BOREAS RSS-14 Level-2 GOES-7 Shortwave and Longwave Radiation Images Summary The BOREAS RSS-14 team collected and processed several GOES-7 and GOES-8 image data sets that covered the BOREAS study region. This data set contains images of shortwave and longwave radiation at the surface and top of the atmosphere derived from collected GOES-7 data. The data cover the time period of 05-Feb- 1994 to 20-Sep-1994. The images missing from the temporal series were zero- filled to create a consistent sequence of files. The data are stored in binary image format files. Note that the level-2 GOES-7 data are not contained on the BOREAS CD-ROM set. An inventory listing file is supplied on the CD-ROM to inform users of the data that were collected. See Sections 15 and 16 for information about how to acquire the data. 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-14 Level-2 GOES-7 Shortwave and Longwave Radiation Images 1.2 Data Set Introduction For the BOReal Ecosystem-Atmosphere Study (BOREAS), the level-2 Geostationary Operational Environmental Satellite 7 (GOES-7) imagery, along with the other remotely sensed images, were collected in order to provide spatially extensive information over the primary study areas at varying spatial scales. These level-2 GOES-7 shortwave and longwave (SW/LW) images acquired and processed by Dr. Eric Smith serve to define the surface radiation budget (SRB) for the BOREAS region. 1.3 Objective/Purpose The primary objectives are 1) to retrieve the SRB from the level-1 GOES-7 visible images over the BOREAS region at a high temporal and spatial resolution, and 2) to quantify the uncertainties of satellite-derived SRB products. 1.4 Summary of Parameters The level-2 GOES-7 SW/LW product contains the following parameters: *Narrow-band albedo at TOA (0.5 to 0.7 µm) [0.1 %] Column water vapor amount [0.01 cm] *SW down at TOA (0.3 to 3.0 µm) [0.1 W/m2] *Narrow-band albedo at TOA (0.5 to 0.7 µm) [0.1 %] Narrow-band cloud albedo (0.5 to 0.7 µm) [0.1 %] Narrow-band minimum albedo (0.5 to 0.7 µm) [0.1 %] SW down at surface (0.3 to 3.0 µm) [0.1 W/m2] SW up at surface (0.3 to 3.0 µm) [0.1 W/m2] Surface SW albedo (0.3 to 3.0 µm) [0.1 %] *PAR down (0.4 to 0.7 µm) [0.1 W/m2] *PAR up (0.4 to 0.7 µm) [0.1 W/m2] *PAR albedo (0.4 to 0.7 µm) [0.1 %] Net LW at surface (4.0 to 100.0 µm) [0.1 W/m2] * where TOA is the top of the atmosphere, and PAR is photosynthetically active radiation. 1.5 Discussion Dr. Eric Smith, from Florida State University (FSU), provided the BOREAS Information System (BORIS) with the level-1 GOES-7 images that were used to create the level-2 products. 1.6 Related Data Sets BOREAS RSS-14 Level-1 GOES-7 Visible, Infrared, and Water-Vapor Images BOREAS RSS-14 Level-3 Gridded Radiometer and Satellite Surface Radiation Images BOREAS RSS-14 Level-1 GOES-8 Visible, Infrared, and Water-Vapor Images BOREAS RSS-14 Level-1a GOES-8 Visible, Infrared, and Water-Vapor Images 2. Investigator(s) 2.1 Investigator(s) Name and Title Dr. Eric A. Smith, Professor 2.2 Title of Investigation Surface Radiation Budget Retrieved from GOES-7 VISSR Imagery for Large Scale BOREAS Area 2.3 Contact Information Contact 1 --------- Ms. Jiujing Gu Florida State University Tallahassee, FL (904) 644-7511 (904) 644-9639 (fax) jgu@huey.met.fsu.edu Contact 2 --------- Dr. Eric A. Smith Florida State University Tallahassee, FL (904) 644-4253 (904) 644-9639 (fax) esmith@metsat.met.fsu.edu Contact 3 --------- Jaime Nickeson Raytheon ITSS NASA GSFC Greenbelt, MD (301) 286-7858 (301) 286-0239 (fax) Jaime.Nickeson@gsfc.nasa.gov 3. Theory of Measurements The GOES mission is to provide the nearly continuous, repetitive observations that are needed to predict, detect, and track severe weather. GOES spacecraft are equipped to observe and measure cloud cover, surface conditions, snow and ice cover, surface temperatures, and the vertical distributions of atmospheric temperature and humidity. They are also instrumented to measure solar X-rays and other energetics, collect and relay environmental data from platforms, and broadcast instrument data and environmental information products to ground stations. The GOES system includes the satellite (with the GOES instrumentation and direct downlink data transmission capability); the National Environmental Satellite, Data and Information Service (NESDIS) facility at Wallops Island, VA; and the ground systems at NESDIS. 4. Equipment 4.1 Sensor/Instrument Description The original GOES instrument was the Visible and Infrared Spin Scan Radiometer (VISSR), which was an outgrowth of the spin-scan radiometer flown aboard several of the Applications Technology Satellite (ATS) series of National Aeronautics and Space Administration (NASA) research satellites. The VISSR was first flown aboard Synchronous Meteorological Satellites (SMS)-1 and -2 used by the National Oceanic and Atmospheric Administration (NOAA). GOES-1, -2, and -3 were operational satellites that flew the original VISSR instrument. GOES-4 through -7 were flown with a modified instrument package called the VISSR Atmospheric Sounder (VAS). A set of infrared sensors was added to provide an atmospheric sounder capability. The VAS instrument system is an expansion of the VISSR system with improved structural design and some additional capabilities. It consists of the same type of scanning system, a telescope with lighter weight optics made from beryllium instead of conventional materials (glass, steel), eight visible detectors (25 x 24 microradian Instantaneous Field of View (IFOV)), and six infrared detectors. 4.1.1 Collection Environment The data were acquired using the FSU Direct Readout Ground System located in Tallahassee, FL, starting on 01-Jan-1994 and continuing through July 1995. The GOES-7 satellite orbited Earth in a geostationary orbit at an altitude of 42,000 km. 4.1.2 Source/Platform Launch and data-available dates for the GOES-7 satellite are: Satellite Launch Date Data Range --------- ----------- ----------------------- GOES-7 26-Feb-1987 25-Mar-1987 to mid-1995 4.1.3 Source/Platform Mission Objectives See Sections 1.3 and 3. 4.1.4 Key Variables The key variables in this data set are: -- surface downward solar and PAR flux -- surface broad-band and narrow-band albedo -- surface net LW flux 4.1.5 Principles of Operation The VISSR instrument consists of a scanning system, telescope, and infrared and visible sensors. The scanning system consists of a mirror that is stepped mechanically to provide north to south viewing, while the 100-rpm rotation of the GOES satellite provides west to east scanning. The mirror is stepped following each west to east scan. The mirror position is controlled by one of two optical encode wheels attached to the axis. Each step of the mirror causes a change of 192 µrad in the scan angle, representing a distance of 6.9 km near nadir. A sequence of 1,821 scans over 18.21 minutes is performed to provide a "full disk" view from just beyond the northern Earth horizon to just beyond the southern Earth horizon. The scanning mirror reflects the received radiation into a 16-inch-diameter telescope. A fiber-optics bundle is used to couple the telescope to eight visible detectors (sensitive to the 0.54 to 0.70 micrometer band). The fiber optics bundle is configured such that each of the eight visible sensors has a 20 (W-E) by 25 (N-S) microradian (µrad) FOV on GOES-7. The sensors are arranged in a linear array oriented "north-south" (i.e., perpendicular to the scan direction) thus sweeping out eight parallel scan line paths as the satellite rotates. The FOV provides a ground resolution of 0.9 km (normally referred to as 1 km or 0.5 nautical miles). The system thus provides eight parallel 1 visible data lines per west to east scan, covering the 6.9-km (normally referred to as 8-km or 4-mile) band scanned by each step of the scanning mirror. In addition, germanium relay lenses are used to pass received radiation to two HgCdTe infrared detectors by way of a 10.5 to 12.6 micrometer bandpass filter. The FOV of the infrared detectors is 192 µrad (equal to the north-south scan step angle), and thus the infrared sensors provide equivalent coverage to the eight visible sensors. The output from the eight visible detectors and from one of the two infrared detectors (or an average of both infrared detectors) is digitized onboard the satellite and transmitted down to Earth in real time. The visible data are sampled every 2 microseconds, which yields visible samples spaced at increments of satellite rotation of 20.9 µrad (assuming a nominal satellite spin rate of 100 rpm), or a near-nadir spacing of 3.0 km. Since the infrared detector FOV is 192 microradians, the infrared data are therefore oversampled in the scan direction. The quantization of the infrared data is 8 bits, and of the visible data 6 bits. The visible scanners are digitized with a square root digitizer for better signal-to-noise ratio. The oversampling of the infrared data leads to their designation as "4 by 2" infrared data (4-mile resolution north-south, 2-mile resolution west-east). The full-resolution scan of all sensors in the mode produces about 226 Mbytes of data per image. 4.1.6 Sensor/Instrument Measurement Geometry When the VISSR/VAS is installed in the spacecraft, its optical axis becomes parallel to the spacecraft spin axis, which must be parallel to Earth's spin axis. The VAS optical axis is thus perpendicular to the direction of the Earth scene. The optically flat scan mirror of the VAS, placed at a 45-degree angle to the VAS optical axis, directs the Earth scene into the VAS. The spinning is accomplished by stepping the scan mirror from 40 degrees, representing the north polar extreme, to 50 degrees, representing the south polar extreme. An angle position encoder integral with the mirror stepping mechanism converts the position information to electrical signals, which are sent to the Command and Data Acquisition (CDA) station to aid in reassembly of the Earth scene. The 10 degrees of mirror motion (resulting in 20 degrees of optical angle after doubling the optical angle at the mirror) is divided into 1,821 steps, each representing 192 µrad optically. At the image plane, a relatively large FOV is available. Each detector element is dimensional to define the FOV its signal is intended to represent. For example, the smallest infrared field is 192 µrad defined by a square detector 0.00315 inches on each side. (At synchronous altitude, 192 µrad is equivalent to 5 miles along Earth's surface at the satellite's suborbital point.) Two focal planes are used in the VAS. Visible spectrum signals are obtained at the principal focus. An optical fiber for each of the eight FOVs defines the field to be measured (25 by 24 microradian) and conveys the impinging light within that FOV to a photomultiplier tube (PMT), which converts the light intensity to a proportional electrical current. Infrared radiation must be sensed by solid state detectors, which are cooled to a low temperature to reduce their intrinsic electrical noise to a level below the electrical equivalent of the least intense radiation to be measured. This cooling is provided by a radiation cooler that radiates excess heat into space. Because of spacecraft design constraints, the cooler must be located away from the prime focal plane. The relay optics provide an appropriate location for an infrared focusing mechanism and filter assembly out of the visible light path. The filter assembly contains a 11.2-centimeter disc, called a filter wheel, that houses 12 spectral pass band filters. During each scan, one filter is placed in the infrared path to acquire data in the desired spectral band. Any one of the filters can be positioned in the infrared optical FOV within 350 milliseconds (i.e., during the time that the VAS telescope is not viewing Earth during a given spin). Filters are inserted in the infrared path only and used in the Multispectral Imaging (MSI) and sounding modes. While 38 channels are possible with the filter wheel detector combinations, only 13 bands can be transmitted. The scanning schedule and the various modes of operation are uploaded to an electronics module in the satellite. The satellite includes an onboard controller that can itself be reprogrammed via the spacecraft command link. 4.1.7 Manufacturer of Sensor/Instrument Hughes Santa Barbara Remote Sensing (SBRS) Goleta, CA 4.2 Calibration The visible channels are calibrated in a vacuum environment at five instrument temperature plateaus. Some adjustments are made to standardize the bit content and start time of the stretched data scans. Preflight Calibration a. Visible Channel Calibration: The visible channel calibration source is a quartz iodine lamp, the output of which is collimated and spectrally shaped using appropriate optical filters similar to the sun over the spectral band of the visible channels. The output level of the calibration source is established by eight neutral density filters that provide a calibration range from 16% to 100% albedo. The absolute calibration accuracy of the visible channels is estimated to be +/- 10%. b. Thermal Channel Calibration: The visible thermal channels are calibrated at eight target scene temperatures between 180 and 315 K, using a temperature- controlled blackbody source. The estimated absolute calibration accuracy is +/- 1.5 °C, or +/- 1% of full scale, whichever is larger. In-flight Calibration a. Visible Channels: In-flight calibration of the eight visible PMTs is accomplished by viewing the sun through the complete visible channel optical train via a "side-looking," reduced-aperture collecting prism. The visible channel gains are adjusted in the ground station processing to equalize the eight scanners. This is done to remove stripping of the images. Other gain adjustments are occasionally made for image clarity. Absolute calibrations with the sun viewer are not part of the GOES operating procedure. However, some research programs have produced limited calibrations for parts of the GOES data record. b. Thermal Channel: The in-flight calibration of the visible thermal channel is accomplished by monitoring the temperature of a black-body. This blackbody is activated by command and introduced into the optical path just ahead of the infrared relay optical system. The space view by visible provides an approximately zero signal reference in the thermal bands that is used to establish the zero-end of the measurement scale. 4.2.1 Specifications IFOV Visible 25 x 24 microradians Infrared 192 x 192 microradians RESOLUTION (subsatellite) Visible 0.9 km Infrared 6.9 km ALTITUDE 35,600 km GOES SPIN RATE 100 rpm SCAN RATE 1821 scans/min SCAN RANGE approx. 60°N to 60°S SAMPLES/SCAN 3,822 infrared and 15,288 visible samples per PMT detector per Earth scan ORBIT POSITION: 0.0°N, 75.0°W 4.2.1.1 Tolerance None given. 4.2.2 Frequency of Calibration Calibration of the visible and infrared channels is performed after every scan using internal calibrators that are part of the VAS VISSR instrumentation. However, routine calibrations are not made on the visible sensor. 4.2.3 Other Calibration Information It has been reported by Rossow et al. (1995) that the sensitivities of the VISSR instruments deteriorate at a rate of about 10% per year, and with some short- term variabilities. To account for these sensitivity changes, we have applied the calibration coefficients from International Satellite Cloud Climatology Project (ISCCP) to the GOES-7 visible imagery to convert visible counts to TOA radiances. The ISCCP calibration is available for every month during most of the 1994 Intensive Field Campaigns (IFCs) and Field Focused Campaigns (FFCs). Further information about ISCCP calibration can be found at http://isccp.giss.nasa.gov/calib.html. 5. Data Acquisition Methods The BOREAS level-2 SW/LW images were created from level-1 GOES-7 visible images. The imagery was obtained by Dr. Eric Smith at FSU and supplied to BORIS. The data were acquired using the FSU Direct Readout Ground System located in Tallahassee, FL, starting on 01-Jan-1994 and continuing through December 1995. 6. Observations 6.1 Data Notes None given. 6.2 Field Notes Not applicable. 7. Data Description 7.1 Spatial Characteristics 7.1.1 Spatial Coverage The scanning system consists of a mirror that is stepped mechanically to provide north to south viewing, while the rotation of the GOES satellite provides west to east scanning. The mirror is stepped following each west to east scan. A sequence of 1,821 scans over 18.21 minutes is performed to provide a "full disk" view from just beyond the northern Earth horizon to just beyond the southern Earth horizon. Based on the level-1 GOES-7 images, the level-2 SW/LW product covers the entire 1,000-km by 1,000-km BOREAS region. This contains the Southern Study Area (SSA), the Northern Study Area (NSA), the transect region between the SSA and NSA, and some surrounding area. Based on information contained in the reference latitude and longitude files for the visible band (see Section 8.2), the following North American Datum of 1983 (NAD83) coordinates represent the nominal coverage of the level-2 SW/LW product: Latitude Longitude ---------- ----------- Northwest 64.757 N 107.037 W Northeast 65.911 N 87.120 W Southwest 47.646 N 109.210 W Southeast 47.916 N 98.087 W The NAD83 corner coordinates of the BOREAS region are: Latitude Longitude ---------- ----------- Northwest 59.97907 N 111.00000 W Northeast 58.84379 N 93.50224 W Southwest 51.00000 N 111.00000 W Southeast 50.08913 N 96.96951 W 7.1.2 Spatial Coverage Map Not available at this time. 7.1.3 Spatial Resolution The GOES-7 SW/LW images have a nominal pixel resolution of 8 x 8 km (approximately 14.2 x 6.6 km at BOREAS latitudes). For details, see Kelly, 1989. 7.1.4 Projection The BOREAS level-2 SW/LW data are stored in the same GOES 'perfect' projection as the level-1 images. The 'perfect' projection indicates that the satellite movement between temporal acquisitions has been removed so the images are aligned spatially. Detailed information about the projection is not currently available. 7.1.5 Grid Description Not available at this revision. 7.2 Temporal Characteristics 7.2.1 Temporal Coverage The SW images provide continuous coverage for the period of 05-Feb to 20-Sep- 1994. The LW images cover only the snow-free period from 23-May to 20-Sep-1994. 7.2.2 Temporal Coverage Map The times when images were acquired varied over the year. The following table gives the times when data are available: Dates Times --------------- ----------------- 05-Feb - 14-Feb 16:00 - 21:00 UTC 15-Feb - 14-Mar 15:30 - 22:00 UTC 14-Mar - 11-Apr 14:00 - 23:30 UTC 12-Apr - 02-May 13:00 - 00:30 UTC 03-May - 08-Aug 13:00 - 01:30 UTC 09-Aug - 28-Aug 13:00 - 00:30 UTC 29-Aug - 20-Sep 14:00 - 00:30 UTC 7.2.3 Temporal Resolution The images were acquired every 30 minutes during the specified time periods of each day. 7.3 Data Characteristics Data characteristics are defined in the companion data definition file (goes72.def). 7.4 Sample Data Record Sample data format shown in the companion data definition file (goes72.def). 8. Data Organization 8.1 Data Granularity The smallest unit of data for the level-2 GOES-7 SW/LW imagery is a series of SW or LW images for a given day. 8.2 Data Format(s) The data file contain 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. Sample data records are shown in the companion data definition file (goes72.def). A complete day of SW and LW data is contained in several SW files and one LW file. The storage format/arrangement of the data is due to the manner in which the SW and LW components were derived and delivered by FSU. Each SW file contains all the SW parameter images for one 30-minute period. The SW file contains 49 records of 8192 bytes. Each SW parameter image contains 128 2-byte pixel values in each of the 128 lines and is stored in four data file records (i.e., 128 * 2 * 128 = 32,768 and 32,768/4 = 8,192). The series of records in the SW file is: Record Number Content Storage format ------------- -------------------------- --------------------------- 01 Header Record (128 ASCII Characters/Line) 02-05 Scaled Visible Reflectance (16 bit integers) 06-09 Scaled Water Vapor (16 bit integers) 10-13 Scaled TOA Down (16 bit integers) 14-17 Scaled NB TOA Albedo (16 bit integers) 18-21 Scaled NB Cloud Albedo (16 bit integers) 22-25 Scaled NB Minimum Albedo (16 bit integers) 26-29 Scaled SW Down (16 bit integers) 30-33 Scaled SW Up (16 bit integers) 34-37 Scaled Surface Albedo (16 bit integers) 38-41 Scaled PAR Down (16 bit integers) 42-45 Scaled PAR Up (16 bit integers) 46-49 Scaled PAR Albedo (16 bit integers) Each LW file contains all the LW parameter images delivered for a given day. The LW files contain 105 records of 8,192 bytes each (105 * 8,192 = 860,160 bytes per file), one record (8,192 bytes) for the header, and four records for each of 26 images, equaling a total of 104 records of image data. Each LW parameter image contains 128 2-byte pixel values in each of the 128 lines, stored in four 8,192-byte records (128 samples * 2 bytes * 128 lines = 32,768 bytes, and 32,768/4 = 8192). The series of records in the LW file are: Record Number Content Storage format ------------- -------------------------- --------------------------- 01 Header Record (128 ASCII Characters/Line) 002-005 Image for 1300 UTC (16 bit integers) 006-009 Image for 1330 UTC (16 bit integers) 010-013 Image for 1400 UTC (16 bit integers) 014-017 Image for 1430 UTC (16 bit integers) 018-021 Image for 1500 UTC (16 bit integers) 022-025 Image for 1530 UTC (16 bit integers) 026-029 Image for 1600 UTC (16 bit integers) 030-033 Image for 1630 UTC (16 bit integers) 034-037 Image for 1700 UTC (16 bit integers) 038-041 Image for 1730 UTC (16 bit integers) 042-045 Image for 1800 UTC (16 bit integers) 046-049 Image for 1830 UTC (16 bit integers) 050-053 Image for 1900 UTC (16 bit integers) 054-057 Image for 1930 UTC (16 bit integers) 058-061 Image for 2000 UTC (16 bit integers) 062-065 Image for 2030 UTC (16 bit integers) 066-069 Image for 2100 UTC (16 bit integers) 070-073 Image for 2130 UTC (16 bit integers) 074-077 Image for 2200 UTC (16 bit integers) 078-081 Image for 2230 UTC (16 bit integers) 082-085 Image for 2300 UTC (16 bit integers) 086-089 Image for 2330 UTC (16 bit integers) 090-093 Image for 0000 UTC (next day) (16 bit integers) 094-097 Image for 0030 UTC (next day) (16 bit integers) 098-101 Image for 0100 UTC (next day) (16 bit integers) 102-105 Image for 0130 UTC (next day) (16 bit integers) 9. Data Manipulations 9.1 Formulae 9.1.1 Derivation Techniques and Algorithms The solar parameters were retrieved from GOES-7 visible images using a physical retrieval algorithm described in Gu and Smith (1997). The algorithm includes parameterization of Rayleigh scattering, water vapor and ozone absorption, aerosol and cloud attenuation, and surface reflection. The surface net LW flux was obtained from surface downward solar flux and in situ measured near-surface temperature using a statistical algorithm described in Gu et al. (1997). The basic theory behind this approach is that solar radiation provides the primary energy load modulating the fundamental daily cycle of net LW flux. Variation of surface temperature is the response of the surface to the incident solar energy, which affects the net LW flux through its effect on upward LW flux. 9.2 Data Processing Sequence None given. 9.2.1 Processing Steps None given. 9.2.2 Processing Changes None given. 9.3 Calculations None given. 9.3.1 Special Corrections/Adjustments None given. 9.3.2 Calculated Variables None given. 9.4 Graphs and Plots None. 10. Errors 10.1 Sources of Error Potential sources of error include: -- Calibration -- Model parameterization: cloud optical properties, Rayleigh scattering -- Uncertainties in input: column water vapor amount, aerosol optical depth -- Quality of level-1 data 10.2 Quality Assessment 10.2.1 Data Validation by Source The derived SW and LW images were compared with in situ measurements taken during IFC-2 of 1994 at Automated Meteorological Stations (AMS). See Gu and Smith (1997) and Gu et al. (1997) for details. 10.2.2 Confidence Level/Accuracy Judgment Compared to the downward solar and PAR data measured at the AMS sites during IFC-2 94, the rms errors (in W/m2) and relative rms errors in (%) are: downward solar downward PAR -------------- ------------ all sky: 77.9 (19.0%) 35.7 (21.4%) clear: 34.3 (6.49%) 16.6 (7.71%) partly cloudy: 86.2 (19.3%) 35.6 (19.3%) overcast/rain: 75.3 (35.8%) 42.5 (48.6%) heavy smoke: 75.1 (21.1%) 43.8 (32.5%) The mean differences in W/m2 (retrieved - AMS measured) are: downward solar downward PAR -------------- ------------ all sky: -6.7 10.9 clear: -8.2 6.3 partly cloudy: -11.0 6.6 overcast/rain: 6.1 25.0 heavy smoke: -1.2 19.8 The relative rms differences between the LW images and the in situ measurements taken at the 10 AMS sites are under 40% of the mean measured net LW flux. Note that the in situ measured net LW fluxes (L*) are calculated from measurements of net radiation (Rn) and net solar radiation (K*) i.e., L* = Rn - K*. Part of the rms differences may be a consequence of differences in leveling between the net pyrradiometers and albedometers mounted on some of the AMS towers (c.f. Gu et al., 1997, for details). 10.2.3 Measurement Error for Parameters See Section 11.2. 10.2.4 Additional Quality Assessments None given. 10.2.5 Data Verification by Data Center BORIS staff has viewed the imagery to verify image sizes, data type, and format. 11. Notes 11.1 Limitations of the Data See Section 11.2. 11.2 Known Problems with the Data The SW data overestimate both the broad-band and narrow-band surface albedo. Depending on solar zenith angle and surface type, the broad-band surface albedo is 5-30% larger than the albedometer measurements. This is partly due to the single-scattering assumption made to simplify the calculation of Rayleigh scattering. Adding in multiple scattering may reduce the surface albedo at high and low solar zenith angles by ~ 2 and 5%, respectively. The LW data values are high biased since we have used the near-surface thermodynamic temperature to replace the radiometric skin temperature. This is because there is only one thermal infrared channel in GOES-7 data, which is not sufficient to derive the radiometric temperature within a certain limit of error. For 1996, we will use the surface radiometric temperature retrieved from the split window of GOES-8 data. 11.3 Usage Guidance None given. 11.4 Other Relevant Information None given. 12. Application of the Data Set These data were derived for the purpose of using the radiation fields for temporal and spatial modeling at regional scales. 13. Future Modifications and Plans The plans for an improved SW algorithm will include: -- improvement in parameterization for Rayleigh scattering -- surface bidirectional reflectance model developed for BOREAS -- bidirectional reflectance model for clouds The plans for an improved LW algorithm will include: -- use of GOES-8 split window data to retrieve surface skin temperature -- addition of a nighttime algorithm 14. Software 14.1 Software Description There are README files and FORTRAN programs at our anonymous ftp site. The FORTRAN programs can be used to read the header, the image, or the lat-lon files. 14.2 Software Access To get on our anonymous ftp site, type: ftp metsat.met.fsu.edu username: anonymous password: your email address cd boreas -- for SW parameters: cd V1_products -- for net LW flux: cd L_net_products 15. Data Access 15.1 Contact for Data Center/Data Access Information These BOREAS data are available from the Earth Observing System Data and Information System (EOS-DIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The BOREAS contact at ORNL is: ORNL DAAC User Services Oak Ridge National Laboratory Oak Ridge, TN (865) 241-3952 ornldaac@ornl.gov ornl@eos.nasa.gov 15.2 Procedures for Obtaining Data BOREAS data may be obtained through the ORNL DAAC World Wide Web site at http://www-eosdis.ornl.gov/ or users may place requests for data by telephone, electronic mail, or fax. 15.3 Output Products and Availability Requested data can be provided electronically on the ORNL DAAC's anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes, or diskettes. The complete set of BOREAS data CD-ROMs, entitled "Collected Data of the Boreal Ecosystem-Atmosphere Study", edited by Newcomer, J., et al., NASA, 1999, are also available. 16. Output Products and Availability 16.1 Tape Products The level-2 GOES-7 SW and LW data can be made available on 8-mm tapes or Digital Archive Tapes (DAT). 16.2 Film Products None. 16.3 Other Products Although the inventory is contained on the BOREAS CD-ROM set, the actual GOES-7 images are not. See Section 15 for information about how to obtain the data. 17. References 17.1 Platform/Sensor/Instrument/Data Processing Documentation Bobotek, A., A.S. Hechtman, R.J. Komajoa, and P.G. Woolner. July 1995. GOES I-M System description. MITRE Corporation. Kelly, K.A. 1989. GOES I-M image navigation and registration and user Earth location. GOES I-M Operational Satellite Conf., Arlington, VA, US. Department of Commerce, NOAA, 154-167. Rossow, W.B., C.L. Brest, and M. Roiter. 1996. International Satellite Cloud Climatology Project (ISCCP) New Radiance Calibrations. WMO/TD-No. 736. World Meteorological Organization. Rossow, W.B., C.L. Brest, and M.D. Roiter. 1995. International Satellite Cloud Climatology Project (ISCCP): Update of radiance calibration report. Technical Document, World Climate Research Programme (ICSU and WMO), Geneva, Switzerland, 76 pp. Rossow, W.B., Y. Desormeaux, C.L. Brest, and A. Walker. 1992. International Satellite Cloud Climatology Project (ISCCP): Radiance calibration report. WMO/Technical Document No. 520, World Climate Research Programme and World Meteorological Organization (ICSU and WMO), Geneva, Switzerland, 104 pp. 17.2 Journal Articles and Study Reports Gu, J. and E.A. Smith. 1997. High-resolution estimates of total solar and PAR surface fluxes over large-scale BOREAS study area from GOES measurements. Journal of Geophysical Research 102(D24):29,685-29,705. Gu, J., E.A. Smith, G. Hodges, and H.J. Cooper. 1997. Retrieval of Daytime Surface Net Longwave Flux over BOREAS from GOES Estimates of Surface Solar Flux and Surface Temperature. Submitted to Canadian Journal of Remote Sensing. 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. Rossow, W.B., C.L. Brest, and M.D. Rotier. 1995. International satellite cloud climatology project (ISCCP): Update of radiance calibration. Technical Document, World Climate Research Program (ICSU and WMO), Geneva, Switzerland, 76 pp. 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. 17.3 Archive/DBMS Usage Documentation None. 18. Glossary of Terms None given. 19. List of Acronyms AOCS - Attitude and Orbit Control System ASCII - American Standard Code for Information Interchange ATS - Applications Technology Satellite BB - Broad-Band BOREAS - BOReal Ecosystem-Atmosphere Study BORIS - BOREAS Information System BPI - Bytes Per Inch CCT - Computer Compatible Tape CDA - Command and Data Acquisition CD-ROM - Compact Disk-Read-Only Memory DAAC - Distributed Active Archive Center DAT - Digital Archive Tape EOS - Earth Observing System EOSDIS - EOS Data and Information System FFC - Focused Field Campaign FOV - Field of View FSU - Florida State University GIS - Geographic Information System GMT - Greenwich Mean Time GOES - Geostationary Operational Environmental Satellite GSFC - Goddard Space Flight Center GVAR - GOES VARiable IFC - Intensive Field Campaign IFOV - Instantaneous Field of View IIFC - Inter IFC ISCCP - International Satellite Cloud Climatology Project LW - Longwave NAD83 - North American Datum of 1983 NASA - National Aeronautics and Space Administration NB - Narrow-Band NESDIS - National Environmental Satellite, Data and Information Service NLUT - Normalization Look-Up Table NOAA - National Oceanic and Atmospheric Administration N-S - North-South NSA - Northern Study Area NWS - National Weather Service ORNL - Oak Ridge National Laboratory PANP - Prince Albert National Park PAR - Photosynthetically Active Radiation PMT - Photomultiplier Tube RSS - Remote Sensing Science SBRS - Santa Barbara Remote Sensing SMS - Synchronous Meteorological Satellite SRB - Surface Radiation Budget SSA - Southern Study Area SW - Shortwave TOA - Top of the Atmosphere URL - Uniform Resource Locator VAS - VISSR Atmospheric Sounder VISSR - Visible and Infrared Spin-Scan Radiometer 20. Document Information 20.1 Document Revision Dates Written: 21-Feb-1997 Last Updated: 29-Sep-1999 20.2 Document Review Dates BORIS Review: 23-Sep-1998 Science Review: 20.3 Document ID 20.4 Citation When using these data, please include the following acknowledgment as well as citations of relevant papers in Section 17.2: The SRB data were provided by E.A. Smith and J. Gu of the Department of Meteorology, FSU. If using data from the BOREAS CD-ROM series, also reference the data as: Smith, E.A., "Surface Radiation Budget Retrieved from GOES-7 VISSR Imagery for Large Scale BOREAS Area." 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 Keywords: GOES-7 Emitted Radiation Reflected Radiation Water Vapor RSS14_GOES7_L2.doc 04/02/00