CERES SFC Readme File. 1.0 Introduction This readme file document provides information on the Clouds and Earth's Radiant Energy System (CERES) data sets: CER_SFC_TRMM-PFM-VIRS_Beta4 CER_SFC_TRMM-PFM-VIRS_Edition2B CER_SFC_Terra-FM1-MODIS_Beta1 CER_SFC_Terra-FM2-MODIS_Beta1 CER_SFC_Aqua-FM4-MODIS_Beta1 This document includes the following sections: Section 2.0 - Data Set Description Section 3.0 - Format and Packaging Section 4.0 - Science Parameters Information Section 5.0 - Description of Sample Read Software Section 6.0 - Implementing Sample Read Software Section 7.0 - Sample Output Section 8.0 - Additional Data Information (This section is optional) If users have questions, please contact the Langley ASDC User and Data Services Office at: Atmospheric Science Data Center User and Data Services Office Mail Stop 157D NASA Langley Research Center Hampton, Virginia 23681-2199 U.S.A. E-mail: support-asdc@earthdata.nasa.gov Phone: (757)864-8656 FAX: (757)864-8807 URL: http://eosweb.larc.nasa.gov 2.0 Data Set Description 2.1 Instrumentation Description For a complete description of the CERES experiment and instruments, please refer to the documentation provided at the URL http://asd-www.larc.nasa.gov/ceres/ASDceres.html. 2.2 Data Quality For a discussion regarding the quality of the CER_SFC_TRMM-PFM-VIRS_Beta4_015018 data set, please refer to the corresponding Quality Summary Document available from the URL http://eosweb.larc.nasa.gov/project/ceres/table_ceres.html. 2.3 Other pertinent information The CERES SFC product is produced from software maintained by the CERES TISA Working Group. For a detailed discussion of the algorithms employed by this software, see the CERES Algorithm Theoretical Basis Document for Grid TOA and Surface Fluxes for Instantaneous Surface Product (System 9.0) provided at the URL http://asd-www.larc.nasa.gov/ATBD/ATBD.html. 2.4 Science Contact 1. Dr. Bruce A. Wielicki, CERES Interdisciplinary Principal Investigator Mail Stop 420 Atmospheric Sciences Research Building 1250 21 Langley Boulevard NASA Langley Research Center Hampton, Virginia 23681-2199 U.S.A E-mail: b.a.wielicki@larc.nasa.gov FAX: (757)864-7996 Phone: (757)864-5683 2. Mr. David F. Young, TISA Working Group Chair Mail Stop 420 Atmospheric Sciences Research Building 1250 NASA Langley Research Center Hampton, Virginia 23681-2199 U.S.A E-mail: david.f.young@nasa.gov FAX: (757)864-7996 Phone: (757)864-5740 3. Rajalekshmy Raju, TISA Data Management Team member SAIC One Enterprise Parkway Hampton, VA 23699 U.S.A. E-mail: r.raju@larc.nasa.gov FAX: (757)825-4968 Phone: (757)827-4854 4. Joe Stassi, TISA Data Management Team member SAIC One Enterprise Parkway Hampton, VA 23699 U.S.A. E-mail: J.C.STASSI@larc.nasa.gov FAX: (757)825-4968 Phone: (757)827-4887 3.0 Format and Packaging 3.1 Sample Read Package Contents This package consists of the following files: 1. SFC_readhdf_daacv3.c This is the main program which accesses the HDF reading functions. It consists of several examples of accessing SDS and Vdata structures from the included sample SFC file. Comments are provided throughout the program. 2. SFC_readHDFfuncs_daacv3.c This is a file containing C functions that are linked with Program SFC_readhdf_daacv3.c and calls to the HDF library routines. 3. SFC_HDFread_daacv3.h This is a header file for Program SFC_readhdf_daacv3.c and the SFC HDF read functions. 4. compile_SFC_readhdf_daacv3 This is a sample script to compile the C programs in a UNIX environment. The script must be modified for different platforms to properly compile the programs and correctly link the HDF libraries. 5. DPC_SFC_R3V2.pdf This is a PDF file containing the CERES Data Products Catalog pages corresponding to this SFC data set. This file is a subset of the CERES Data Products Catalog found under the "Documentation" option at the following URL: http://asd-www.larc.nasa.gov/ceres/ASDceres.html The version of the CERES Data Products Catalog at this URL contains the latest information about the CERES products. It is possible for the SFC product structure to change over time, and thus future SFC pages may not correspond to this data set. A copy of the SFC pages corresponding to this data set have therefore been included with this package. 6. SFC_HDF_5rec_list_daacv3 This is an ASCII file containing a description of the data in the sample SFC file, CER_SFC_TRMM-PFM-VIRS_SampleReadFile_999999.199802Z09 7. CER_SFC_TRMM-PFM-VIRS_SampleReadFile_999999.199802Z09 This is a sample SFC file containing five Vdata records. This sample file is used by the examples in Program SFC_readhdf_daacv3.c 8. CER_SFC_TRMM-PFM-VIRS_SampleReadFile_999999.199802Z09.met This is the metadata file corresponding to the sample data file listed in Item 8. An ASCII metadata file is delivered with every data granule. The file is written in Object Descriptive Language (ODL) and contains information that is associated with the origin, content, quality, and condition of the data granule. The metadata information contained in the granule metadata file is also included as metadata on the SFC HDF data file. An example of a metadata parameter found in both the metadata file and the SFC HDF file is LOCALGRANULEID, which has a value set to the original granule file name. 3.2 Zip Information To read the files, first unzip them with Info-Zip software. Information about downloading and using this freeware is available at the URL http://www.info-zip.org/pub/infozip/Info-ZIP.html. 3.3 HDF library / NetCDF HDF information, documentation, tutorials, libraries, etc. can be found on-line at the URL http://hdf.ncsa.uiuc.edu. The utility hdp, provided in the HDF libraries, extracts information regarding the HDF file contents, such as the size, type, order, names, and the data itself. Some examples are: hdp -H - provides "help" on how to use the "hdp" utility hdp dumpvd - lists the options and format for viewing Vdatas hdp dumpsds - lists the options and format for viewing SDSs hdp dumpsds [-options] hdp dumpvd [-options] 3.4 Data Format The SFC data are written as a collection of HDF SDSs. As a convenience to users implementing tools such as HDF viewers, the SFC SDSs are organized into HDF Vgroups. 3.5 Breakdown of the File Naming Convention The SFC data granules adhere to the following CERES file naming convention: CER_PID_SS_PS_CC.DataDateZXX where: CER = the CERES experiment PID = the CERES product, e.g., SFC SS = the CERES sampling strategy, e.g., TRMM-PFM-VIRS, as defined by the CERES experiment. For the SFC, this indicates the satellite and instruments that were the source of the input data into the software system that produced the SFC data. PS = the CERES production strategy, e.g., 'Beta2', as defined by the CERES experiment. 'BetaN' production strategies usually indicate versions of the product produced with algorithms that are still being validated, and therefore have a restricted distribution. 'EditionN' production strategies usually indicate products that are available to the entire scientific community. CC = the product configuration code, e.g., '01316', assigned by the CERES experiment. This code is internal to the CERES project, and is updated whenever the software system producing the product is modified for any reason. For a complete history of the changes to the software, see the product Description/Abstract document available from the URL http://eosweb.larc.nasa.gov/project/ceres/table_ceres.html DataDate = the date of the data included in the file. For the SFC, this date is in the format YYYYMM where: YYYY = the four-digit data year, MM = the two-digit month ZXX = The HDF file number. There are maximum of 18 HDF files for SFC product. Each HDF file contains the regional data of 10 zones. e.g.,'Z09', contains the regional data of zones 80 - 90. 4.0 Science Parameters Information See the SFC CERES Data Products Catalog pages included with this package (listed under Section 3.1) for the following information for each science parameter: Name Units Type (integer, real, character, etc...) Ranges (minimum and maximum values) Fill values / bad data flags 5.0 Description of Sample Read Software The sample read software in this package is intended only as an example. As the number of SDSs that make up the SFC product is large and the number of data records contained on an actual SFC file is large, the sample software only demonstrates reading a limited number of SDSs for the number of data records included in the sample data file. The contents of the SFC record, along with a list of all the SDSs contained on the SFC product, are described in the Data Products Catalog pages discussed in Section 3.1. 6.0 Implementing Sample Read Software 6.1 Compiling the Sample Read Software 1. Download and install the HDF libraries from the NCSA web site http://hdf.ncsa.uiuc.edu This code uses version HDF4.1r3. Other versions of the HDF libraries may not work with this code. NCSA uses the gnu gzip compression utility for some packages. If necessary, the software needed to uncompress the file can be obtained from one of the Gnu mirror sites listed at the URL http://www.gnu.org/order/ftp.html 2. Edit the sample script 'compile_SFC_readhdf_daacv3' to link the HDF libraries and compile the C programs. Check the permissions on this file to make sure execute permission is set for the owner by typing at the command line (denoted by ">"): > ls -l compile_SFC_readhdf_daacv3 A line similar to the following will be displayed: -rwxr--r-- 1 OWNER GROUP 1450 Mar 6 14:49 compile_SFC_readhdf_daacv3 where OWNER and GROUP are the file owner and group information. The owner executable permission is the x in -rwxr--r--. To set the proper permissions, at the command line type: > chmod 744 compile_SFC_readhdf_daacv3 3. Execute the script 'compile_SFC_readhdf_daacv3' to create the executable SFC_rd by typing at the command line: > source compile_SFC_readhdf_daacv3 or, on some systems, type: > compile_SFC_readhdf_daacv3 6.2 How to Run the Sample Read Software Execute sfc_rd by typing at the command line: > sfc_rd 7.0 Sample Output The following is the screen output generated from executing the sfc_rd program with the provided sample file. > sfc_rd ********************************************************* * SFC Read Software * * * * Version: 2.0 * * * * Date: May, 2002 * * * * Contact: Atmospheric Science Data Center * * User and Data Services Office * * Mail Stop 157D * * NASA Langley Research Center * * Hampton, Virginia 23681-2199 * * U.S.A. * * * * E-mail: support-asdc@earthdata.nasa.gov * * Phone: (757)864-8656 * * FAX: (757)864-8807 * * * *********************************************************** Name of SFC HDF file to be read: < CER_SFC_TRMM-PFM-VIRS_SampleReadFile_999999.199802Z09 ********************************************************* * Example 1: SDS * ********************************************************* Region Number 28801.000000 ********************************************************* * Example 2: SDS * ********************************************************* REC# HourBox # 0001: 14 0002: 24 0003: 37 0004: 71 0005: 84 ********************************************************* * Example 3: SDS * ********************************************************* REC# Region # HourBox # SW TOA TotSky (mean) SW TOA TotSky (std) SW TOA TotSky (num_obs) 0001: 28801 14 2.793743e+02 2.793743e+02 2.793743e+02 0002: 28801 24 3.402823e+38 3.402823e+38 3.402823e+38 0003: 28801 37 3.402823e+38 3.402823e+38 3.402823e+38 0004: 28801 71 3.841447e+01 3.841447e+01 3.841447e+01 0005: 28801 84 4.900000e+01 4.900000e+01 4.900000e+01 CERES 32-bit Real Default = 3.402823e+38 CERES 32-bit Integer Default = 2.147484e+09 ********************************************************* * Example 4: CERES_Metadata * ********************************************************* ASSOCIATEDPLATFORMSHORTNAME = TRMM *** END OF PROGRAM *** 8.0 Additional Information Regarding the CERES SFC Data Sets. Last Updated: June 17, 2003 -----------------------------------------------------------------------------