1.  TITLE

1.1  Data Set Identification.

     Surface and Top of Atmosphere (TOA) Shortwave and Photosynthetically 
     Active Radiation (PAR) Fluxes.

     (Monthly 3-Hourly Fluxes ; UMD/Dept. Meteorology)

1.2  Data Base Table Name.

     Not applicable.

1.3  CD-ROM File Name.


     Where nnn_nnnn is the parameter directory name. The radiation data have 6
     types of parameters (see table below). Note:  capital letters indicate
     fixed values that appear on the CD-ROM exactly as shown here, lower case
     indicates characters (values) that change for each path and file.

     The format used for the filenames is: nnnymmhh.Z, where nnn is the 
     parameter descriptor(see table below), y is the last digit of the year 
     (e.g., 7=1987), mm is the month of the year (e.g., 12=December), and hh 
     is the first two digits in the hour (e.g., 12=1200 Greenwich Mean Time).  
     The filename extension (.Z), identifies the compression method used on 
     the data (see section 8.4).  Below is a table of actual file name 
     descriptors, directory names and full parameter names:

     Parameter Description              Directory Name            Descriptor
     Surface Shortwave Downward Flux    SUR_SWDN                         SSD
     Surface Shortwave Upward Flux      SUR_SWUP                         SSU
     TOA Shortwave Downward Flux        TOA_SWDN                         TSD
     TOA Shortwave Upward Flux          TOA_SWUP                         TSU
     Surface PAR Downward               SUR_PADN                         PAD
     Gap-Filling Flag                   FIL_FLAG                         FIL

1.4  Revision Date Of This Document.

     April 5, 1995.

                         2.  INVESTIGATOR(S)

2.1  Investigator(s) Name And Title.

     Drs. R.T. Pinker and I. Laszlo
     Department of Meteorology
     University of Maryland, College Park

2.2  Title Of Investigation.

     WCRP/SRB Project.

2.3  Contacts (For Data Production Information).

     |              |         Contact 1     |       Contact 2       |
     |2.3.1 Name    |Dr. R.T. Pinker        |Dr. I. Laszlo          |
     |2.3.2 Address |Department of          |Department of          |
     |              |Meteorology            |Meteorology            |
     |              |University of Maryland |University of Maryland |
     |      City/St.|College Park, MD       |College Park,MD        |
     |      Zip Code|20742                  |20742                  |
     |2.3.3 Tel.    |(301) 405-5380         |(301) 405-5378         |
     |2.3.4 Email   |   |   |

2.4  Requested Form of Acknowledgment.

     The 3-hourly radiation fluxes were produced at the Department of 
     Meteorology, University of Maryland by Drs. R.T. Pinker and I. Laszlo 
     under grants NA16RC0113-01 and NA36GP0386 from NOAA/Climate and Global 
     Change Program Operational Measurements and NAG5-914 from the National 
     Aeronautics and Space Administration, Earth Science and Applications 
     Division, Climate Research Program.

                            3.  INTRODUCTION

3.1  Objective/Purpose.

     Information on shortwave radiation and PAR is important for modeling
     evapotranspiration over land and in controlling biogeochemical cycles 
     in the oceans and over land. The objective of this project was to 
     develop methodologies to derive these parameters and their derivatives
     on a global scale, at temporal and spatial resolutions relevant for 
     climate modeling.

3.2  Summary of Parameters.

     Surface shortwave (SW) downward flux, surface SW upward flux, surface
     photosynthetically active radiation (PAR) downward flux, top of the
     atmosphere (TOA) downward SW flux and TOA SW upward flux. These 
     parameters are derived at three-hourly intervals and averaged over a 

3.3  Discussion.

     The derived parameters are based on satellite observations obtained under
     the ISCCP activity (Schiffer and Rossow, 1985). Use was made here of
     the C1 data which has spatial resolution of 2.5 X 2.5 degrees lat/long 
     and a temporal resolution of three hours. The results depend on the input 
     satellite data and on the quality of the auxiliary information used, such 
     as precipitable water and ozone, as available from ISCCP C1.

                        4.  THEORY OF MEASUREMENTS

No measurements were made directly by the investigators. Shortwave radiation 
and PAR were derived from an inference model. The primary inputs to the model 
came from satellite sources. ISCCP-C1 data sets were chosen as inputs here 
because most of the data for these sets came from operational satellite 
sources. Also, the cloud parameters derived by ISCCP are about the best 
currently available.  The data coverage is global.

The ISCCP C1 data used to derive the SW and PAR fluxes are produced from Stage 
B3, reduced resolution narrowband radiance (600 nm and 11,000 nm) measurements 
made by the imaging radiometers on five geostationary satellites (METEOSAT, 
INSAT, GMS, GOES-EAST and GOES-WEST) and at least one polar orbiting NOAA 
satellite (only one year of complete INSAT data have been obtained but they 
are not included here).

The ISCCP C1 data set used to derive the SW and PAR fluxes is described in 
Rossow and Schiffer (1991), Schiffer and Rossow (1983), and Schiffer and 
Rossow (1985). The angular models used in the inference model are described in 
Suttles et. al. (1988).

                                5.  EQUIPMENT

The basic instruments which made the measurements for ISCCP were the visible
and infrared imaging radiometers on-board geostationary and polar Sun-
synchronous satellites which were operational during the data period (January 
1, 1987 to December 31, 1988).  However, for this data set, only the final 
ISCCP-C1 products were used.  The details of the various satellite missions 
are beyond the scope of this document. Therefore, the various subsections of 
Sec. 5 do not apply to this project.  For additional information on equipment 
see references listed in Section 4.

5.1  Instrument Description.

     Not applicable.

     5.1.1  Platform.

            Not applicable.

     5.1.2  Mission Objectives.

            Not applicable.

     5.1.3  Key Variables.

            Not applicable.

     5.1.4  Principles of Operation.

            Not applicable.

     5.1.5  Instrument Measurement Geometry.

            Not applicable.

     5.1.6  Manufacturer of Instrument.

            Not applicable.

5.2  Calibration.

     See references listed in section 4 and Whitlock et. al. (1990).

     5.2.1  Specifications.

            Not applicable.


                     Not applicable.

     5.2.2  Frequency of Calibration.

            Not applicable.

     5.2.3  Other Calibration Information.

            Not applicable.

                              6.  PROCEDURE

6.1  Data Acquisition Methods.

     The data sets described in this document were acquired by the Goddard
     Distributed Active Archive Center (GDAAC) from Drs. R.T. Pinker and
     I. Laszlo, Department of Meteorology, University of Maryland.  The 
     ISCCP-C1 data used to create this data set are currently available from 
     User and Data Services at Langley DAAC, NASA Langley Research Center. For 
     additional information on data acquisition methods and procedure for 
     ISCCP data sets see the references in section 4.

6.2  Spatial Characteristics.

     The original radiation data acquired from the University of Maryland had
     a resolution of 2.5 X 2.5 degrees lat/long. The Goddard DAAC converted
     these data to a 1 X 1 degree lat/long grid (see section 9.3.1).

     6.2.1  Spatial Coverage.

            The coverage is global.  Data in file are ordered from north to 
            south and from west to east beginning at 180 degrees west and 90 
            degrees North.  Point (1,1) represents the grid cell centered at 
            89.5 N and 179.5 W (see section 8.4).

     6.2.2  Spatial Resolution.

            The data are given on an equal-angle lat/long grid that has a 
            spatial resolution of 1 X 1 degree lat/long.

6.3  Temporal Characteristics.

     6.3.1  Temporal Coverage.

            January 1, 1987 through December 31, 1988.

     6.3.2  Temporal Resolution.

            Three hourly intervals (0, 3, 6, 9, 12, 15, 18 and 21 hours GMT),
            averaged over a month.

                           7.  OBSERVATIONS

7.1  Field Notes.


                         8.  DATA DESCRIPTION

8.1  Table Definition With Comments.

     Not applicable.

8.2  Type of Data.

|                 8.2.1                     |           |         |          |
|Parameter/Variable Name                    |           |         |          |
|       |               8.2.2               |   8.2.3   |  8.2.4  |  8.2.5   |
|       |Parameter/Variable Description     |   Range   |  Units  | Source   |
|TOA_SWDN                                   |           |         |          |
|       |Top of atmosphere shortwave        |min = 0    |[Watts]  |ISCCP C1  |
|       |downward radiation flux            |max = 1400 |[m^-2]   |Radiances |
|       |                                   |fill =     |         |          |
|       |                                   |-9999.000  |         |          |
|       |                                   |           |         |          |
|TOA_SWUP                                   |           |         |          |
|       |Top of atmosphere shortwave upward |min = 0    |[Watts]  |ISCCP C1  |
|       |radiation flux                     |max = 600  |[m^-2]   |Radiances |
|       |                                   |fill =     |         |          |
|       |                                   |-9999.000  |         |          |
|       |                                   |           |         |          |
|SUR_SWDN                                   |           |         |          |
|       |Surface shortwave downward         |min = 0    |[Watts]  |ISCCP C1  |
|       |radiation flux                     |max = 1100 |[m^-2]   |Radiances |
|       |                                   |fill =     |         |          |
|       |                                   |-9999.000  |         |          |
|       |                                   |           |         |          |
|SUR_SWUP                                   |           |         |          |
|       |Surface shortwave upward radiation |min = 0    |[Watts]  |ISCCP C1  |
|       |flux                               |max = 600  |[m^-2]   |Radiances |
|       |                                   |fill =     |         |          |
|       |                                   |-9999.000  |         |          |
|       |                                   |           |         |          |
|SUR_PADN                                   |           |         |          |
|       |Surface photosynthetically active  |min = 0    |[Watts]  |ISCCP C1  |
|       |radiation (PAR) downward flux      |max = 600  |[m^-2]   |Radiances |
|       |                                   |fill =     |         |          |
|       |                                   |-9999.000  |         |          |
|       |                                   |           |         |          |
|FIL_FLAG                                   |           |         |          |
|       |Flag to indicate whether radiation |min = 0.000|         |3-hourly  |
|       |data were "observed" or "filled".  |max = 1.000|         |and       |
|       |A flag value of 0 means data were  |fill =     |         |daily     |
|       |derived from 3-hourly radiances,   |-9999.000  |         |fluxes    |
|       |a value of 1 means data were       |           |         |          |
|       |estimated from the daily value of  |           |         |          |
|       |fluxes (see 9.3.1).                |           |         |          |
|       |                                   |           |         |          |

     1.000 denotes missing data in GAP-FILLING FLAG file.
     -9999.000 denotes fill value used for nighttime, in all files.

8.3  Sample Data Base Data Record.

     Not applicable.

8.4  Data Format.

     Compressed format:

     This data has been compressed using Unix Compress.  Compress uses 
     the modified Lempel-Ziv algorithm popularized in "A Technique for High 
     Performance Data Compression", Terry A. Welch, IEEE Computer, vol. 17, 
     no. 6 (June 1984), pp. 8-19.  Common substrings in the file are first 
     replaced by 9-bit codes 257 and up.  When code 512 is reached, the 
     algorithm switches to 10-bit codes and continues to use more bits until 
     the limit specified by the -b flag is reached (default 16).  Bits must be 
     between 9 and 16.  The default can be changed in the source to allow 
     compress to be run on a smaller machine.

     The amount of compression obtained depends on the size of the input, the
     number of bits per code, and the distribution of common substrings.  This 
     data has been reduced by approximately 85%.  So watch out!!!

     The data described here can be de-compressed using the platform specific 
     programs listed below. 

     DOS       MAC               UNIX         VMS        
     ----------------------------------------------------   MacGzip0.3b2      gzip1-2-3    gzip-1-2-3

     These programs are located in the SOFTWARE directory on this CD-ROM.  The 
     programs are also available via FTP from many archival data bases on the 
     Internet.  Information on anonymous FTP sites which supply these software 
     can be obtained via anonymous FTP at in the directory 
     /doc/pcnet in the file compression.

     Uncompressed format:

     The CD-ROM file format is ASCII, and consists of numerical fields of 
     varying length, which are space delimited and arranged in columns and 
     rows.  Each column contains 180 numerical values and each row contain 360 
     numerical values.  

          Grid arrangement

     The CD-ROM file format is ASCII, and consists of numerical fields of 
     varying length, which are space delimited and arranged in columns and 
     rows.  Each column contains 180 numerical values and each row contain 360 
     numerical values.  

          Grid arrangement

             I  = 1 IS CENTERED AT 179.5W
             J  = 1 IS CENTERED AT 89.5N

             90N - | - - - | - - - | - - - | - -
                   | (1,1) | (2,1) | (3,1) |
             89N - | - - - | - - - | - - - | - -
                   | (1,2) | (2,2) | (3,2) |
             88N - | - - - | - - - | - - - | - -
                   | (1,3) | (2,3) | (3,3) |
             87N - | - - - | - - - | - - - |
                  180W   179W    178W   177W


8.5  Related Data Sets.

     Langley Research Center radiation data on this CD-ROM.
     ISCCP-C1 data.

                         9.  DATA MANIPULATIONS

9.1  Formulas.

     9.1.1  Derivation Techniques/Algorithms.

            Estimates of SW and PAR fluxes are obtained from an inference
            method described in Pinker and Laszlo (1992).

            In the inference method, spectral upward and downward fluxes at
            the boundaries of the atmosphere are computed by determining the 
            atmospheric transmission and reflection and the surface albedo
            pertaining to a particular satellite observation. The spectral 
            intervals are: 0.2-0.4, 0.4-0.5, 0.5-0.6, 0.6-0.7 and 0.7-4.0

            The procedure includes the conversion of satellite-measured 
            visible (0.6 microns) clear and cloudy radiances into broadband 
            (0.2-4.0 microns) albedos, and the selection of the appropriate 
            transmittances and reflectances from a data library. The data
            library holds spectral transmittances and TOA reflectances for a 
            variety of atmospheric conditions, and is built from an 
            atmospheric radiation model. The radiation model accounts for the 
            absorption and multiple scattering of shortwave radiation by water 
            vapor, ozone, aerosol and cloud droplets in a vertically 
            in homogeneous atmosphere. Absorption by water vapor and ozone is 
            parameterized, and the transfer of radiation is computed from the 
            delta-Eddington approximation. 

            The transmittances and reflectances are selected by comparing the
            satellite-derived TOA broadband albedos to TOA albedos obtained 
            from the data library. The latter albedos are computed from the
            ozone and water vapor data in the ISCCP C1 data set, and from the
            surface albedo determined from a TOA albedo representing average
            clear-sky conditions (clear-sky composite).

            The upward (up) and downward (down) fluxes (F) at Tope of 
            Atmosphere (TOA) and at the surface (srf) are computed from the 
            following equations:

               F(toa,down) = PI * F0 * cos(THETA0)

               F(toa,up)   = F(toa,down) * ( R0(THETA0) + r * TTILDA )

               F(srf,down) = F(srf,down,dir) + F(srf,down,dif)
                           = F(toa,down) * ( T0(dir,THETA0) + T0(dif,THETA0)     
                             + r * RTILDA )

               F(srf,up) = a(dir) * F(srf,down,dir) + a(dif) * F(srf,down,dif)

               r = ( a(dir,THETA0) * T0(dir,THETA0) + 
                     a(dif,THETA0) * T0(dif,THETA0) ) / 
                   ( 1 - a(dif,THETA0) * RTILDA ),


                        THETA0 = solar zenith angle (degrees),
                         PI*F0 = extraterrestrial solar irradiance (Wm^-2),
                    R0(THETA0) = atmospheric reflectance,
                    T0(THETA0) = atmospheric transmittance,
               F(srf,down,dir) = direct surface downward flux (Wm^-2),
               F(srf,down,dif) = diffuse surface downward flux (Wm^-2),
               T0(dir,THETA0)  = direct transmittance,
               T0(dif,THETA0)  = diffuse transmittance,
                        a(dir) = direct surface albedo,  
                        a(dif) = diffuse surface albedo,
                        RTILDA = spherical reflectance,
                        TTILDA = spherical transmittance.

            Integration of the spectral fluxes for the interval of 0.4-0.7
            microns gives PAR, while integration over the wavelengths of 
            0.2-4.0 microns yields the shortwave radiation.

9.2  Data Processing Sequence.

     9.2.1  Processing Steps and Data Sets.

            1) The clear-sky, clear-sky composite and cloudy-sky radiances
               of the ISCCP C1 data are converted into broadband albedos.

            2) Surface albedo is derived from the clear-sky composite TOA
               broadband albedo and ISCCP C1 ozone and water vapor amounts.
               Climatological value of the aerosol optical depth is assumed.

            3) From the transmittance/reflectance data library, clear-sky and
               cloudy-sky TOA albedos are computed for a set aerosol and cloud
               optical depths using ISCCP C1 ozone and water vapor amounts and
               the surface albedo derived in step 2.

            4) The transmittance and reflectance pertaining to the satellite
               observation are selected by comparing the computed and
               satellite-derived TOA albedos. Clear-sky and cloudy-sky fluxes
               for every three hours are computed. All-sky fluxes are obtained
               by weighting the clear-sky and cloudy-sky fluxes with ISCCP C1
               cloud cover data.

            5) For every three hours, and for each grid, fluxes are adjusted
               to the solar zenith angle calculated for the center of grid.

            6) The all-sky, three-hourly fluxes are averaged over a month.  

     9.2.2  Processing Changes.

            The data were produced with Version 1.1 of the model as currently
            available at NASA LaRC SDAC.

9.3  Calculations.

     9.3.1  Special Corrections/Adjustments.

            See step 5 in Section 9.2.1.

            Due to missing observations and the lack of geostationary 
            satellite data along the 75 deg. E meridian, there are gaps in the 
            three-hourly global coverage. These gaps are filled in from the 
            daily flux values for the daylight hours by dividing the monthly 
            averages of daily fluxes by the monthly average of the daily solar 
            zenith angle cosines, and then multiplying the result by the 
            monthly average of the three-hourly solar zenith angle cosines.

            Below is a description of the re-gridding process done by the 
            Goddard DAAC:

               The original data consisted of 2.5 x 2.5 degree equal angular 
               grid values, starting at 0 longitude, -90 latitude, and 
               progressing eastward and then northward to 360 longitude, 90 

               The Goddard DAAC regridded each latitude and longitude band of 
               data by implementing the following steps:

               1) Replicate every data value in each latitude band 360 times, 
                  assigning them to a temporary array.  Each of the original 
                  latitude bands had 144 data values, which replicated 360 
                  times produces a temporary array of 51840 data values for 
                  that latitude band.
               2) The first 144 (temporary array) data values are summed and 
                  then divided by the number (144) of original latitude band 
                  values. This was repeated 359 more times, for every 144 
                  (temporary array) data values, in affect performing a linear 
                  interpolation of the data within the latitude band.
               3) Step 1 and 2 were repeated until all latitude bands have 
                  been interpolated.
               4) The same method, discussed above, was used for regridding 
                  each longitude band of data, except that the number of 
                  replications was 180.
               5) The resulting array of data values were then split and 
                  shifted from 0 longitude -> 360 longitude to -180 longitude 
                  -> 180 longitude.
               6) These data were then fliped from -180 longitude, -90 
                  latitude to -180 longitude, 90 latitude.

9.4  Graphs and Plots.


                          10.  ERRORS

10.1  Sources of Error.

      Errors can come from the satellite observations, from the inference 
      model used and from auxiliary input data. Satellite calibration accuracy 
      is of major concern. The observations come from several satellites 
      (e.g., GOES, GMS, METEOSAT, polar orbiters) which have different 
      spectral intervals. Also, the viewing angles differ and current angular 
      models require improvements. The radiative transfer component of the 
      inference model has been tested in the framework of the Intercomparison 
      of Radiation Codes in Climate Models (ICRCCM). Not all the auxiliary 
      information required for driving the model, however, is available.

10.2  Quality Assessment.

      10.2.1  Data Validation by Source.

              An ongoing effort is in progress to validate the derived
              parameters. The validation effort for SW is done at NASA LaRc
              using the GEBA archive (Ohmura and Gilgen, 1993). The validation
              effort for PAR is done at the University of Maryland.

      10.2.2  Confidence Level/Accuracy Judgment.

              Comparison of SW data with ground observations at a limited 
              number of European stations from GEBA shows a bias error of less
              than 9 [W] [m^-2] and total RMS error of 18 [W] [m^-2] for most 
              months.  Inclusion of other GEBA sites increases the error 

      10.2.3  Measurement Error for Parameters and Variables.

              Not available at this revision.

      10.2.4  Additional Quality Assessment Applied.


                             11.  NOTES

11.1  Known Problems With The Data.

      Not available at this revision.

11.2  Usage Guidance.

      Not available at this revision.

11.3  Other Relevant Information.

      Not available at this revision.

                           12.  REFERENCES

12.1  Satellite/Instrument/Data Processing Documentation.

      Rossow, W.B. and R.A. Schiffer, 1991. ISCCP cloud data products, Bull.
          Amer. Meteor. Soc., 72:2-20.
      Schiffer, R.A., and W.B. Rossow, 1983. The International Satellite Cloud
          Climatology Project(ISCCP): The first project of the World Climate
          Research Programme, Bull. Amer. Meteor. Soc., 64:779-984.
      Schiffer, R.A., and W.B. Rossow, 1985. ISCCP global radiance data set:
          A new resource for climate research. Bull. Amer. Meteor. Soc.,
      Suttles, J.T., R.N. Green, P. Minnis, G.L. Smith, W.F. Staylor, B.A.
          Wielicki, I.J. Walker, D.F. Young, V.R. Taylor, and L.L. Stowe,
          1988. Angular radiation models for earth atmosphere  system, 134pp.,
          Washington, D.C., (NASA Ref. Publ., 1184).
      Whitlock,C.H., T.P.Charlock, W.F.Staylor, R.T.Pinker, I.Laszlo,
          R.C.DiPasquale, and N.A.Ritchey, 1993. Description of WCRP surface
          radiation budget shortwave data set (version 1.1), NASA Technical
          Memorandum, 10774.

12.2  Journal Articles and Study Reports.

      Frouin, R. and R.T. Pinker, 1994. Estimating Photosynthetically Active
          Radiation (PAR) at the earth's surface from satellite observations.
          Remote Sensing of the environment, in press.
      Ohmura. A., and Gilgen, H., 1993. Evaluation of the global energy
          balance, Geophy. Monogra. 75, American Geophy. Union, 15:93-110.
      Pinker,R.T., and I.Laszlo, 1992. Modeling surface solar irradiance
          for satellite solar irradiance applications on a global scale.
          J. Appl. Meteor., 31:194-211.
      Pinker, R.T. and I. Laszlo, 1992. Global distribution of photosynthe-
          tically  active radiation as observed from satellites. J. Climate,
      Pinker, R.T., I. Laszlo and F. Miskolczi, 1993. Photosynthetically
          active radiation from satellite observations. IRS '92,  Tallinn,
          Estonia, 3-9 August 1992.
      Pinker, R.T., R. Frouin and Z. Li, 1994. A review of satellite methods
          to derive surface shortwave radiation fluxes. Remote sensing of the
          Environment, in press.
      Pinker, R.T., F. Miskolczi, and I. Laszlo, 1994. Validation of a
          satellite inference method to derive photosynthetically active
          radiation. Eighth Conference on Atmospheric Radiation, 74th AMS
          Annual meeting, 23-28 January 1994, Nashville, TN.
      Pinker, R.T., I. Laszlo, and F. Miskolczi, 1994. Photosynthetic climate
          in selected regions during the north hemispheric growing season.
          Global Biogeochemical cycles, 8:117-125.
      Rossow,W.B., and L.Garder, 1984. Selection of a map grid for data
          analysis and archival. J.Climate and Appl. Meteor., 23:1253-57.
      Schiffer,R.A., and W.B.Rossow, 1983. The International Satellite Cloud
          Project(ISCCP): The first project of the World Climate Research
          Programme, Bull. Amer. Meteor. Soc., 64:779-984.
      Welch, T.A., 1984.  A Technique for High Performance Data Compression. 
          IEEE Computer, 17(6):8-19.
      Whitlock,C.H., Staylor,W.F., Smith,G., Levin,R., Frouin.R, Gautier.C.,
          Teillet,P.M., Slater,P.N., Kaufman, Y.J., Holben,B.B., Rossow,W.B.,
          Brest,C.L., and Lecroy,S.R., 1990. AVHRR and VISSR satellite
          instrument caliberation results for both Cirrus and Marine Stratus
          IFO periods. NASA Conf. Proc., 3083:141-145.
      Whitlock, C.H., W.F. Staylor, W.L. Darnell, M.D. Chou, G. Dedieu, P.Y.
          Deschamps, J. Ellis, C. Gautier, R. Frouin, R.T. Pinker, I. Laszlo,
          W.B. Rossow, and D. Tarpley, 1990a. Comparison of surface radiation
          budget satellite algorithms for downwelled shortwave irradiance with
          Wisconsin FIRE/SRB surface-truth data. Proc. of the 7th Conf. on
          Atmospheric Radiation, San Francisco, July 23-27, 1990. Published by
          the American Meteorological Society, Feb. 4(9):237-242.

12.3  Archive/DBMS Usage Documentation.

      Contact the EOS Distributed Active Archive Center (DAAC) at NASA Goddard
      Space Flight Center (GSFC), Greenbelt Maryland (see Section 13 below).
      Documentation about using the archive or information about access to the
      on-line information system is available through the GSFC DAAC User
      Services Office.

                             13.  DATA ACCESS

13.1  Contacts for Archive/Data Access Information.

      GSFC DAAC User Services
      NASA/Goddard Space Flight Center
      Code 902.2
      Greenbelt, MD 20771

      Phone:     (301) 286-3209
      Fax:       (301) 286-1775

13.2  Archive Identification.

      Goddard Distributed Active Archive Center
      NASA Goddard Space Flight Center
      Code 902.2
      Greenbelt, MD 20771

      Telephone:  (301) 286-3209
      FAX:        (301) 286-1775

13.3  Procedures for Obtaining Data.

      Users may place requests by accessing the on-line system, by sending 
      letters, electronic mail, FAX, telephone, or personal visit.

      Accessing the GSFC DAAC Online System:

      The GSFC DAAC Information Management System (IMS) allows users to 
      ordering data sets stored on-line.  The system is open to the public.

      Access Instructions:

      Node name:
      Node number:
      Login example: telnet
      Username:  daacims
      password:  gsfcdaac

      You will be asked to register your name and address during your first

      Ordering CD-ROMs:

      To order CD-ROMs (available through the Goddard DAAC) users should 
      contact the Goddard DAAC User Support Office (see section 13.2).

13.4  GSFC DAAC Status/Plans.

      The ISLSCP Initiative I CD-ROM is available from the Goddard DAAC.


14.1  Tape Products.


14.2  Film Products.


14.3  Other Products.


                       15.  GLOSSARY OF ACRONYMS

AVHRR         Advanced Very-High Resolution Radiometer
GEBA          Global Energy Budget Archive
GOES          Geostationary Operational Environmental Satellite
ICRCCM        InterComparison of Radiation Codes in Climate Models
ICSU          International Council for Scientific Unions
ISCCP         International Satellite Cloud Climatology Project
LaRc          Langley Research Center
LW            Longwave Radiation
NASA          National Aeronautics and Space Administration
NOAA          National Oceanic and Atmospheric Administration, U.S.A.
PAR           Photosynthetically Active Radiation
SDAC          Satellite Data Analysis Center
SRB           Surface Radiation Budget
SW            Shortwave radiation
TOA           Top-of-the-atmosphere
TOVS          TIROS Operational Vertical Sounder
UMD           University of Maryland at College Park
WCRP          World Climate Research Programme (ICSU and WMO)
WMO           World Meteorological Organization