BOREAS Level-0 TIMS Imagery: Digital Counts in BIL Format Summary For BOREAS, the TIMS imagery, along with the other remotely sensed images, was collected to provide spatially extensive information over the primary study areas. The level-0 TIMS images cover the time periods of 16-Apr-1994 to 20-Apr- 1994 and 06-Sep-1994 to 17-Sep-1994. The images are available in their original uncalibrated format. 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 Level-0 TIMS Imagery: Digital Counts in BIL Format 1.2 Data Set Introduction The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science effort covered those activities that were BOREAS community-level activities or required uniform data collection procedures across sites and time. These activities included the acquisition, processing, and archiving of 6-band Thermal Infrared Multispectral Scanner (TIMS) image data collected on the National Aeronautics and Space Administrator's (NASA's) C-130 aircraft. 1.3 Objective/Purpose For BOREAS, the TIMS imagery, along with the other remotely sensed images, was collected to provide spatially extensive information over the primary study areas. This information includes detailed land cover, biophysical parameter maps such as fraction of Photosynthetically Active Radiation (fPAR), Leaf Area Index (LAI) and surface thermal properties. 1.4 Summary of Parameters Level-0 TIMS image data in the BOREAS Information System (BORIS) contain the following parameters: original housekeeping information, calibration information, and bands 1-6 in the NASA Ames Research Center (ARC) BIL format. 1.5 Discussion BORIS staff processed the level-0 TIMS images by: 1) Extracting pertinent header information from the Level-0 image product and placing it in an American Standard Code for Information Interchange (ASCII) file on disk 2) Reading the information in the disk file and loading the online data base with needed information 1.6 Related Data Sets BOREAS Level-0 C-130 Aerial Photography BOREAS Level-0 NS001 TMS Imagery: Digital Counts in Band Interleaved by Line (BIL) Format BOREAS Level-1b TIMS Imagery: At-sensor Radiance Values in Band Sequential (BSQ) Format BOREAS Level-1b ASAS Imagery: At-sensor Radiance Values in Band Sequential (BSQ) Format 2. Investigator(s) 2.1 Investigator(s) Name and Title BOREAS Staff. 2.2 Title of Investigation BOREAS Staff Science Aircraft Data Acquisition Program. 2.3 Contact Information Contact 1 ------------------- Jeffrey S. Myers Aircraft Data and Sensor Facilities NASA Ames Research Center Moffett Field, CA (415) 604-6253 (415) 604-4987 (fax) jmyers@msmail.arc.nasa.gov Contact 2 ------------------- Jeffrey A. Newcomer NASA/GSFC Greenbelt, MD (301) 286-7858 (301) 286-0239 (fax) Jeffrey.newcomer@gsfc.nasa.gov 3. Theory of Measurements According to Planck’s equation, all objects emit radiation, depending on their temperature and emissivity. The temperature of an object is of interest in determining the radiation balance at Earth’s surface. The emissivity of an object as a function of wavelength can provide information on the object’s composition. Though much of the radiation emitted from an object is absorbed by the atmosphere, a few good atmospheric windows from 3 to 5 micrometers (um) and 8 to 14 um exist for the remote sensing of emitted surface radiation. The NASA Earth Resources Aircraft Program at ARC operates the C-130 aircraft to acquire data for Earth science research. The TIMS instrument used on the C-130 aircraft collects radiance measurements in six spectral bands covering the infrared spectrum from 8.2 to 12.2 µm. Thematic considerations have dictated, within technical constraints, the choice of spectral band position and width in the TIMS sensor. These bands were chosen after many years of analysis for their value in discrimination of geologic features, and they correspond to the emissivity anomalies associated with silicate and carbonate rocks. 4. Equipment 4.1 Sensor/Instrument Description The TIMS instrument is an optomechanical scanner designed to collect multispectral thermal imagery for geologic mapping. The TIMS is generally flown at medium altitudes and provides 3- to 20-m resolution at nadir at an altitude of 1,200 to 8,000m., respectively. The TIMS is flown aboard NASA's C-130 aircraft based at the ARC. The six spectral channels of the TIMS sensor have the following bandpasses: TIMS Channel Wavelength, um ------------- -------------- 1 8.2-8.6 2 8.6-9.0 3 9.0-9.4 4 9.4-10.2 5 10.2-11.2 6 11.2-12.2 4.1.1 Collection Environment As part of the BOREAS Staff Science Data Collection effort, BORIS distributed 6- band level-0 TIMS image data. The TIMS was flown on NASA's C-130 aircraft during the BOREAS mission (see the BOREAS Experiment Plan for flight pattern details and objectives). Maintenance and operation of the instrument are the responsibility of ARC. The C- 130 Experimenter's Handbook (supplemental) produced by the Medium Altitude Missions Branch at ARC provides a description of the instrument, calibration procedures, and data format. 4.1.2 Source/Platform NASA's C-130 Earth Resources Aircraft 4.1.3 Source/Platform Mission Objectives The original purpose of the TIMS scanner was to provide low-altitude data in the thermal infrared region of the electromagnetic spectrum for use in geologic mapping. For BOREAS, the TIMS was flown on the C-130 with a set of other scanners to provide full coverage of the reflected and emitted surface energy. 4.1.4 Key Variables Emitted radiation Reflected radiation Temperature. 4.1.5 Principles of Operation Design parameters of the TIMS are based on the specifications of Dr. Anne B. Kahle of the NASA Jet Propulsion Laboratory (JPL). A rotating scan mirror scans the instrument’s Instantaneous Field-Of-View (IFO V) across track as the motion of the aircraft moves the sensor along the data collection path. 4.1.6 Sensor/Instrument Measurement Geometry IFOV 2.5 mrad Total Scan Angle 76.56° Pixels/Scan Line 638 Sensor footprint is 10 x 10 m at nadir at 4,000 m altitude. 4.1.7 Manufacturer of Sensor/Instrument The TIMS instrument was built by Daedalus Enterprises, of Ann Arbor, Michigan. It was further modified by the NASA Stennis Space Flight Center. 4.2 Calibration General Calibration Information: After the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE), BOREAS staff attempted to further relate remotely sensed radiances to land surface radiometers. The instrument carries two onboard blackbody sources, which fill the full aperture of the system with energy of a preset, known temperature. The two blackbody sources are viewed by the TIMS once every scan line. The spectral bandpass of each channel was determined by the calibration laboratory at Stennis on an annual basis. TIMS data may be intentionally overscanned, e.g., operated at some integral multiple of the desired scan rate and then subsampled in preprocessing. The subsampling factor is reported as a "demagnification factor." 4.2.1 Specifications The wavelength ranges (in micrometers) of the bands for the TIMS are: Band Detector Wavelength Noise Equivalent Change in Temperature (NEdT) ------ -------- ------------- ------------- 1 HgCdTe 8.2-8.6 0.2°C 2 “ 8.6-9.0 0.2°C 3 “ 9.0-9.4 0.2°C 4 “ 9.4-10.2 0.2°C 5 “ 10.2-11.2 0.2°C 6 “ 11.2-12.2 0.2°C DESIGN DATA: IFOV 2.5 mrads Across-track Field-Of-View 76.56° Nominal aperture diameter 7.5 inches Effective aperture area 59.8 cm 2 f/number Not available Primary focal length Not available Inflight calibration Two controllable blackbodies V/H range Variable, 0.025 to 0.25 Scan rate Variable, 7.3 to 25 scans/sec. Scan speed ability One-third of the IFOV, scan line to scan line Data quantization 8 bits (256 discrete levels) Number of video samples/scan line 638 Roll compensation +/-15° Scan mirror 45° rotating mirror NEdt 0.25 K 4.2.1.1 Tolerance The TIMS channels were designed for noise-equivalent temperature differences for the channels, represented by the radiometric sensitivity (NEdT) of 0.25° K. 4.2.2 Frequency of Calibration The TIMS was spectrally calibrated prior to each flight season at Stennis to determine the spectral response function of each channel. 4.2.3 Other Calibration Information The TIMS instrument periodically viewed an extended-area precision blackbody source at ARC to verify linearity of response over the range of 0-50°C. 5. Data Acquisition Methods As part of the BOREAS Staff Science data collection effort, BORIS distributed 6- band level-0 TIMS image data. The TIMS was flown on NASA's C-130 aircraft during the BOREAS mission (see the BOREAS Experiment Plan for flight pattern details and objectives. Maintenance and operation of the instrument are the responsibility of ARC. The C- 130 Experimenter's Handbook (supplemental) produced by the Medium Altitude Missions Branch at ARC provides a description of the instrument, calibration procedures, and data format. 6. Observations 6.1 Data Notes Flight summary reports and verbal records on videotapes are available for the BOREAS TIMS data. 6.2 Field Notes Flight summary reports and verbal records on videotapes are available for the BOREAS TIMS data. 7. Data Description 7.1 Spatial Characteristics The BOREAS Level-0 TIMS images primarily cover the Northern Study Area (NSA) and the Southern Study Area (SSA). A few images were acquired for the transect area between the SSA and the NSA. The SSA and the NSA are located in the southwest and northeast portions of the overall region. 7.1.1 Spatial Coverage The North American Datum 183 (NAD83) corner coordinates of the SSA are: Latitude Longitude -------- --------- Northwest 54.321 N 106.228 W Northeast 54.225 N 104.237 W Southwest 53.515 N 106.321 W Southeast 53.420 N 104.368 W The NAD83 corner coordinates of the NSA are: Latitude Longitude -------- --------- Northwest 56.249 N 98.825 W Northeast 56.083 N 97.234 W Southwest 55.542 N 99.045 W Southeast 55.379 N 97.489 W 7.1.2 Spatial Coverage Map Not available. 7.1.3 Spatial Resolution Typical altitudes for BOREAS flights were 5,000 and 3,000 m above ground level (surface elevation of 400 m), which normally required 25 scan lines per second. These altitudes produced 12.5 m and 7.5 m pixels at nadir given the TIMS's 2.5 mrad IFOV. 7.1.4 Projection The BOREAS level-0 TIMS images are stored in their original data collection frame with increasing pixel sizes from nadir to the scanning extremes based on the scan angle. 7.1.5 Grid Description The BOREAS level-0 TIMS images are stored in their original data collection frame with increasing pixel sizes from nadir to the scanning extremes based on the scan angle. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The data were collected during the BOREAS Focused Field Campaign-Thaw (FFC-T) and Intensive Field Campaign (IFC)-3, covering the periods of 16 to 20-Apr-1994 and 06 to 16-Sep-1994. 7.2.2 Temporal Coverage Map IFC# Dates ----- --------------------- FFC-T 16-Apr-1994 -- 20-Apr-1994 IFC-3 06-Sep-1994 -- 17-Sep-1994 7.2.3 Temporal Resolution Images were acquired on at least one day during the field campaigns. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (tims0bil.def). 7.3.1 Parameter/Variable The main parameter contained in the image data files is: Digital Number (DN). The other parameters contained in the TIMS housekeeping are described in section 8.2. 7.3.2 Variable Description/Definition For the image data files: Digital Number (DN) - The quantized DN derived by the NS001 TMS scanning system for the respective channel. 7.3.3 Unit of Measurement For the image data files: Digital Number (DN) - counts 7.3.4 Data Source The level-0 TIMS data were collected by the TIMS instrument on the C130 aircraft. The data were processed from the aircraft tapes and supplied to BOREAS by the Medium Altitude Aircraft Branch at ARC. 7.3.5 Data Range The maximum range of DNs in each level-0 TIMS image band is limited from 0 to 255 so that the values can be stored in a single 8-bit (1-byte) field. 7.4 Sample Data Record Sample data format shown in the companion data definition file (tims0bil.def). 8. Data Organization Although the image inventory is contained on the BOREAS CD-ROM set, the actual level-0 TIMS images are not. Sample data records are shown in the companion data definition file (tims0bil.def). 8.1 Data Granularity The smallest unit of data for level-0 TIMS images is a single image. 8.2 Data Format(s) The data files contain numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe marks. There are no spaces between the fields. Sample data format shown in the companion data definition file (tims0bil.def). Each level-0 TIMS image from a given flight is contained in one file. A physical record of 4188 bytes contains 6 logical records of 698 bytes each that contain the image data (638 bytes) and housekeeping information (60 bytes) from the six TIMS spectral bands in BIL order. The bytes of the 16-bit and 32-bit values in the housekeeping information are ordered as high-order byte first. For computer systems using low-order byte first ordering, the bytes in these fields need to be swapped before they can be interpreted properly. The specific logical record structure is: Bytes Description ----------- -------------------------------------------------- Bytes 1 - 60: Housekeeping Information 1 - 2 : Status (16-bit integer) 0 implies the data are good; nonzero bad 10 Interpolated data 20 Repeated data 30 Zero fill data 3 - 4 : Filler (16-bit integer) 5 - 8 : Scan line count (32-bit integer) 9 - 12 : Thumbwheel switches (32-bit integer) Consists of 8 digits of the form DDMMYSSS where DD is day of month MM is the month Y is last digit of the year SSS is generally the mission number but could also be the sortie/flight line number 13 - 14 : Blackbody #1 Thermal Reference Temperature (16-bit integer) (hundredths of degrees C) 15 - 16 : Blackbody #2 Thermal Reference Temperature (16-bit integer) (hundredths of degrees C) 17 - 18 : Scan Speed (16-bit integer) (tenths of scans per second) 19 - 20 : Greenwich Mean Time (GMT) hours (16-bit integer) 21 - 22 : Minutes of the hour (16-bit integer) 23 - 24 : Tenths of seconds (16-bit integer) 25 - 26 : Filler (16-bit integer) (Set to 100) (Reserved for Demagnification) 27 - 28 : Filler (16-bit integer) 29 - 30 : Gain Value (times 1000) (16-bit integer) 31 - 32 : Channel Number (16-bit integer) 33 - 36 : Time (32-bit integer) (7 digits in the form of hhmmsst where hh is the hour, mm is the minute, ss is the second, and t is the tenth of a second) 37 - 38 : Blackbody #1 Response (16-bit integer) (Count) (What the sensor sees when it looks at Blackbody #1) 39 - 40 : Blackbody #2 Response (16-bit integer) (Count) (What the sensor sees when it looks at Blackbody #2) 41 - 42 : Aircraft Roll angle (16-bit integer) (tenths of degrees) (Positive values indicate clockwise rotation of the aircraft when viewed from the front; negative values indicate counterclockwise rotation) 43 - 44 : Aircraft Pitch Angle (16-bit integer) (tenths of degrees) (Positive values indicate upward movement of the front of the aircraft from a horizontal position; negative values indicate downward movement) 45 - 46 : True heading (16-bit integer) (tenths of degrees) (0 or 360 = North; 90 = East; 180 = South; 270 = West) 47 - 48 : Latitude degrees (16-bit integer) (Positive values indicate latitudes N of the Equator) 49 - 50 : Latitude tenths of minutes (16-bit integer) 51 - 52 : Longitude degrees (16-bit integer) (Positive values indicate longitudes E of the central meridian) 53 - 54 : Longitude tenths of minutes (16-bit integer) 55 - 56 : Ground speed (16-bit integer) (nautical miles per hour) 57 - 58 : Drift angle (16-bit integer) (tenths of degrees) (Positive values indicate left drift) 59 - 60 : Navigation data status bits (Bit on implies valid data) 1 bit -- Latitude 2 bit -- Longitude 4 bit -- Ground speed 8 bit -- Drift angle Bytes 61 - 698: Image data for the 638 pixels across a given scan line 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms None. 9.2 Data Processing Sequence 9.2.1 Processing Steps BORIS staff processed the level-0 TIMS images by: 1) Extracting pertinent header and calibration information from the level-0 image product and writing it to a disk file 2) Reading the information in the disk file and loading the online data base with needed information 9.2.2 Processing Changes None. 9.3 Calculations 9.3.1 Special Corrections/Adjustments The TIMS data are not geometrically corrected. The data contain both panoramic distortion, as a function of the 76.56 degree total FOV, and other spatial perturbations induced by a moving aircraft. 9.3.2 Calculated Variables None. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error See Section 9.3.1. Other sources of error include possible nonunity emissivity of the onboard blackbodies and inexact knowledge of the exact blackbody temperatures in flight conditions. 10.2 Quality Assessment 10.2.1 Data Validation by Source Spectral errors could arise because of image-wide signal-to-noise ratio, saturation, cross-talk, spikes, response normalization caused by a change in gain. 10.2.2 Confidence Level/Accuracy Judgment System optical focus is continually monitored by close observation of the apparent sharpness and resolution of objects appearing in scenes after data processing. Although this approach is somewhat subjective, it has proven to be a viable alternative compared to the classical resolution measurement method which requires removing the scanner system from the C-130 airplane with subsequent setup. This is not a practical option during the flying/deployment portion of the year. However, any observed focus degradation would be corrected by focus adjustment. 10.2.3 Measurement Error for Parameters The NEdT for the channels is typically 0.2°C. or less, depending on aircraft flight regime, with variations caused by vibration. 10.2.4 Additional Quality Assessments The TIMS has periodically viewed a precision extended-area blackbody calibration source to verify linearity over the 0-50°C. range. 10.2.5 Data Verification by Data Center The only data verification consisted of reviewing the values extracted from the tape files and loaded into the database. 11. Notes 11.1 Limitations of the Data None. 11.2 Known Problems with the Data To date, no discrepancies or problems have been noted in the data. 11.3 Usage Guidance Because of variable conditions found in different flight regimes on the C-130 aircraft, the onboard blackbody temperatures reported in the housekeeping data may be artificially high, which will result in apparently elevated ground temperatures. This is caused by cold air blasting on the front surface of these reference sources. The TIMS data are not geometrically corrected. The data contain both panoramic distortion, as a function of the 76-degree total FOV, as well as other spatial perturbations induced by a moving aircraft. 11.4 Other Relevant Information None. 12. Application of the Data Set The TIMS data can be used to analyze the thermal properties of various surface targets. 13. Future Modifications and Plans None. 14. Software 14.1 Software Description BORIS staff developed software and command procedures for: 1) Extracting header and calibration information from level-0 TIMS images on tape and writing it to ASCII files on disk 2) Reading the ASCII disk file and logging the level-0 TIMS image products into the Oracle data base tables 14.2 Software Access The software is written in C and is operational on VAX 6410 and MicroVAX 3100 systems at Goddard Space Flight Center (GSFC). The primary dependencies in the software are the tape Input/Output (I/O) library and the Oracle data base utility routines. 15. Data Access 15.1 Contact Information Ms. Beth Nelson BOREAS Data Manager NASA/GSFC Greenbelt, MD (301) 286-4005 (301) 286-0239 (fax) beth@ltpmail.gsfc.nasa.gov 15.2 Data Center Identification See Section 15.1. 15.3 Procedures for Obtaining Data Users may place requests by letter, telephone, electronic mail, or fax. 15.4 Data Center Status/Plans The level-0 TIMS image data are available from the Earth Observing System Data and Information System (EOSDIS), Oak Ridge National Laboratory (ORNL), Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 16. Output Products and Availability 16.1 Tape Products The BOREAS level-0 TIMS data can be made available on 1600- or 6250- BPI 9-track, 8-mm, or DAT tapes. 16.2 Film Products Color aerial photographs and video records were made during data collection. The video record includes aircraft crew cabin intercom conversations and an audible tone that was initiated each time the sensor was triggered. The BOREAS data base contains an inventory of available BOREAS aircraft flight documentation, such as flight logs, videotapes, and photographs. 16.3 Other Products Although the image inventory is contained on the BOREAS CD-ROM set, the actual level-0 NS001 images are not. See section 15 for information about how to obtain the data. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation There is a Daedalus Operator’s Manual for TIMS, but it is proprietary and may not be reproduced without their permission. Contact Daedalus Enterprises, Ann Arbor, MI for details. NASA. 1990. C-130 Earth Resources Aircraft Experimenter's Handbook. National Aeronautics and Space Administration, Ames Research Center. Moffett Field, California. Airborne Instrumentation Research Project. Flight Summary Reports for Flight No. 94-004-09 to 94-009-09 or April 16, 1994 to September 19, 1994. NASA Ames Research Center, Airborne Missions and Applications Division, Moffett Field. California, 94035. 17.2 Journal Articles and Study Reports 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. 1994. 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, and K. F. Huemmrich. 1994. Boreal Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC 94). 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., and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue (in press). 17.3 Archive/DBMS Usage Documentation The collected data of the BOREAS are currently archived at NASA/GSFC. 18. Glossary of Terms None. 19. List of Acronyms ARC - Ames Research Center ASCII - American Standard Code for Information Interchange BIL - Band Interleaved by Line BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BPI - Byte per inch CCRS - Canada for Remote Sensing CCT - Computer Compatible Tape CD-ROM - Compact Disk-Read-Only Memory DAAC - Distributed Active Archive Center DAT - Digital Archive Tape DN - Digital Number EOS - Earth Observing System EOSDIS - EOS Data and Information System FIFE - First ISLSCP Field Experiment FFC-T - Focused Field Campaign - Thaw FOV - Field-Of-View fPAR - fractionf of Photosynthetically Active Radiation GMT - Greenwich Mean Time GSFC - Goddard Space FLight Center HgCdTe - mercury-cadmium-tellurium IFC - Intensive Field Campaign I/O - Input/Output IFOV - Instantaneous Field-of-View ISLSCP - International Satellite Land Surface Climatology Project JPL - Jet Propulsion Laboratory LAI - Leaf Area Index NAD83 - North American Datum 1983 NASA - National Aeronautics and Space Administration NEdt - Noise-Equivalent Change in Temperature NSA - Northern Study Area ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park SSA - Southern Study Area TIMS - Thermal Infrared Multispectral Scanner TM - Thematic Mapper TMS - Thematic Mapper Simulator URL - Uniform Resource Locator 20. Document Information 20.1 Document Revision Date(s) Written: 21-Mar-1995 Last Updated: 26-Feb-1998 20.2 Document Review Date(s) BORIS Review: 06-Jan-1997 Science Review: 07-Feb-1997 20.3 Document ID 20.4 Citation The BOREAS level-0 TIMS data were collected and processed from the original aircraft tapes by personnel of the Medium Altitude Aircraft Branch at NASA ARC. Their contributions to providing this data set are greatly appreciated. 20.5 Document Curator 20.6 Document URL Keywords C130 EMITTED RADIATION THERMAL INFRARED MULTISPECTRAL SCANNER TIMS TIMS_L0.doc 04/17/98