping gaseous absorption bands) and

scattering by the aerosols and the molecules. If the gaseous absorption can be de-coupled from

scattering as if the absorbents were located above the scattering layers, as assumed in the 6S code, the

equation of transfer for a Lambertian homogeneous target of reflectance P_SFC at sea level altitude

viewed by a satellite sensor (under zenith angle of view theta v and azimuth angle of view phi_v) and

illuminated by sun (theta_s, phi_s) is...:

P_TOA(thetas, theta v, phi_s-phi_v) = T_g(theta_s, theta v) * [P_R+A + T dn(theta_s) *

T_up(theta_v) * {P_SFC / (1 - S*P_SFC)}]. (1)

The various quantities are expressed in terms of equivalent reflectance P defined as P = pi * L/mu_s*

E_s where L is the measured radiance, E_s is the solar flux at the top of the atmosphere, and mu_s =

cos(theta_s) where theta_s is the solar zenith angle."

In addition, note the following notation (Vermote et al, 1997):

T_g Gaseous transmission of water vapor, carbon dioxide,

oxygen, and ozone.

P TOA Reflectance at the top of the atmosphere.

P R+A Intrinsic reflectance of the molecule+aerosol layer.

T dn Total transmission of the atmosphere on the path

between the sun and the surface.

T_up Total transmission of the atmosphere on the path

between the surface and the sensor.

S Spherical albedo of the atmosphere.

9.2 Data Processing Sequence

9.2.1 Processing Steps

The SE-590 sensor voltages were processed to at-sensor radiances (W/m2 sr mm) following

procedures described in Markham et al. (1988). Calibration coefficients were obtained before and after

the deployment at NASA GSFC and onsite during the deployment using a portable calibration

apparatus. The individual data scans were examined and those with obvious spurious values (i.e.,

outliers in the distribution) were removed.

The mean helicopter SE-590 radiances and sunphotometer data from either the helicopter or the

nearest RSS-11 ground sunphotometer were then input into Version 4.0 of the 6S software (Vermote

et al., 1997) to obtain at-surface reflectance factors corrected for atmospheric effects. There was close

agreement between the helicopter-mounted sunphotometer and nearby RSS-11 measurements.

9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

None.

Page 20
9.3.2 Calculated Variables

See Section 9.1.1.

9.4 Graphs and Plots

Not included here. See Loechel et al., 1996.

10. Errors

10.1 Sources of Error

Potential sources of error include radiometric calibration; spectral calibration; physical

(environmental and human) conditions (including helicopter vibration, minor changes in helicopter

altitude and inclination); atmospheric conditions, including atmospheric parameters estimated from the

surface sunphotometer network; and the atmospheric correction algorithm (Vermote et al., 1997).

Confidence intervals for the visible/near-infrared at-sensor radiance values presented in this data set are

within 3%. The possibility of errors being introduced into the data set increases with additional

manipulations of the data. For an in-depth discussion of error considerations, see Markham et al.

(1988).

10.2 Quality Assessment

Visual quality assessment was performed during data collection. See reference list and helicopter

logs.

10.2.1 Data Validation by Source

None given.

10.2.2 Confidence Level/Accuracy Judgment

A thorough quantitative error analysis of this kind of data set is given in Markham et al. (1988).

10.2.3 Measurement Error for Parameters

Confidence intervals for the at-sensor radiance values presented in this data set are within 3%.

10.2.4 Additional Quality Assessments

See helicopter logs. Also, see reference: Walthall et al., 1997.

10.2.5 Data Verification by Data Center

A visual examination of all of the helicopter-mounted SE-590 at-surface reflectances reveals

artifacts from the atmosphere in all of the spectra. This is especially obvious in the oxygen and water

absorption regions in the near-infrared. That all the atmospheric effects have not been removed from

the near-infrared bands causes one to suspect the atmospheric corrections in the visible bands as well.

While the atmospheric effects on at-surface reflectance at any given wavelength may be small,

these effects may cause significant problems in some types of hyperspectral analyses. Some analysis

techniques look at band-to-band covariances or derivatives. The atmospheric effects are nonlinear with

wavelength, and thus, by not completely removing these effects, the data become questionable for

those types of analyses.

Page 21
11. Notes

11.1 Limitations of the Data

See Section 10.2.5.

11.2 Known Problems with the Data

Caution should be used when using a band reflectance in the near-infrared calculated with a

gaseous transmittance much under 0.9; i.e., use caution in the oxygen band (N760 nm) and the water

vapor absorption band (N820 nm) -- where absorption effects can be under/overestimated,

respectively. It is suggested that a neighboring band not affected by gaseous absorption be used,

which seems to characterize surface absorption effects well through the near-infrared.

Data collected over sparse canopies and with extreme solar geometry (i.e., early morning/late

afternoon observations) will contain substantial amounts of shadow, which may complicate the

retrieval of surface vegetation parameters.

In addition, isolated atmospheric events (such as forest fires or scattered cloudiness) reduce the

certainty in the atmospheric correction. The use of surface-measured atmospheric variables contributes

to error in the data set in those cases.

11.3 Usage Guidance

See Sections 10.2.5, 11.1, and 11.2.

11.4 Other Relevant Information

None given.

12. Application of the Data Set

Research questions that may be examined with this data include:

• Retrieval of leaf area index (LAI) from spectral vegetation index.

• Scaling of spectral response in boreal regions (in combination with other BOREAS data sets).

None.

13. Future Modifications and Plans

14. Software

14.1 Software Description

The software used in the atmospheric correction of this data set was 6S, Version 3.2 (Vermote et

al., 1997).

14.2 Software Access

This software is public domain and available via anonymous ftp at kratmos.gsfc.nasa.gov.

Page 22
15. Data Access

The RSS-03 reflectance 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/[Internet Link].

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.

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.

Page 23
17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Markham, B.L., D.L. Williams, J.R. Schafer, F. Wood, and M.S. Kiln. 1995. Radiometric

characterization of diode-array field spectroradiometers. Remote Sensing of Environment, vol. 51, pp.

317-330.

17.2 Journal Articles and Study Reports

Loechel, S., C.L. Walthall, E. Brown de Colstoun, J. Chen, and B. Markham. 1996. Spatial and

temporal variability of surface cover at BOREAS using reflectance from a helicopter platform.

International Geosciences and Remote Sensing Symposium (IGARSS), Lincoln, NE.

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.M. Wood Jr., 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 Proc. SPIE 24, pp.

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).

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994

Operations. NASA BOREAS Report (OPS DOC 94).

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996

Operations. NASA BOREAS Report (OPS DOC 96).

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

Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal

ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year.

Bulletin of the American Meteorological Society. 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, and F.E. Guertin. 1997. BOREAS

in 1997: Experiment Overview, Scientific Results and Future Directions. Journal of Geophysical

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

Strebel, D.E., D.R. Landis, K.F. Huemmrich, and W.W. Meeson. 1994. Collected Data of The First

ISLSCP Field Experiment, Volume 1: Surface Observations and Non-Image Data Sets. Published on

CD-ROM by NASA.

Vermote, E., D. Tanre, and J. Morcrette. 1997. Second simulation of the satellite signal in the solar

spectrum, 6S: an overview. IEEE Trans. Geosci. Remote Sens., vol. 35, no. 3, pp. 675.

Page 24
Vermote,E., D. Tanre,J.L.Deuze,M. Herman,andJ.J.Morcrette.1996.Secondsimulationof the

satellitesignalin thesolarspectrum(6S),6SUserGuideVersion1,October7, 1996.Universityof

Maryland/Laboratoired'OptiqueAtmospherique,216pp.(availablevia anonymousftp at

kratmos.gsfc.nasa.gov).

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

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

Walthall,C. andE.Middleton.1992.Assessingspatialandseasonalvariationsin grasslandswith

spectralreflectancesfrom ahelicopterplatform.J.Geophys.Res.,97(D17):18,905-18,912.

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

presentconfigurationof theNASA GSFC/WFFhelicopter-basedremotesensingsystem.International

GeosciencesandRemoteSensingSymposium(IGARSS).Lincoln,NE.

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.

17.3 Arehive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

6S

AGL

ASCII

BOREAS

BORIS

BSQ

CCD

CD-ROM

DAAC

DN

EOS

EOSDIS

FOV

GIS

GSFC

HTML

IFC

IFOV

LAI

MMR

NAD83

NASA

NSA

19. List of Acronyms

- Second Simulation of the Satellite Signal in the Solar

- Above Ground Level

- American Standard Code for Information Interchange

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Band Sequential

- Charge-Coupled Device

- Compact Disk-Read-Only Memory

- Distributed Active Archive Center

- Digital Number

- Earth Observing System

- EOS Data and Information System

- Field of View

- Geographic Information System

- Goddard Space Flight Center

- Hyper-Text Markup Language

- Intensive Field Campaign

- Instantaneous Field of View

- Leaf Area Index

- Modular Multiband Radiometer

- North American Datum of 1983

- National Aeronautics and Space Administration

- Northern Study Area

Spectrum

Page 25
ORNL - Oak Ridge National Laboratory

PANP - Prince Albert National Park

RSS - Remote Sensing Science

SE-590 - Spectron Engineering spectroradiometer

SSA - Southern Study Area

SWIR - Short-Wave Infrared

TM - Thematic Mapper

URL - Uniform Resource Locator

UTM - Universal Transverse Mercator

VIS/NIR - Visible/Near-Infrared

WFF - Wallops Flight Facility

20. Document Information

20.1 Document Revision Date

Written: 31-Oct- 1995

Last Updated: 30-Jul- 1999

20.2 Document Review Date(s)

BORIS Review: 30-Nov- 1997

Science Review: 30-Sep- 1998

20.3 Document ID

20.4 Citation

If this data set is referenced by another investigator, please acknowledge the RSS-03 investigation

team and this document. When using these data, please include the following acknowledgement as

well as citations of relevant papers in Section 17.2:

The efforts of Dr. Charles Walthall (USDA BARC) and Sara Loechel (University of Maryland) in

collecting these data and making them available as well as the efforts of BORIS staff in processing the

data are greatly appreciated.

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

Walthall, C. and S. Loechel, "Biophysical Significance of Spectral Vegetation Indices in the Boreal

Forest." 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 26
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

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

BOREAS RSS-3 Reflectance Measured from a Helicopter-Mounted SE-590

6. AUTHOR(S)

Charles L. Walthall and Sara Loechel

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

5. FUNDING NUMBERS

923

RTOP: 923-462-33-01

8. PEFORMING ORGANIZATION

REPORT NUMBER

2000-03136-0

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

TM--2000-209891

Vol. 47

11. SUPPLEMENTARY NOTES

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

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 multiple remotely sensed data sets from the NASA UH-1

helicopter. This data set includes helicopter-based radiometric measurements of forested sites acquired during BOREAS made with an SE-590 processed to reflectance factors. The data used in this

analysis were collected in 1994 during the three BOREAS IFCs at numerous tower and auxiliary

sites in both the NSA and the SSA. The 15-degree FOV of the SE-590 yielded a ground resolution of

approximately 79 m at the 300-m nominal altitude. The data are provided in tabular ASCII files.

14. SUBJECT TERMS

BOREAS, remote sensing science, SE-590.

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Unclassified

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Unclassified

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