BOREAS RSS-20 POLDER Radiance Images from the NASA C-130 Summary These data are a subset of images collected by the POLDER instrument over tower sites in the BOREAS study areas during the IFCs in 1994. The POLDER images presented here from the NASA/Ames C-130 aircraft are made available for illustration purposes only. The data are stored in binary image-format files. Note that some of the data files on the BOREAS CD-ROMs have been compressed using the Gzip program. See Section 8.2 for details. 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-20 POLDER Radiance Images from the NASA C-130 1.2 Data Set Introduction POLarization and Directionality of Earth Reflectances (POLDER) is an instrument that measures Bidirectional Reflectance Distribution Function (BRDF) and Bidirectional Polarization Distribution Function (BPDF) of terrestrial surfaces in several visible and near-infrared spectral bands. The instrument scanned several surface types (pine, spruce, fen, and others) in the BOReal Ecosystem- Atmosphere Study (BOREAS) study areas during the various Intensive Field Campaigns (IFCs) in 1994. Single-point BRDF measurements were acquired either from the National Aeronautics and Space Administration (NASA) C-130 aircraft or from a NASA helicopter. POLDER images acquired from the C-130 are made available for illustration purposes. 1.3 Objective/Purpose The objective of this investigation was to characterize the bidirectional reflectance properties of different cover types in boreal forests over several seasons (IFC-1, -2, and 3). This characterization can then be used to retrieve biophysical parameters such as Leaf Area Index (LAI), chlorophyll content, and structural canopy parameters, either through the use of semiempirical relations between reflectances and biophysical parameters or through the inversion of a BRDF radiative transfer model. The overall goal is to establish methodologies of monitoring the ecological state of the boreal forest using remote sensing techniques. 1.4 Summary of Parameters This data set contains POLDER images acquired from the C-130 at approximately 5500 m over the various tower sites. 1.5 Discussion Warning: The C-130 POLDER images are given as a qualitative information only. Although the measurements have been calibrated, no geometric correction has been applied. 1.6 Related Data Sets BOREAS RSS-01 PARABOLA Surface Reflectance and Transmittance Data BOREAS RSS-02 Level-1b ASAS Imagery: At-sensor Radiance in BSQ Format BOREAS RSS-03 Helicopter-Mounted MMR Reflectance Data BOREAS RSS-11 Airborne Tracking Sun Photometer Data BOREAS RSS-20 POLDER BRDF Measurements of Tower Flux Sites 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Marc Leroy, Dr. François-Marie Bréon, Patrice Bicheron, Olivier Hautecoeur 2.2 Title of Investigation Airborne Remote Sensing Measurements with the POLDER Instrument 2.3 Contact Information Contact 1 ------------- Dr. Marc Leroy Centre d'Etudes Spatiales de la Biosphère (CESBIO) Toulouse Cedex, France +33 5 61 55 85 14 +33 5 61 55 85 00 (fax) Marc.Leroy@cesbio.cnes.fr Contact 2 ---------------- Dr. François-Marie Bréon Laboratoire de Modélisation du climat et de l'Environnement Gif sur Yvette, France +33 1 69 08 94 55 +33 1 69 08 77 16 (fax) fmbreon@cea.fr Contact 3 -------------- Jaime Nickeson Raytheon ITSS NASA/GSFC Greenbelt, MD (301) 286-3373 (301) 286-0239 (fax) Jaime.Nickeson@gsfc.nasa.gov 3. Theory of Measurements POLDER is an optical sensor designed to observe the surface reflectance in visible and near-infrared bands. Its main characteristic is that it can observe an area from various directions. POLDER has a wide field-of-view (FOV) lens with ± 51° along-track and ± 43° cross-track viewing, and a charge-coupled device (CCD) array detector to collect images. From the NASA Ames Research Center (ARC) C-130 aircraft at an altitude of approximately 5500 m, the surface cannot be considered homogeneous. POLDER's capacity to observe an area from various view angles is used to constitute complete BRDF with the successive images acquired along different flight axes over the experimental site. 4. Equipment 4.1 Sensor/Instrument Description 4.1.1 Collection Environment It is mandatory to operate POLDER only under totally clear sky conditions, so that the distribution of irradiance does not change from one measurement to the next, and so that calculation of reflectances in absolute units from radiances is possible. 4.1.2 Source/Platform During IFC-1 and IFC-2, the POLDER instrument was installed alternatively on the C-130 aircraft, or on the helicopter. During IFC-3, the instrument flew only on the helicopter. POLDER C-130 data were acquired only in the Southern Study Area (SSA) (Prince Albert). 4.1.3 Source/Platform Mission Objectives The POLDER mission objective was to collect multiangle and multispectral bidirectional reflectance data over flux tower and auxiliary sites to study the boreal forest canopy. 4.1.4 Key Variables POLDER measures multispectral radiance in the visible and near-infrared domain as a function of Sun-view geometry. 4.1.5 Principles of Operation The POLDER optical system consists of a telecentric lens, a filter wheel, and a CCD array as a detector. The light is almost vertically incident on the filter wheel after passing the telecentric lens. The CCD array (288 x 384 elements) can collect 2-D images. The filter wheel contains 10 slots for spectral filters and polarizers. The first channel is reserved for dark current measurement, while the others allow measurements in five spectral bands (443, 550, 670, 864, and 910 nm). Two spectral bands (443 and 864 nm) are associated with three polarized filters oriented by steps of 60°. A 10-channel image, corresponding to the 10 positions of the filter wheel, is collected within 3 seconds. Each image acquisition is repeated every 10 seconds. The POLDER optical system was installed on the C-130 aircraft in the forward bay. Aircraft position and attitude parameters provided by the onboard navigation system were recorded by POLDER electronics subsystem for data postprocessing. Typical flight altitude was 5500 m. Flight lines were designed on each site to collect images in the principal, perpendicular, and 45° solar planes. 4.1.6 Sensor/Instrument Measurement Geometry The long axis of the CCD array was set parallel to the aircraft's longitudinal axis. An inclinometer was used to record the initial bias between the optical axis and true nadir. 4.1.7 Manufacturer of Sensor/Instrument The instrument was designed and manufactured by Laboratoire d'Optique Atmosphérique (LOA), USTL, 59655 Villeneuve d’Ascq Cedex, France. 4.2 Calibration Radiometric calibration data were acquired at LOA by J.-Y. Balois before and after the BOREAS experiment (11-May-1994 and 24-Oct-1994) using a calibrated integration sphere. The whole exit port of the integration sphere is used to derive the equalization coefficients (see definition in Section 9.2.1). For absolute calibration, the exit port is reduced by a diaphragm to illuminate only a small circular area in the center of the CCD array. Readings of 15 x 15 pixel window are corrected for dark current and averaged to obtain the absolute calibration coefficients (see Section 9.2.1). Other calibration experiments were made during the BOREAS experiment using a 30- inch (0.76 m) diameter portable hemisphere that is owned and operated by NASA GSFC. It was made available to the Remote Sensing Science (RSS)-20 team by Brian Markham and John Schaffer from NASA GSFC. The POLDER sensor was calibrated at the airport when POLDER was installed in the C-130 aircraft on (27-May-1994 and 21-Jul-1994). There is a good agreement between the LOA calibration and the first insitu calibration results. The second in-situ calibration shows discrepancies greater than 10% for all channels. The reasons for such discrepancies are still unknown. 4.2.1 Specifications The general specifications of calibration accuracy were 5% absolute accuracy, 3% interband relative calibration accuracy, and 2% multitemporal relative calibration accuracy. 4.2.1.1 Tolerance A general rise of the sensitivity was noted between the two calibration experiments made at LOA: 8% in the blue, 3.5% in the green and in the red, 5.5% for the 864-nm channel, and 5% for the 910-nm channel. For subsequent processing, mean coefficients obtained at LOA are used. 4.2.2 Frequency of Calibration The instrument is generally calibrated once before an experimental campaign and once after the campaign. 4.2.3 Other Calibration Information Having the spectral radiance at the outport of the sphere or the hemisphere, knowing the sensitivity of the various filters and the spectral value of the solar exoatmospheric irradiance, the normalized radiance is computed using: [Note: Equations created in MS Word do not appear in ASCII text format. Please refer to the MS Word formatted guide document.] L : spectral radiance (Wm-2sr-1µm-1) as a function of wavelength (?i) S : spectral sensitivity as a function of wavelength E : spectral exoatmospheric solar irradiance (Wm-2µm-1) as a function of wavelength The normalized radiance is used (see Section 9.2.1) to derive the absolute calibration coefficient . 5. Data Acquisition Methods For the C-130 data, the onboard navigation system gives information on the viewing geometry of each pixel. Therefore, the location and attitude data yield an approximate position of a given surface target in all POLDER images. There is a time lag of 10 seconds between each image acquisition sequence. For a typical C-130 flight altitude and speed, an angular resolution of approximately 10 degrees is obtained. 6. Observations 6.1 Data Notes None. 6.2 Field Notes None. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The POLDER images were acquired over various tower site locations. The North American Datum of 1983 (NAD83) coordinates are: West North UTM UTM UTM Site Longitude Latitude Easting Northing Zone ----- --------- -------- ------- -------- ---- SSA Fen 104.61797 53.80206 525190.7 5961344.0 13 SSA OA 106.19779 53.62890 420821.8 5942678.0 13 SSA OBS 105.11779 53.98718 492306.1 5981879.0 13 SSA OJP 104.69203 53.91634 520257.0 5974035.0 13 SSA YJP 104.64527 53.87581 523350.7 5969540.0 13 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution The pixel size is approximately 35 meters when POLDER is on the C-130. 7.1.4 Projection Each image is supplied in its original geometry with no geometric rectification or registration performed. Users will need to at least rotate the images for a coarse registration. The images are nearly centered on the tower sites. 7.1.5 Grid Description Not applicable. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage POLDER image data exist only for C-130 acquisitions taken from 26-May-1994 to 24-July-1994. Most experiments took place in the morning, except the following: 21-July: OJP (around noon), YJP, Fen.. 7.2.2 Temporal Coverage Map Images from the C-130 exist for the following dates: Site IFC-1 IFC-2 ---- ----------- ------------ Fen 07/24 OA 05/26,05/31 OBS 05/31,06/01 07/21 OJP 05/31,06/01 07/21, 07/24 YJP 06/01 07/21 7.2.3 Temporal Resolution Most sites were visited more than once in 1994. 7.3 Data Characteristics 7.3.1 Parameter/Variable Raw radiometric POLDER image data. 7.3.2 Variable Description/Definition They are essentially normalized radiances. 7.3.3 Unit of Measurement Unitless digital numbers. 7.3.4 Data Source POLDER instrument mounted on the NASA C-130 Aircraft. 7.3.5 Data Range None given. 7.4 Sample Data Record Not applicable to image data. 8. Data Organization 8.1 Data Granularity The smallest unit of data tracked by BORIS is a given image file. 8.2 Data Format(s) 8.2.1 Uncompressed Data Files The image parameter is , a digital number proportional to the observed normalized radiance for the channels without polarizers (see Section 9.2). The image data are stored in a Band Sequential (BSQ) format (9 bands, 288 lines by 384 pixels, 16 bits per pixel). Bytes Per Size Description/Name Format Pixel Npixels Nlines Nbands (Bytes) SSA-FEN_940724 Raw Binary 2 384 288 9 1990656 SSA-OA_940526 Raw Binary 2 384 288 9 1990656 SSA-OA_940531 Raw Binary 2 384 288 9 1990656 SSA-OBS_940531 Raw Binary 2 384 288 9 1990656 SSA-OBS_940601 Raw Binary 2 384 288 9 1990656 SSA-OBS_940721 Raw Binary 2 384 288 9 1990656 SSA-OJP_940531 Raw Binary 2 384 288 9 1990656 SSA-OJP_940601 Raw Binary 2 384 288 9 1990656 SSA-OJP_940721 Raw Binary 2 384 288 9 1990656 SSA-OJP_940724 Raw Binary 2 384 288 9 1990656 SSA-YJP_940601 Raw Binary 2 384 288 9 1990656 SSA-YJP_940721 Raw Binary 2 384 288 9 1990656 The table of the attitude parameters for these images follows: Mean attitude parameters Sun position Site Date Hour roll pitch heading altitude zenith azimuth ---- ---- ---- ---- ----- ------- -------- ------ ------- FEN 940724 15:49:07 0.7 3.0 191.0 5645.2 49.3 114.3 OA 940526 16:47:03 -0.1 1.8 82.4 5482.44 41.8 127.7 OA 940531 15:31:45 0.4 2.6 263.2 5457.75 51.0 107.0 OBS 940531 17:19:52 -0.3 1.6 209.8 5489.75 37.3 139.5 OBS 940601 14:49:48 0.0 2.5 349.1 5552.54 53.4 98.6 OBS 940721 17:39:30 -0.4 1.1 16.8 5493.41 36.8 147.3 OJP 940531 16:27:49 -0.3 1.9 329.0 5461.41 42.9 123.4 OJP 940601 15:44:48 -0.2 2.3 68.0 5601.0 48.4 111.7 OJP 940721 18:27:14 -0.2 2.2 198.9 5558.03 33.9 166.7 OJP 940724 16:48:45 -1.6 1.4 229.0 5595.21 42.0 131.0 YJP 940601 15:53:55 0.1 1.4 194.0 5630.57 47.1 114.1 YJP 940721 19:25:35 0.1 2.3 331.2 5567.78 33.7 191.4 8.2.2 Compressed CD-ROM Files On the BOREAS CD-ROMs, each of the 12 image files been compressed with the Gzip (GNU zip) compression program (file_name.gz). These data have been compressed using gzip version 1.2.4 and the high compression (-9) option (Copyright (C) 1992-1993 Jean-loup Gailly). Gzip uses the Lempel-Ziv algorithm (Welch, 1994) also used in the zip and PKZIP programs. The compressed files may be uncompressed using gzip (with the -d option) or gunzip. Gzip is available from many WWW sites (for example, the ftp site prep.ai.mit.edu/pub/gnu/gzip-*.*) for a variety of operating systems in both executable and source code form. Versions of the decompression software for various systems are included on the CD-ROMs. 9. Data Manipulations 9.1 Formulae See Section 9.2. 9.1.1 Derivation Techniques and Algorithms See Section 9.2. 9.2 Data Processing Sequence 9.2.1 Processing Steps 9.2.1.1 Level 1 Images The raw radiometric data are digital numbers noted , where i, j are indices of pixel location on the CCD matrix, k is the wavelength, and a is the polarizer number for spectral bands comprising three polarizers. For the other spectral bands, a is meaningless. The processing from level 0 to level 1 data consists of the transformation of raw data into data proportional to normalized radiances , according to the equation: [Note: Equations created in MS Word do not appear in ASCII text format. Please refer to the MS Word formatted guide document.] with t0 reference exposure time, used in calibration : 100 ms t exposure time during operation average of line j of dark current calibration coefficient relative sensitivity (high and low frequency) of instrumental (optics + CCD) transmission. It is normalized such that the local average of at the matrix center equals 1. sensitivity of absolute calibration to CCD temperature CCD temperature during calibration T CCD temperature in operation is a digital number proportional to the observed normalized radiance (for the channels without polarizers), i.e., with observed radiance (Wm-2sr-1µm-1) for pixel i, j in band k exoatmospheric solar irradiance in band k (Wm-2µm-1). For polarized bands, the aircraft displacement between successive channel acquisition must be taken into account to obtain a normalized spectral radiance from the three polarized channels where (x,y) are surface coordinates that refer to CCD pixels coordinates (i,j) in each of the polarized channels viewing the same ground point (x,y). The level 1 images provide data that for each band are equal to the right-hand side of the two previous equations. They are essentially normalized radiances. The following table summarizes the POLDER C-130 data acquisitions and sun and atmospheric conditions: Sun zenith angle Aerosol optical thickness Site Date degrees at 550 nm (total/below aircraft) ---- ---- ---------------- ------------------------------- Fen 24-Jul 44.4 - 49.3 0.080/0.020 03-May 38.4 - 42.8 0.130/0.055 OJP 01-Jun 48.4 - 51.4 0.095/0.050 21-Jul 33.8 - 35.0 0.120/0.095 24-Jul 40.5 - 43.3 0.095/0.020 26-May 39.4 - 41.8 0.070/0.025 01-Jun 44.0 - 47.0 0.095/0.050 YJP 21-Jul 35.5 - 37.2 0.115/0.090 31-May 35.5 - 37.4 0.135/0.070 OBS 01-Jun 53.5 - 56.4 0.060/0.030 21-Jul 33.4 - 33.7 0.115/0.090 9.2.2 Processing Changes None. 9.3 Calculations 9.3.1 Special Corrections/Adjustments Not applicable. 9.3.2 Calculated Variables Radiance, and reflectance were calculated. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error For images and BRDF data, there is some uncertainty in the absolute calibration coefficient, as illustrated by the calibration tables shown above. For the BRDF data, an additional source of error results from image registration. In the processing, it is assumed that the position of the site is the same for all images of the sequence, which can induce an error in the location of less than 1 pixel. These errors are lessened with the spatial averaging procedure. The smoothing aspect of the BRDF data tends to show that the misregistration errors are not critical. 10.2 Quality Assessment 10.2.1 Data Validation by Source The POLDER data have been tested against the 4-scale BRDF reflectance model (Leblanc et al., 1997) as well as against the PARABOLA data and the DART 3-D BRDF model (Gastellu-Etchegorry et al., 1997). 10.2.2 Confidence Level/Accuracy Judgment The uncertainty associated with POLDER spectral reflectances values, taking into account only error in the absolute calibration coefficient, is approximately less than 0.005 for the visible channels and 0.01 for the near-infrared channel. The confidence level in these measurements is good because of their reproducibility for different axes during the same flight. 10.2.3 Measurement Error for Parameters Not available. 10.2.4 Additional Quality Assessments The directional reflectances obtained with POLDER data corrected from atmospheric effects for the flux tower or auxiliary sites can be compared to similar data made by other instruments. 10.2.5 Data Verification by Data Center BORIS staff has looked at some of the POLDER imagery from the C-130. It appears that there are some registration problems between bands in some of the imagery. 11. Notes 11.1 Limitations of the Data None. 11.2 Known Problems with the Data Based on a visual review of the images by BORIS staff, it appears that there are some registration problems between bands in the imagery. 11.3 Usage Guidance Not applicable. 11.4 Other Relevant Information None. 12. Application of the Data Set Data set used for BRDF model inversion and BRDF direct models cross-check. 13. Future Modifications and Plans None. 14. Software 14.1 Software Description None given. 14.2 Software Access Raw data and processing software might be available upon request. See Section 2.3. 15. Data Access 15.1 Contact Information For BOREAS data and documentation please contact: ORNL DAAC User Services Oak Ridge National Laboratory Oak Ridge, TN 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, or fax. 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 The image data are stored on 8 mm media as BSQ raw images (9 bands, 288 lines by 384 pixels, 16 bits per pixel). 16.2 Film Products None. 16.3 Other Products None. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Welch, T.A. 1984. A Technique for High Performance Data Compression. IEEE Computer, Vol. 17, No. 6, pp. 8-19. 17.2 Journal Articles and Study Reports Bréon, F.M., V. Vanderbilt, M. Leroy, P. Bicheron, C.L. Walthall, and J.E. Kalshoven. 1997. Evidence of hot spot directional signature from airborne POLDER measurements. IEEE Transactions on Geoscience and Remote Sensing, Vol. 35, pp. 479-484. Bicheron, P., M. Leroy, O. Hautecoeur, and F.M. Bréon. 1997. Enhanced discrimination of boreal forest covers from airborne directional POLDER data. Journal of Geophysical Research, 102(D24): 29,517-29,528. Deschamps, P.Y., F.M. Bréon, M. Leroy, A. Podaire, A. Bricaud, J.C. Buriez, G. Sèze. 1994. The POLDER mission: Instrument characteristics and scientific objectives. IEEE Transactions on Geoscience and Remote Sensing, 32, pp. 598-615. Gastellu-Etchegorry J.P., P. Guillevic, F. Zagolski, V. Demarez, V. Trichon, D. Deering, and M. Leroy. 1997. Modelling BRDF and radiation regime of boreal and tropical forest. submitted to Remote Sensing of Environment. Leblanc, S.G., P. Bicheron, J.M. Chen, M. Leroy, and J. Cihlar. 1997. Investigation of directional reflectance in boreal forests with an improved 4- scale model and airborne POLDER data, IEEE Transactions on Geoscience and Remote Sensing, (submitted). Leroy, M. and F.M. Bréon. 1996. Surface reflectance angular signatures from airborne POLDER data. Remote Sensing of Environment, 57, pp. 97-107. Leroy, M., Bicheron, P., and Hautecoeur, O. 1997. An algorithm of LAI and FAPAR retrieval to be used with spaceborne POLDER/ADEOS data. In 7th International Symposium - Physical Measurements and Signatures in Remote Sensing, Courchevel, France. 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, H. Margolis, M. Ryan, J. Ranson, P.M. Crill, D.P. Lettenmeier, J. Cihlar, J. Newcomer, D. Halliwell, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin. 1997. BOREAS in 1997: Scientific results, experiment overview and future directions. Journal of Geophysical Research, 102(D24): 28,731-28,770. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None. 19. List of Acronyms 6S - Second Simulation of the Satellite signal in the Solar system ARC - Ames Research Center BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BPDF - Bidirectional Polarization Distribution Function BRDF - Bidirectional Reflectance Distribution Function BSQ - Band Sequential CCD - Change Coupled Device DAAC - Distributed Active Archive Center EOS - Earth Observing System EOSDIS - EOS Data and Information System FOV - Field-of-View GSFC - Goddard Space Flight Center IFC - Intensive field Campaign LAI - Leaf Area Index LOA - Laboratoire d'Optique Atmospherique NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NSA - Northern Study Area OA - Old Aspen OBS - Old Black Spruce OJP - Old Jack Pine ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park POLDER - POLarization and Directionality of Earth’s Reflectances RSS - Remote Sensing Science SSA - Southern Study Area URL - Uniform Resource Locator UTM - Universal Transverse Mercator YJP - Young Jack Pine 20. Document Information 20.1 Document Revision Date Written: 12-Sep-1996 Updated: 07-May-1999 20.2 Document Review Date(s) BORIS Review: 06-May-1999 Science Review: 20.3 Document ID 20.4 Citation Acknowledge Marc Leroy and Patrice Bicheron (CESBIO, Toulouse), and François- Marie Bréon (LMCE, Saclay) for providing the POLDER data. Thank LOA (Lille) for providing the POLDER instrument. Cite relevant publications (see Section 17). If using data from the BOREAS CD-ROM series, also reference the data as: Leroy, Marc, Bréon, F. M., Bicheron, P., Hautecoeur, O., "Airborne Remote Sensing Measurements with the POLDER Instrument" 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. CD-ROM. NASA, 2000. 20.5 Document Curator 20.6 Document URL Keywords: POLDER Bidirectional Reflectance Aircraft Sensors RSS20_POLDER_C130_Img.doc 06/09/99