Radiation Budget from ERBE 1. TYPE OF DATA 1.1 Parameter/Measurement 1.2 Unit of Measurement 1.3 Data Source 1.4 Data Set Identification 2. SPATIAL CHARACTERISTICS 2.1 Spatial Coverage 2.2 Spatial Resolution 3. TEMPORAL CHARACTERISTICS 3.1 Temporal Coverage 3.2 Temporal Resolution 4. INSTRUMENT DESCRIPTION 4.1 Mission Objectives 4.2 Key Satellite Flight Parameters 4.3 Principles of Operation 4.4 Instrument Measurement Geometry 5. DATA PROCESSING SEQUENCE 5.1 Processing Steps and Data Sets 5.2 Derivation Techniques/Algorithms 5.3 Special Corrections/Adjustments 5.4 Processing Changes 6. QUALITY ASSESSMENT 6.1 Data Validation by Producer 6.2 Confidence Level/Accuracy Judgment 6.3 Usage Guidance 7. CONTACTS FOR DATA PRODUCTION INFORMATION 8. OUTPUT PRODUCTS AND AVAILABILITY 8.1 Tape Products 8.2 Film Products 8.3 Other Products 9. DATA ACCESS 9.1 Archive Identification 9.2 Procedures for Obtaining Data 9.3 NCDS Status/Plans 10. CONTACTS FOR ARCHIVE/DATA ACCESS INFORMATION 11. REFERENCES 11.1 Satellite/Instrument/Data Processing Documentation 11.2 Journal Articles and Study Reports 11.3 Archive/DBMS Usage Documentation 12. RELATED DATA SETS 13. SUMMARY/SAMPLE 14. NOTES ENDOFTOC 1. TYPE OF DATA 1.1 Parameter/Measurement. Earth radiances and solar irradiances in broad spectral bands are measured by two instrument packages: a scanner and a nonscanner, with characteristics listed in the following table: Earth Radiation Budget Satellite (ERBS), NOAA-9, and NOAA-10 ERBE Instrument Characteristics ________________________________________________________________________ Wavelength limits Channel (micrometers) Measurement ________________________________________________________________________ Fixed WFOV* 1 0.2 - 50.0 Total Radiance 2 0.2 - 5.0 Shortwave (SW) Reflected Fixed MFOV** 3 0.2 - 50.0 Total Radiance 4 0.2 - 5.0 SW Reflected Fixed Solar 5 0.2 - 50.0 Total Irradiance Monitor Scanning NFOV~ 1 0.2 - 50.0 Calibrated Radiance 2 0.2 - 5.0 SW Reflected 3 5.0 - 50.0 Longwave (LW) Emitted ________________________________________________________________________ * Wide field-of-view ** Medium field-of-view ~ Narrow field-of-view Albedo, radiant exitances, and solar irradiances are the geophysical parameters found in the ERBE Level-II and -III data sets. 1.2 Unit of Measurement. Nonscanner measurements in counts and in W/(m**2). Scanner measurements in counts and in W/m**2-sr. Albedo is unitless. 1.3 Data Source. The Earth Radiation Budget Experiment (ERBE) on ERBS, NOAA-9, and NOAA-10. 1.4 Data Set Identification. Solar Incidence data (S-2), Regional, Zonal and Global Averages (S-4), Processed Archival (PAT or S-8) data and the Earth Radiant Exitance and Albedo Scanner (S-9) and Nonscanner (S-10) data are archived on optical disks. 2. SPATIAL CHARACTERISTICS 2.1 Spatial Coverage. The spatial coverage differs with the channel and the spacecraft, as described below. Wide-angle Channels: These two fixed channels continuously view the earth disc. The measurements are continuous over the entire globe for NOAA-9 and NOAA-10, and between 57 degrees north and south latitudes for ERBS which precesses 4.95 degrees west per day. Medium-angle Channels: These two fixed channels continuously view a circle of nominally 5 degree radius at the top of the atmosphere. The measurements are continuous over the entire globe for NOAA-9 and NOAA-10, and between 57 degrees north and south latitude for ERBS which precesses 4.95 degrees west per day. Narrow-angle Channels: These three scanning channels continuously view small areas over the entire Earth. The cross-track scan field-of-view (FOV) is approximately 40 km at nadir, and there is a 35% FOV overlap at nadir for ERBS. NOAA-9 and -10 provide global coverage, and the ERBS satellite provides coverage between 57 degrees north and south latitude. 2.2 Spatial Resolution. The spatial resolution differs with the four types of channels and the two types of spacecraft (ERBS and NOAA). The wide-angle channels have a 136 degree FOV on ERBS and a 126 degree FOV on the NOAA satellite. The medium-angle channels have footprints of approximately a 5 degree radius or 1000 km at the top-of-the-atmosphere. The narrow-angle channels have an instantaneous hexagonal FOV with an angular size of 3 x 4.5 degrees, which is equivalent to a 31 km cross-track x 47 km along-track footprint at nadir for ERBS and 44 km cross-track x 65 km along-track for NOAA. The solar channel has an unencumbered FOV which observes the entire solar disk. Scanner gridded products are available at 2.5 x 2.5 degree resolution. In addition, scanner data are also available in 5 x 5 degree and 10 x 10 degree nested grids. Numerical filter (NF) nonscanner data are available in 5 x 5 degree resolutions and 10 x 10 degree nested grids. Shape factor (SF) nonscanner data are available in 10 x 10 degree resolutions in the S-4 output product. 3. TEMPORAL CHARACTERISTICS 3.1 Temporal Coverage. ERBS was launched October 5, 1984 and is still operational. NOAA-9 became operational in January 1985 and NOAA-10 in October 1986. The NOAA-9 scanner failed on January 20, 1987, the NOAA-10 scanner failed on May 22, 1989, and the ERBS scanner failed on February 28, 1990. ERBE nonscanner measurements on both NOAA satellites and the ERBS satellite are continuing (please see Item 14 concerning the ERBS nonscanner). All the Earth-viewing channels collect measurements continuously. The solar channel collects 20 minutes of usable data (about twice per month) during solar calibration periods. 3.2 Temporal Resolution. Data records are at sixteen-second intervals for the Level-II products. Gridded data are daily, monthly-hourly (hourly averages for a month), monthly-daily (daily averages for a month), and hourly (S-4, S-9, and S-10). S-9 and S-10 also include individual hour box estimates. 4. Instrument Description 4.1 Mission Objectives. The objectives of the Earth Radiation Budget Experiment (ERBE) are: (1) to determine for a minimum of 1 year the monthly average radiation budget on regional, zonal, and global scales, (2) to determine the equator-to-pole energy transport gradient, and (3) to determine the average diurnal variation of the radiation budget on a regional and monthly scale. 4.2 Key Satellite Flight Parameters. Nominal orbit parameters for ERBS are listed below: . Launch date October 5, l984 . Planned duration* 1 year . Actual duration (Scanner failed 02/28/90) . Orbit Non-sun synchronous . Semi-major axis 6988 km . Normal Altitude 610 km . Inclination 57 deg . Nodal period 98 min . Equator Crossing time Precesses Nominal orbit parameters for NOAA-9 are listed below: . Launch date December 12, l984 . Planned duration 1 year . Actual duration (Scanner failed 01/20/87) (Nonscanner failed 11/7/88) . Orbit Sun-synchronous . Semi-major axis 7248 km . Normal Altitude 872 km . Inclination 98 deg . Nodal period 102.08 min . Equator Crossing time 1430 Local Mean Solar Time, ascending Nominal orbit parameters for NOAA-10 are listed below: . Launch date September 17, l986 . Planned duration 1 year . Actual duration (Scanner failed 05/22/89) . Orbit Sun-synchronous . Semi-major axis 7211 km . Normal Altitude 833 km . Inclination 98 deg . Nodal period 101.2 min . Equator Crossing time 0730 Local Mean Solar Time, descending *The design life for all ERBE instruments is one year with a two-year goal. 4.3 Principles of Operation. The nonscanner package consists of four Earth-viewing channels, consisting of two MFOV, two WFOV channels, and a solar monitor. All five instruments are active cavity radiometers, with an accuracy of approximately 1% for spectral flatness and electrical substitution radiation detection. The Earth-viewing channels have two spectral ranges, one sensitive to all wavelengths and the other only to shortwave by means of a fused silica filter dome. Cavities are enclosed in modules which include filter domes and aperture limiters. The modules are mounted in an elevation beam, which can be rotated to point the detectors at the Earth, at the internal calibration sources, or at the Sun. The scanner package contains three NFOV radiometric channels each of which consists of an F/1.84 Cassegrain telescope. All are located within a single, rotating scan-head which scans the FOV across-track. The scan-head can also be rotated in azimuth at a slow rate. Each channel makes 74 measurements per scan. One channel has no filter and so absorbs all wavelengths. A second has a Suprasil-W1 filter which transmits only shortwave radiation. The third has a multilayer filter on a diamond substrate to reject shortwave and accept longwave radiation. 4.4 Instrument Measurement Geometry. The non-scanner modules can be rotated to any of three positions: launch/internal calibration position (180 degrees), the solar calibration position (78 degrees), and the Earth-viewing (nadir) position (0 degrees). The WFOV channels view the Earth from limb-to-limb. The MFOV channels are designed to include approximately an Earth view of 10 degrees within the unencumbered FOV. The scanner package can rotate in azimuth between 0 degrees and 180 degrees with an accuracy of 0.075 degrees. (The normal scan mode is cross-track.) The hexagonal IFOV of each channel has an angular size of 3 x 4.5 degrees, the longer dimension being along the satellite ground track. 5. DATA PROCESSING SEQUENCE 5.1 Processing Steps and Data Sets. Four products: the Solar Incidence (S-2), the Regional, Zonal and Global Averages (S-4), the Processed Archival (PAT or S-8), and the Earth Radiant Exitance and Albedo Scanner (S-9) and Nonscanner (S-10) optical disks are produced. The solar monitor channel of the nonscanner instrument collects about 20 minutes of usable data during solar calibration periods that occur approximately every two weeks. The solar data and other pertinent data collected per month per spacecraft are called the S-2 product. The S-4 product contains the time and space averages of all the individual estimates of radiant exitance at the top of the atmosphere per month per spacecraft. S-4 data are a combination of all operational spacecraft (ERBS, NOAA-9 and -10) data. It contains 4-second averaged measurements per month per satellite. The Earth Radiant Exitance and Albedo Scanner product (S-9) contains inverted daily, monthly-hourly (hourly averages for a month) and monthly averages of shortwave and longwave radiant exitance at the top of the atmosphere for ERBE scanner data per month, as well as individual hour box estimates per month. The S-10 disk contains the same information for the ERBE nonscanner. The Processed Archival disk (PAT or S-8) identifies scene type, computes shortwave and longwave unfiltered radiances, and estimates the radiant exitances at the top of the Earth's atmosphere for each scanner measurement and for 32-second nonscanner average measurements. 5.2 Derivation Techniques/Algorithms. In-flight calibration is performed to ensure high accuracy of radiometric measurements. The design and calibrations of the ERBE instrument are tied to the 1968 International Practical Temperature Scale and the World Radiometer Reference. There is at least one on-board calibration device for each channel. These devices, together with a space look which provides a near-zero radiance, give basic offset and gain information for periodic in-flight calibration of the instruments. The scanner measurements are converted, pixel by pixel, to radiances by use of spectral factors, and to radiant exitance at the top of the atmosphere by use of angular directional models. The nonscanner measurements are inverted by both a shape factor method and a numerical filter technique. 5.3 Special Corrections/Adjustments. Concurrent development of a mathematical model for each instrument helps in the understanding of instrument response in ground and in-flight calibration conditions and in space operation. 5.4 Processing Changes. The Hourly Grand Monthly Average (HGMA) net value was originally based only on the days where actual data was collected. The HGMA net value (for both total and clear sky) has been revised, in the operational Time Space Averaging (TSA) code, and now uses the integrated solar radiation summed over the entire month. This assumes that the albedo for the days with shortwave measurements is representative of the albedo for all the days of the month. Only one change has been made in the calculation of the Daily Grand Monthly Average (DGMA) shortwave value (for both total and clear sky). The DGMA shortwave value is now derived from integrated solar radiation for all days of the month. As with the HGMA, it is implicitly assumed that the albedo for days with shortwave measurements is the same as the albedo for all days of the month. No attempts have been made to fill in albedo values on days without shortwave measurements. A study showed that the impact of such a change was negligible on a global scale and, in addition, would be difficult and time consuming to implement in the operational code. Three additional improvements in the TSA code have been implemented. Minor corrections have been made in the procedures for handling fill values in regions which are illuminated for only a part of the month and have no shortwave measurements during the month. DGMA clear-sky longwave over land had previously been filled with fill values. Now the HGMA values will be used to fill these regions with appropriate clear-sky longwave results. These DGMA clear-sky longwave values over land are then used to calculate clear-sky net radiation for the land regions. This change makes the zonal and global average values for DGMA clear-sky longwave more meaningful. Integrated solar radiation (HGMA and DGMA) had previously been summed over only the days with shortwave measurements. Now the integrated solar radiation is summed over the entire month. 6. QUALITY ASSESSMENT 6.1 Data Validation by Producer. Recent experiences in validating ERBE data output products have revealed several shortcomings in the time-space averaging (TSA) algorithms for ERBE. In particular, sparse sampling, especially in the case of clear-sky shortwave data, causes significant inconsistencies in the monthly average results. This problem is evident from an examination of the two separate monthly average products: Hourly Grand Monthly Average (HGMA) and Daily Grand Monthly Average (DGMA). In the S-9, S-10 and S-4 Users guides, HGMA refers to monthly (hour) quantities and DGMA refers to monthly (day) quantities. The albedos are calculated differently for the S-9, S-10 and S-4 products. In creating the S-9 and S-10, albedos (DGMA) are calculated using the incoming solar radiation integrated over the days of the month in which shortwave data have been collected. Albedos (HGMA) are calculated in a similar manner except that the solar incoming radiation is summed rather than integrated. The albedos thus calculated are generally close to each other. In creating the S-4, albedos (DGMA and HGMA) are calculated using the integrated incoming solar. For S-9's, S-10's, and S-4's, the Net (DGMA and HGMA) use integrated solar incidence now. The shortwave has always been calculated the same way. These products were originally retained for comparison purposes. If one of the products was significantly different from the other, then that served to demonstrate that the sampling was inadequate. Unfortunately, when the results are related to the clear-sky shortwave flux the samples are often poor and, therefore, the results are questionable. 6.2 Confidence Level/Accuracy Judgment. A confidence level has not been determined for the ERBE data, and there are no immediate plans to do so. Some effort has been made to assess the accuracy of selected parameters (such as longwave and shortwave); however, a rigorous error analysis has not been undertaken. 6.3 Usage Guidance. A Monthly Product Summary (MPS) is currently available for PAT data, which includes an explanation of the data coverage for the month. The summary explains why an archival disk was not produced, and the reason for data dropouts. Global processing summaries are currently produced for the monthly products (S-9, S-10, and S-4). The S-9 and S-10 summary lists the regions located on a given disk and the number of satellites that were merged per region in order to obtain combined satellite data. The S-4 summary contains the number of records filled per region, zonal and global averages, and an output disk summary. It should be recalled that the monthly-hourly averaged results and the corresponding statistics (minimums, maximums, standard deviations) are a combination of measurements and models. The mean and standard deviation of these results, which are on the S-9 and S-10 data disks, represent the best estimates of the monthly-hourly results. However, the maximum and minimum values for the monthly-hourly parameters should be handled with caution because they include extrapolation or interpolation between measurements having many missing hours of data. (Note: A simple average of the measurements, in order to determine the monthly-hourly means, is not advised because the resultant diurnal cycle could be misleading.) The combination of measurements and models leads to a more reasonable estimate when compared to full-time sampling of the Geostationary Operational Environmental Satellite (GOES). 7. CONTACTS FOR DATA PRODUCTION INFORMATION 7.1 ERBE Experiment Scientist and Science Team Leader Dr. Bruce R. Barkstrom Atmospheric Sciences Division Mail Stop 420 NASA/Langley Research Center Hampton, Virginia 23665 (804) 864-5676 FTS 928-5676 7.2 ERBE Data Management Team Leader Mr. James F. Kibler Atmospheric Sciences Division Mail Stop 423 NASA/Langley Research Center Hampton, Virginia 23665 (804) 864-5386 FTS 928-5386 8. OUTPUT PRODUCTS AND AVAILABILITY 8.1 Optical Disk Products. The following data products are from ERBS, NOAA-9, and NOAA-10. 8.1.1 Processed Archival Data (PAT or S-8), Level-II. Medium/Specifications: 12-in. write-once-read-many (WORM) optical disks. "Earth Radiation Budget Experiment (ERBE) Data Management System Processed Archival Tape (S-8) PAT Users Guide." January 1985. Format and Content: The optical disks are created on Optimem drives in an Aquidneck system. This data was first generated on a CDC computer. The first file is a header record. All records are written in multiples of 8-bit bytes. After the header file, the second file contains a test record. The third file contains scale factors and offsets. The data file is comprised of 5400 16-second data records, which contain ERBE scanner and nonscanner measurements, their viewing angles at the top of the atmosphere and estimates of the radiant exitance based on these measurements. Data Quantity/Rate: Each physical record contains 16-seconds worth of data. There is one tape per day per spacecraft. There is one optical disk per month. Status: PAT data on optical disks are available from ERBS for the period November 1984 through September 1989 (discontinuous), from NOAA-9 for the period March 1985 through January 1987, and from NOAA-10 for the period February 1987 through July 1988 (discontinuous). Plans/Schedule: NSSDC will continue to archive these data. 8.1.2 Solar Incidence Data (S-2), Level-II. Medium/Specification: 12-in. WORM optical disks. "Earth Radiation Budget Experiment (ERBE) Data Management System Solar Incidence Tape (S-2) Users Guide." July 1985. Format and Content: The optical disks are created on Optimem drives in an Aquidneck system. This data was first generated on a CDC computer. The first file contains a header record. The second file begins with a scale factor record, an offset record, and a time offset record, followed by 16-second data records. All data are arranged in ascending time of the Julian date. The Solar Incidence disk (S-2), contains the solar data and the housekeeping data for the nonscanner. Data Quantity/Rate: Each physical record contains 16 seconds worth of data. There is one tape per spacecraft and one optical disk per month. Status: Data are available on optical disk from ERBS for the period November 1984 through May 1991, from NOAA-9 for the period March 1985 through January 1987, and from NOAA-10 for the period February 1987 through July 1988. Plans/Schedule: NCDS provides access to these data. 8.1.3 Regional, Zonal and Global Averages (S-4), Level-III. Medium/Specifications: 12-in. WORM optical disks. "Earth Radiation Budget Experiment (ERBE) Data Management System The Regional, Zonal and Global Averages (S-4) Users Guide." July 1991. Format and Content: The optical disks are created on Optimem drives in an Aquidneck system. These data were first generated on a CDC computer. The first file on each disk contains a header. The second file contains the scanner scale factors. The third file contains the nonscanner scale factors. Files 4 through 26 contain the data records. The S-4 disks provide monthly averages of radiant exitant values and albedos for regional, zonal and global levels at 2.5, 5, and 10 degrees resolution. Data Quantity/Rate: One tape contains one month of data from combined spacecraft (ERBS, NOAA-9, NOAA-10). These data are archived on the last Processed Archive Tape (PAT) optical disk of the month. Status: The regional, zonal, and global data on optical disk from ERBS, NOAA-9, and NOAA-10 are available for the period November 1984 to December 1988 (discontinuous). Plans/Schedule: NCDS provides access to these data. 8.1.4 Earth Radiant Exitance and Albedo Data, Level-III. Scanner (S-9) and Nonscanner (S-10); Medium/Specifications: 12-in. WORM optical disks. "Earth Radiation Budget Experiment (ERBE) Data Management System Earth Radiant Exitance and Albedo Scanner (S-9) and Nonscanner (S-10) Users Guides." June 1985. Format and Content: The optical disks are created on Optimem drives in an Aquidneck system. These data were first generated on a CDC computer. Each disk contains two files. The first file contains the standard ERBE header record. The second file contains the scale factors and the data records. Each S-9 disk contains inverted daily, monthly-hourly (hourly averages for a month), and monthly averages of shortwave and longwave radiant exitance at the top of the atmosphere for ERBE scanner data for one month. Each S-9 disk also contains individual hour box estimates. The S-10 disk contains the same information for the ERBE nonscanner data. Grids are provided at 2.5, 5, and 10 degree resolution. Data Quantity/Rate: One S-9 and four S-10 tapes are produced per satellite per month. If more than one satellite was operational during the month, one S-9 tape and a set of S-10 tapes, containing the combined multiple satellite data, was produced. These data sets are then archived on the last Processed Archive Tape (PAT) optical disk of the month. Status: S-9 and S-10 data from ERBS are available for the period November 1, 1984 through January 31, 1988, and from NOAA-9 for the period April 1, 1985 through October 31, 1986. S-9 and S-10 data are not available from NOAA-10. Plans/Schedule: NSSDC will continue to archive these data. 8.2 Film Products. None. 8.3 Other Products. 8.3.1 Solar Incidence (S-2) data from the ERBS Satellite in Common Data Format (CDF) Medium/Specification: Magnetic disk Format and Contents: The data are stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. The CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. This CDF file may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: ERBE-S2_ERBS; 5 files, 9.2 Kb Status: Data are available from October 25, 1984 through May 8, 1991. Plans/Schedule: NCDS will continue to support and update these data as they are received. 8.3.2 Solar Incidence (S-2) data from the NOAA-9 Satellite in Common Data Format (CDF) Medium/Specification: Magnetic disk Format and Contents: The data are stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. The CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. This CDF file may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: ERBE-S2_NOAA9; 5 files, 7.7 Kb Status: Data are available from January 23, 1985 through December 12, 1990. Plans/Schedule: NCDS will continue to support and update this data as they are received. 8.3.3 Solar Incidence (S-2) data from the NOAA-10 Satellite in Common Data Format (CDF) Medium/Specification: Magnetic disk Format and Contents: The data are stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. The CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. This CDF file may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: ERBE-S2_NOAA10; 6 files, 5.6 Kb Status: Data are available from October 22, 1986 through April 1, 1987. Plans/Schedule: NCDS will to continue support and update this data as they are received. 8.3.4 Combined Solar Incidence (S-2) data for the ERBS, NOAA-9, and NOAA-10 Satellites in Common Data Format (CDF) Medium/Specification: Magnetic disk Format and Contents: The data are stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. The CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. This CDF file may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: ERBE-S2_SAT-COMB; 1 file, 25.6 Kb Status: Data are available from October 25, 1984 through May 8, 1991. Plans/Schedule: NCDS will continue to support and update this data as they are received. 8.3.5 Regional, Zonal, and Global Averages (S-4) Wide Field-of-View Shape Factor (WFVSF) data in Common Data Format (CDF) Medium/Specification: Magnetic disk Format and Contents: The data are stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. The CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. These CDF files may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: ERBE-S4_WFVSF-MN (by year); 5 files, 1.2 Mb Status: Data are available from November 1984 through December 1988. Plans/Schedule: NCDS will continue to support and update these data as they are received. 8.3.6 Regional, Zonal, and Global Averages (S-4) Narrow Field-of-View (NFOV) data in Common Data Format (CDF) Medium/Specification: Magnetic disk Format and Contents: The data are stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. The CDF contains data and descriptions about the data. A standard software package called the "CDF Library" allows a user within an NCDS session to create and access these data and descriptions. This CDF file may be accessed within the Data Applications Subsystem of NCDS. Data Quantity/Rate: ERBE-S4_NFV-MNTH (by year); 5 files, 19.6 Mb Status: Data are available from November 1984 through December 1988. Plans/Schedule: NCDS will continue to support and update these data as they are received. 8.4.1 The Greenhouse Effect Detection Experiment (GEDEX) CD-ROM Medium/Specifications: CD-ROM in ISO 9660 standard Format and Content: The data on this disk will be stored in a special data-set-independent format, designated the Common Data Format (CDF). CDF was developed as a uniform method of storing and retrieving data on disk. A standard software packaged called the "CDF Library" will be included with this CD-ROM allowing a user to create and access these data and descriptions. The CD-ROM will consist of many different data sets related to the study of the Greenhouse Effect, including the Solar Incidence (S-2) data set and subsets of the Regional, Zonal, and Global Averages (S-4) data set, and the accompanying data set documentation. Data Quantity/Rate: 1 CD-ROM disk set. Status: Release date for this product is scheduled for early 1992. Plans/Schedule: Users interested in this product should contact NCDS staff for more details. 9. DATA ACCESS 9.1 Archive Identification. Central Data Services Facility Code 933 National Space Science Data Center NASA/Goddard Space Flight Center Greenbelt, Maryland 20771 (301) 286-6695 FTS 888-6695 9.2 Procedures for Obtaining Data. Users may submit requests for data by letter, telephone, personal visit, or through the NSI DECnet computer network at NSSDC::REQUEST. Data costs are dependent upon affiliation and sponsorship of the user program. Data are available at no cost to NASA personnel. Communication with the NSSDC Request Coordination Office is advised before ordering. Researchers who reside outside the USA should direct their requests to: World Data Center A for Rockets and Satellites Code 930.2 Goddard Space Flight Center Greenbelt, Maryland 20771 USA (301) 286-6695 9.3 NCDS Status/Plans. NCDS provides online access to the entire S-2 product in Common Data Format (CDF). The ERBE-S2 and ERBE-S4 (by year) data in CDF are accessible via the CDFBrowse, CDFList, and Graphics options within the Data Applications subsystem of the NCDS. To view these data specify the following: NCDS$DATA:ERBE-S2_ERBS NCDS$DATA:ERBE-S2_NOAA9 NCDS$DATA:ERBE-S2_NOAA10 NCDS$DATA:ERBE-S2_SAT-COMB NCDS$DATA:ERBE-S4_WFVSF-MN NCDS$DATA:ERBE-S4_NFV-MNTH 10. CONTACTS FOR ARCHIVE/DATA ACCESS INFORMATION Request Coordination Office Code 933 National Space Science Data Center Goddard Space Flight Center Greenbelt, Maryland 20771 (301) 286-6695 Goddard DAAC User Support Office NASA/Goddard Space Flight Center Code 935 Greenbelt, Maryland 20771 (301) 286-3209 FTS: 888-3209 NSI DECnet: NSSDCA@NCDSUSO INTERNET: NCDSUSO@NSSDCA.GSFC.NASA.GOV 11. REFERENCES 11.1 Satellite/Instrument/Data Processing Documentation. a. Rao, P.K., S.J. Holmes, R.K. Anderson, J.S. Winston, and P.E. Lehr, 1990. "Weather Satellites: Systems, Data and Environmental Applications." American Meteorological Society. Boston, Massachusetts. 11.2 Journal Articles and Study Reports. a. Avis, L.M., R.N. Green, J.T. Suttles, and S.K. Gupta, 1984. "A Robust Pseudo-Inverse Spectral Filter Applied to the Earth Radiation Budget Experiment (ERBE) Scanning Channels." NASA Tech. Memorandum 85781, NASA Langley Research Center, Hampton, Virginia. b. Barkstrom, B.R., 1984. "The Earth Radiation Budget Experiment (ERBE)." Bull. Amer. Met. Soc., 65:1170-1185. c. Barkstrom, B.R, and G.L. Smith, 1986. "The Earth Radiation Budget Experiment: Science and Implementation." J. Geophys. Res., 24:379-390. d. Barkstrom, B.R., E.F. Harrison, G. Smith, R. Green, J. Kibler, R. Cess, and the ERBE Science Team, 1989. "Earth Radiation Budget Experiment (ERBE) Archival and April 1985 Results." Bull. Amer. Met. Soc., 70:1254-1262. e. Barkstrom, B.R., E.F. Harrison, R.B. Lee, III, and the ERBE Science Team, 1990. "Earth Radiation Budget Experiment Preliminary Seasonal Results." EOS, 71:297-312. f. ERBE Science Team, l986. "First Data from the Earth Radiation Budget Experiment (ERBE)." Bull. Amer. Meteor. Soc., 67:818-824. g. Green, R.N., and G.L. Smith, 1991. "Shortwave Shape Factor Inversion of Earth Radiation Budget Observations." J. Atm. Sci., 48:390-402. h. Green, R.N., et al., 1990. "Intercomparison of Scanner and Nonscanner Measurements for the Earth Radiation Budget Experiment (ERBE)." J. Geophys. Res., 95:11,785-11,798. i. Harrison, E.F., et al., 1983. "Orbital and Cloud Cover Sampling Analyses for Multisatellite Earth Radiation Budget Data." J. Spacecr. Rockets, 20:491-495. j. Harrison, E.F., et al., 1988. "First Estimates of the Diurnal Variation of Longwave Radiation from the Multiple-Satellite Earth Radiation Budget Experiment (ERBE)." Bull. Amer. Meteor. Soc., 69:1144-1151. k. Harrison, E.F., et al., 1990. "Seasonal Variation of Cloud Radiative Forcing Derived from the Earth Radiation Budget Experiment." J. Geophys. Res., 94:18,687-18,703. l. Hartmann, D.L., and D. Doelling, 1991. "On the Net Radiative Effectiveness of Clouds." J. Geophys. Res., 96:869-891. m. Kopia, L.P., 1986. "The Earth Radiation Budget Experiment Scanner Instrument." Rev. Geophys., 24:400-406. n. Luther, M.R., J.E. Cooper, and G.R. Taylor, 1986. "The Earth Radiation Experiment Nonscanner Instrument." Rev. Geophys., 24:391-399. o. Ramanathan, V., et al., 1989. "Cloud-radiative Forcing and Climate: Results from the Earth Radiation Budget Experiment." Science, 243:57-63. p. Smith, G.L., R.N. Green, E. Raschke, L.M. Avis, B.A. Wielicki, and R. Davies, l986. "Inversion Methods for Satellite Studies of the Earth's Radiation Budget: Development of Algorithms for the ERBE Missions." Rev. of Geophys., 24:407-421. q. Wielicki, B.A., and R.N. Green, 1989. "Cloud Identification for ERBE Radiation Flux Retrieval." J. Appl. Met., 28:1133-1146. 11.3 Archive/DBMS Usage Documentation. a. ERBE Data Management Team, December, 1987. "ERBE Data Management System Processed Archival Tape, S-8, PAT Users Guide". NASA/ Langley, Hampton, Virginia. b. ERBE Data Management Team, December, 1987. "ERBE Processed Archival Tape Monthly Product Summary, April 1985, ERBS". NASA/Langley, Hampton, Virginia. c. ERBE Data Management Team, June, 1985. "ERBE Data Management System, Earth Radiant Exitance and Albedo, Scanner S-9, Nonscanner S-10 Users Guides," NASA/Langley, Hampton, Virginia. d. ERBE Data Management Team, July, 1991. "ERBE Data Management System, The Regional, Zonal and Global Averages, S-4 Users Guide." NASA/Langley, Hampton, Virginia. e. ERBE Data Management Team, August, 1989. "ERBE Monthly Medium- Wide Data Tape, S-7 Monthly MWDT Users Guide," NASA/Langley, Hampton, Virginia. f. Olsen, L.M, J.W. Closs, and F.E. Corprew, November 1991. "NASA's Climate Data System Primer: Version 4.0." EOS DAAC, NASA Goddard Space Flight Center, Greenbelt, Maryland. 12. RELATED DATA SETS Related data sets or information about related data sets are available. For more information, specify the following data sets within the search criteria screen of the Data Access subsystem of NCDS: ERB-MATRIX (Nimbus-7 Earth Radiation Budget's Gridded Product) ERBE-S4-G (Earth Radiation Budget Experiment's Global Product) ERBE-S4-Z (Earth Radiation Budget Experiment's Zonal Product) AVHRR-1B (NOAA Polar Orbiter Advanced Very High Resolution Radiometer) NOAA-HB (NOAA Heat Budget) 13. SUMMARY/SAMPLE Sample subsets are available in Common Data Format (CDF) for other ERBE-S4 regional, zonal, and global data sets. The CDF subsets are accessible via the CDFBrowse, CDFList, and Graphics options within the Data Applications subsystem of the NCDS. To view these sample subsets specify one of the following: NCDS$SMPL:ERBE-S4_MFVNF-DY NCDS$SMPL:ERBE-S4_MFVNF-HR NCDS$SMPL:ERBE-S4_MFVNF-MN NCDS$SMPL:ERBE-S4_MFVSF-DY NCDS$SMPL:ERBE-S4_MFVSF-HR NCDS$SMPL:ERBE-S4_MFVSF-MN NCDS$SMPL:ERBE-S4_WFVNF-DY NCDS$SMPL:ERBE-S4_WFVNF-HR NCDS$SMPL:ERBE-S4_WFVNF-MN NCDS$SMPL:ERBE-S4_WFVSF-DY NCDS$SMPL:ERBE-S4_WFVSF-HR NCDS$SMPL:ERBE-S4_WFVSF-MN NCDS$SMPL:ERBES4-G_NFOV-DAY NCDS$SMPL:ERBES4-Z_NFOV-DAY 14. NOTES NOAA-9 was used as a test bed for software modifications after NOAA-11 developed gyroscope problems. While testing the software, a command error resulted in a complete shutdown of all instruments on-board the NOAA-9 spacecraft on May 21, 1991. The ERBE nonscanner instrument on-board NOAA-9 was powered up on May 22, 1991, followed by the detector heaters on May 23, 1991. The nonscanner elevation beam was undefined once the nonscanner was powered up, and attempts to command the elevation beam to its correct position were unsuccessful. Although the telemetry data showed that the ERBE instrument was in no physical danger, further command testing of NOAA-9 was discontinued because of NOAA operational conflicts. These operational conflicts came to an end July 16, 1991 and command testing was resumed in order to recover normal operation of NOAA-9 (which was achieved July 25, 1991). Further testing of NOAA-11 software modifications occurred in late August to correct continuing gyroscope problems. Variables from the ERBE-S4_NFOV-DAY datatype (with their associated mnemonics) are listed here as an example. EPOCH Time Line Latitude LATITUDE Longitude LONGITUD Solar Incidence SOLAR_IN LW Radiant Exitance OLR SW Radiant Exitance SW_TOA Albedo ALBEDO LW Rad Ext-Clr OLR_CLR SW Rad Ext_Clr SWTOACLR Albedo_clr Sky ALBD_CLR Num Hours_LW NHOUR_LW Num Hours_SW NHOUR_SW Num Hours_LW Clr N_HR_LWC Num Hours_SW Clr N_HR_SWC A proposed S-7 product has not yet been produced; however, there are plans to produce S-7 data in the near future. *92/03/12