CERES R5-988 Readme File 1.0 Introduction This readme file document provides information on the Clouds and Earth's Radiant Energy System (CERES) ISCCP-D2like data sets. CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Edition3A_300300 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 Science, Users 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: https://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://ceres.larc.nasa.gov/ceres 2.2 Data Quality For a discussion regarding the quality of the ISCCP-d2like-Mrg data set, please refer to the corresponding Quality Summary Document available from the URL https://eosweb.larc.nasa.gov/sites/default/files/project/ceres/quality_summaries/CERES_ISCCP-D2like-Mrg_Ed3.pdf 2.3 Science Representatives 1. Dr. Norman G. Loeb, CERES Interdisciplinary Principal Investigator NASA Langley Research Center Mail Stop 420 Hampton, Virginia 23681-2199 E-mail: Norman.G.Loeb@nasa.gov FAX: (757)864-7996 Phone: (757)864-5688 2. Mr. David R. Doelling, TISA Working Group Chair NASA Langley Research Center Mail Stop 420 Hampton, Virginia 23681-2199 E-mail: david.r.doelling@nasa.gov FAX: (757)864-7996 Phone: (757)864-2155 3.0 Format and Packaging This package includes a program, written in C, which will read an ISCCP-D2like-Mrg HDF file. The examples provided in the main (ISCCP-D2like_readhdf.c) program are written specifically for SDS(s) and Vdata(s) in ISCCP-D2like-Mrg files. This read program is provided as a template to the user who will need to modify it, if they need to read different ISCCP-D2like-Mrg parameters. Information on the structure of the ISCCP-D2like-Mrg file can be found in the Data Products Catalog (DPC) pages included in this package. This information is also available in the enclosed dump file, CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.dump. 3.1 Sample Read Package Contents This package consists of the following files: 1) CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2 2) CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.met 3) CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.dump 4) DPC-ISCCP-D2like-Mrg_GEO-MODIS-DAY_R5V2.pdf 5) ISCCP-D2like_HDFread.h 6) ISCCP-D2like_readHDFfuncs.c 7) ISCCP-D2like_readhdf.c 8) compile_ISCCP-D2like_readhdf Descriptions for each file is as follows: 1) 'CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2' a sample 1-region CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2 which is used by the examples in 'ISCCP-D2like_readhdf.c' 2) 'CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.met' is an ASCII metadata file that 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 ISCCP-D2like-Mrg HDF data file. An example of a metadata parameter found in the metadata file and on the ISCCP-D2like-Mrg HDF file is LOCALGRANULEID, which has a value set to the original granule file name. 3)'CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.dump' is an ASCII file containing a description of the data in the sample ISCCP-D2like-Mrg 'CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2'. If a value in the ISCCP-D2like-Mrg granule is out-of-range or not valid, a default value is inserted in its place. Default values depend on data type. CERES default values are greater than or equal to: INT2 - 32767 INT4 - 2147483647 REAL4 - 3.402823E+38 REAL8 - 1.797693134862315E+308 The 'CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.dump' file includes a list of ALL the data on the 5 footprint sample ISCCP-D2like-Mrg (128 parameters/SDS's plus header Vdata. The output data are the same as what the user would produce using hdp, but for this example, the CERES Team modified the format of the output from the hdp command to make it easier to read. 4)'ISCCP-D2like-Mrg_DPC_R5V2.pdf' is a copy of the CERES Data Product Catalog pages which describes the ISCCP-D2like-Mrg product. 5)'ISCCP-D2like_HDFread.h' is a header file for 'ISCCP-D2like_readhdf.c' and the ISCCP-D2like-Mrg HDF read functions. 6)'ISCCP-D2like_readHDFfuncs.c' is a file consisting of C functions that are linked with 'ISCCP-D2like_readhdf.c' and call the HDF functions. 7)'ISCCP-D2like_readhdf.c' is the main program which accesses the HDF reading functions. It consists of six examples of accessing SDS and Vdata structures from the included sample ISCCP-D2like-Mrg file. Comments are provided throughout the program. This file must be modified if the user wishes to read SDSs or Vdatas other than those in the examples. 8)'compile_ISCCP-D2like_readhdf' 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. 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 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 dumpsds [-options] - lists information about the SDSs found on the specified file hdp dumpvd [-options] - lists information about the Vdatas found on the specified file 3.4 Data Format The ISCCP-D2like-Mrg data file is written in HDF as collections of SDS(s) and Vdata(s). 3.5 Breakdown of the File Naming Convention The ISCCP-D2like-Mrg data granules adhere to the following CERES file naming convention: CER_PID_SS_PS_CC.DataDate where: CER = the CERES experiment PID = the CERES product, e.g., ISCCP-D2like-Mrg SS = the CERES sampling strategy, e.g., Terra-FM2-MODIS, as defined by the CERES experiment. For the ISCCP-D2like, this indicates the satellite and instruments that were the source of the input data into the software system that produced the ISCCP-D2like data. PS = the CERES production strategy, e.g., 'Beta2', as defined by the CERES experiment. 'BetaN' production strategies indicate versions of the product produced with algorithms that are still being validated. ISCCP-D2like data products with BetaN production strategies may only be available for a limited time and cannot be be used to publish. ISCCP-D2like data products with 'EditionN' production strategies usually indicate products that contain validated data with which the user can publish. CC = the product configuration code, e.g., '017018', 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. Multiple files that are identical in all aspects of the filename except for the 6 digit configuration code differ little, if any, scientifically. Users may, therefore, analyze data from the same sampling strategy and production strategy without regard to configuration code. For a complete history of the changes to the software, see the ISCCP-D2like product Description/Abstract document available from the URL http://eosweb.larc.nasa.gov/PRODOCS/ceres/table_ceres.html DataDate = the date of the data included in the file. For the ISCCP-D2like-Mrg, this date is in the format YYYYMM where: YYYY = the four-digit data year, MM = the two-digit month 4.0 Science Parameters Information Refer to the ISCCP-D2like-Mrg 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 both the number of SDSs and Vdatas that make up the ISCCP-D2like-Mrg product and the number of data records contained on an actual ISCCP-D2like-Mrg file are large, the sample software only demonstrates reading a limited number of SDSs for the five records included in the sample ISCCP-D2like-Mrg file. The contents of the ISCCP-D2like-Mrg record, along with a list of all the SDS(s) contained on the ISCCP-D2like-Mrg product, are described in the Data Products Catalog pages discussed in Section 3.1. A note to the user: It is recommended that before modifiying the ISCCP-D2like read program to read different ISCCP-D2like parameters, the user should first compile and run the ISCCP-D2like read program using the sample ISCCP-D2like-Mrg file as input and compare the results that are created by the read program for each SDS/parameter with the list of values for corresponding parameters in the 'CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2.dump'. If this test is successful, then the user should modify the the ISCCP-D2like read program or their own software to read the parameters in which they are interested and run that software using the Sample ISCCP-D2like as input. The values read should be compared to the values of the corresponding parameters in the sample dump file. If both of these test are successful, then the user will be ready to use their altered program with a full size ISCCP-D2like-Mrg data file. 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 HDF4.1r5. 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_ISCCP-D2like_readhdf' 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_ISCCP-D2like_readhdf A line similar to the following will be displayed: -rwxr--r-- 1 OWNER GROUP 1450 Mar 6 14:49 compile_ISCCP-D2like_readhdf 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_ISCCP-D2like_readhdf 3. Execute the script 'compile_ISCCP-D2like_readhdf' to create the executable ISCCP-D2like-Mrg_rd by typing at the command line: > source compile_ISCCP-D2like_readhdf or, on some systems, type: > compile_ISCCP-D2like_readhdf 6.2 How to Run the Sample Read Software Execute ISCCP-D2like-Mrg_rd by typing at the command line: > ISCCP-D2like-Mrg_rd CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2 7.0 Sample Output The following is the screen output generated from executing the ISCCP-D2like-Mrg_rd program with the provided sample file. Name of HDF file to be read: < CER_ISCCP-D2like-Mrg_GEO-MODIS-DAY_Sample_R5V2 ********************************************************* * Example 1: * ********************************************************* Hour Box 1 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 Hour Box 2 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 Hour Box 3 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 Hour Box 4 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 1 Hour Box 5 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 Hour Box 6 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 Hour Box 7 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 Hour Box 8 Number Of Observations - Cumulus - Monthly 3-Hourly Mean = 0 ********************************************************* * Example 2: * ********************************************************* Hour Box 1 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 Hour Box 2 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 Hour Box 3 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 Hour Box 4 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 22.728115 Hour Box 5 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 Hour Box 6 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 Hour Box 7 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 Hour Box 8 Total Cloud Fraction - Stratocumulus - Monthly 3-Hourly Mean = 340282346638528859811704183484516925440.000000 ********************************************************* * Example 3: * ********************************************************* Hour Box 1 Liquid Water Path - Stratocumulus - Monthly Mean = 18.669258 ********************************************************* * Example 4: * ********************************************************* Hour Box 1 Liquid Log Optical Depth - Altocumulus - Monthly Mean = 1.376703 ********************************************************* * Example 5: * ********************************************************* ASSOCIATEDPLATFORMSHORTNAME = Terra ********************************************************* * Example 6: * ********************************************************* NUMBEROFRECORDS = 64800