CERES CRS R3-564 Readme File 1.0 Introduction This readme file document provides information on the following Clouds and Earth's Radiant Energy System (CERES) CRS data sets: Aqua: CER_CRS_Aqua-FM3_Edition2A CER_CRS_Aqua-FM4_Edition2A CER_CRS_Aqua-FM3_Beta1 CER_CRS_Aqua_FM4_Beta1 Terra CER_CRS_Terra_FM1_Edition2B CER_CRS_Terra_FM2_Edition2B 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 2 South Wright Street NASA Langley Research Center Hampton, Virginia 23681-2199 U.S.A. E-mail: larc@eos.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 CRS data sets, please refer to the corresponding Quality Summary Document available from the URL http://eosweb.larc.nasa.gov/PRODOCS/ceres/table_ceres.html. 2.3 Other pertinent information The CERES CRS product is produced from software maintained by the CERES Inversion Data Management Team. 2.4 Science Representatives *NOTE TO USER: If you have any questions concerning the sample code or the data, please contact the Atmospheric Science Data Center User Services Office. The contact information is provided above in Section 1.0. 1. Dr. Bruce A. Wielicki, CERES Interdisciplinary Principal Investigator NASA Langley Research Center Mail Stop 420 Hampton, VA 23681-2199 E-mail: Bruce.A.Wielicki@nasa.gov FAX: (757)864-7996 Phone: (757)864-5683 2. Dr. Patrick Minnis, Clouds Working Group chair NASA Langley Research Center Mail Stop 420 Hampton, VA 23681-2199 E-mail: P.Minnis@nasa.gov FAX: (757)864-7996 Phone: (757)864-5671 3. Dr. Norman Loeb, ADM Working Group chair NASA Langley Research Center Mail Stop 420 Hampton, VA 23681-2199 E-mail: N.G.Loeb@larc.nasa.gov FAX: (757)864-7996 Phone: (757)864-5688 4. Dr. David Kratz, Surface-only Working Group chair NASA Langley Research Center Mail Stop 420 Hampton, VA 23681-2199 E-mail: David.P.Kratz@nasa.gov FAX: (757)864-7996 Phone: (757)864-5669 3.0 Format and Packaging This package includes a program, written in C, which will read an CRS HDF file. The examples provided in the main (CRS_readhdf.c) program are written specifically for SDS(s) and Vdata(s) in CRS files. This read program is provided as a template to the user who will need to modify it, if they need to read different CRS parameters. Information on the structure of the CRS 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_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.dump. Complete parameter descriptions are available in the Collection/User's Guide, which is on-line at URL: http://asd-www.larc.nasa.gov/ceres/collect_guide. 3.1 Sample Read Package Contents This package consists of the following files: 1) CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101 2) CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.dump 3) CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.met 4) CRS_HDFread.h 5) CRS_readHDFfuncs.c 6) CRS_readhdf.c 7) compile_CRS_readhdf Descriptions for each file is as follows: 1)'CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101' is a sample 5-footprint CRS file which is used by the examples in 'CRS_readhdf.c' 2)'CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.dump' is an ASCII file containing a description of the data in the sample CRS, 'CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101'. If a value in the CRS 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_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.dump' file includes a list of ALL the data on the 5 footprint sample CRS (250 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. 3)CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.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 CRS HDF data file. An example of a metadata parameter found in the metadata file and on the CRS HDF file is LOCALGRANULEID, which has a value set to the original granule file name. 4)'CRS_HDFread.h' is a header file for 'CRS_readhdf.c' and the CRS HDF read functions. 5)'CRS_readHDFfuncs.c' is a file consisting of C functions that are linked with 'CRS_readhdf.c' and call the HDF functions. 6)'CRS_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 CRS 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. 7)'compile_CRS_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 CRS data files are written in HDF as collections of SDS(s) and Vdata(s). 3.5 Breakdown of the File Naming Convention The CRS 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., CRS SS = the CERES sampling strategy, e.g., Terra-FM2-MODIS, as defined by the CERES experiment. For the CRS, this indicates the satellite and instruments that were the source of the input data into the software system that produced the CRS 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. CRS data products with BetaN production strategies may only be available for a limited time and cannot be be used to publish. CRS 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 CRS 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 CRS, this date is in the format YYYYMMDDHH where: YYYY = the four-digit data year, MM = the two-digit month DD = the two-digit day HH = the two-digit hour (00-23) 4.0 Science Parameters Information Refer to the CRS 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 CRS product and the number of data records contained on an actual CRS file are large, the sample software only demonstrates reading a limited number of SDSs for the five footprints included in the sample CRS file. The contents of the CRS footprint, along with a list of all the SDS(s) contained on the CRS 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 CRS read program to read different CRS parameters, the user should first compile and run the CRS read program using the sample CRS 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 CRS sample dump file, 'CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101.dump'. If this test is successful, then the user should modify the the CRS read program or their own software to read the parameters in which they are interested and run that software using the Sample CRS 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 CRS 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_CRS_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_CRS_readhdf A line similar to the following will be displayed: -rwxr--r-- 1 OWNER GROUP 1450 Mar 6 14:49 compile_CRS_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_CRS_readhdf 3. Execute the script 'compile_CRS_readhdf' to create the executable crs_rd by typing at the command line: > source compile_CRS_readhdf or, on some systems, type: > compile_CRS_readhdf 6.2 How to Run the Sample Read Software Execute crs_rd by typing at the command line: > crs_rd CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101 7.0 Sample Output The following is the screen output generated from executing the crs_rd program with the provided sample file. > ./crs_rd CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101 Name of HDF file to be read: < CER_CRS_Terra-FM2-MODIS_Sample_000000.2001100101 ********************************************************* * Example 1: * ********************************************************* Footprint 1 Photosynthetically active radiation over surface = 73.684990 Footprint 2 Photosynthetically active radiation over surface = 115.411194 Footprint 3 Photosynthetically active radiation over surface = 119.516678 Footprint 4 Photosynthetically active radiation over surface = 123.762253 Footprint 5 Photosynthetically active radiation over surface = 129.438751 ********************************************************* * Example 2: * ********************************************************* Footprint 1 Aerosol constituency flags(1) = 24016030 Aerosol constituency flags(2) = 25006010 Aerosol constituency flags(3) = 18847036 Aerosol constituency flags(4) = 1000005 Aerosol constituency flags(5) = 11022035 Aerosol constituency flags(6) = 10100038 Aerosol constituency flags(7) = 9000038 Footprint 2 Aerosol constituency flags(1) = 24016030 Aerosol constituency flags(2) = 25006010 Aerosol constituency flags(3) = 18847036 Aerosol constituency flags(4) = 1000005 Aerosol constituency flags(5) = 11022035 Aerosol constituency flags(6) = 10100038 Aerosol constituency flags(7) = 9000038 Footprint 3 Aerosol constituency flags(1) = 24023030 Aerosol constituency flags(2) = 25008010 Aerosol constituency flags(3) = 18805036 Aerosol constituency flags(4) = 1000005 Aerosol constituency flags(5) = 11028035 Aerosol constituency flags(6) = 10126038 Aerosol constituency flags(7) = 9000038 Footprint 4 Aerosol constituency flags(1) = 24023030 Aerosol constituency flags(2) = 25008010 Aerosol constituency flags(3) = 18805036 Aerosol constituency flags(4) = 1000005 Aerosol constituency flags(5) = 11028035 Aerosol constituency flags(6) = 10126038 Aerosol constituency flags(7) = 9000038 Footprint 5 Aerosol constituency flags(1) = 24023030 Aerosol constituency flags(2) = 25008010 Aerosol constituency flags(3) = 18805036 Aerosol constituency flags(4) = 1000005 Aerosol constituency flags(5) = 11028035 Aerosol constituency flags(6) = 10126038 Aerosol constituency flags(7) = 9000038 ********************************************************* * Example 3: * ********************************************************* Footprint 1 Percentiles of visible optical depth for cloud layer Percentile 1 for Lower Layer = 3.090291 Percentile 1 for Upper Layer = 0.607926 Percentile 2 for Lower Layer = 3.090291 Percentile 2 for Upper Layer = 0.623101 Percentile 3 for Lower Layer = 3.090291 Percentile 3 for Upper Layer = 0.665449 Percentile 4 for Lower Layer = 3.160731 Percentile 4 for Upper Layer = 0.738107 Percentile 5 for Lower Layer = 3.160731 Percentile 5 for Upper Layer = 0.798151 Percentile 6 for Lower Layer = 3.323212 Percentile 6 for Upper Layer = 0.840746 Percentile 7 for Lower Layer = 3.323212 Percentile 7 for Upper Layer = 0.865967 Percentile 8 for Lower Layer = 3.669725 Percentile 8 for Upper Layer = 0.886713 Percentile 9 for Lower Layer = 3.702814 Percentile 9 for Upper Layer = 0.913339 Percentile 10 for Lower Layer = 3.702814 Percentile 10 for Upper Layer = 0.967665 Percentile 11 for Lower Layer = 3.827324 Percentile 11 for Upper Layer = 1.172163 Percentile 12 for Lower Layer = 3.827324 Percentile 12 for Upper Layer = 1.194814 Percentile 13 for Lower Layer = 3.827324 Percentile 13 for Upper Layer = 1.257099 Footprint 2 Percentiles of visible optical depth for cloud layer Percentile 1 for Lower Layer = 3.160731 Percentile 1 for Upper Layer = 0.424145 Percentile 2 for Lower Layer = 3.160731 Percentile 2 for Upper Layer = 0.584905 Percentile 3 for Lower Layer = 3.160731 Percentile 3 for Upper Layer = 0.632624 Percentile 4 for Lower Layer = 3.160731 Percentile 4 for Upper Layer = 0.675495 Percentile 5 for Lower Layer = 3.168009 Percentile 5 for Upper Layer = 0.738107 Percentile 6 for Lower Layer = 3.168009 Percentile 6 for Upper Layer = 0.795196 Percentile 7 for Lower Layer = 3.315473 Percentile 7 for Upper Layer = 0.822367 Percentile 8 for Lower Layer = 3.315473 Percentile 8 for Upper Layer = 0.857506 Percentile 9 for Lower Layer = 3.669725 Percentile 9 for Upper Layer = 0.899631 Percentile 10 for Lower Layer = 3.669725 Percentile 10 for Upper Layer = 0.967370 Percentile 11 for Lower Layer = 3.827324 Percentile 11 for Upper Layer = 1.118129 Percentile 12 for Lower Layer = 3.827324 Percentile 12 for Upper Layer = 1.192195 Percentile 13 for Lower Layer = 3.827324 Percentile 13 for Upper Layer = 1.257099 Footprint 3 Percentiles of visible optical depth for cloud layer Percentile 1 for Lower Layer = 0.489349 Percentile 1 for Upper Layer = 0.424145 Percentile 2 for Lower Layer = 0.489349 Percentile 2 for Upper Layer = 0.505649 Percentile 3 for Lower Layer = 0.508105 Percentile 3 for Upper Layer = 0.541235 Percentile 4 for Lower Layer = 0.515958 Percentile 4 for Upper Layer = 0.588517 Percentile 5 for Lower Layer = 0.519933 Percentile 5 for Upper Layer = 0.636103 Percentile 6 for Lower Layer = 0.578260 Percentile 6 for Upper Layer = 0.677702 Percentile 7 for Lower Layer = 0.579179 Percentile 7 for Upper Layer = 0.733393 Percentile 8 for Lower Layer = 0.597049 Percentile 8 for Upper Layer = 0.790235 Percentile 9 for Lower Layer = 0.612633 Percentile 9 for Upper Layer = 0.832468 Percentile 10 for Lower Layer = 0.619928 Percentile 10 for Upper Layer = 0.892121 Percentile 11 for Lower Layer = 0.668977 Percentile 11 for Upper Layer = 1.124277 Percentile 12 for Lower Layer = 0.679953 Percentile 12 for Upper Layer = 1.225360 Percentile 13 for Lower Layer = 0.679953 Percentile 13 for Upper Layer = 3.669725 Footprint 4 Percentiles of visible optical depth for cloud layer Percentile 1 for Lower Layer = 0.468898 Percentile 1 for Upper Layer = 0.424145 Percentile 2 for Lower Layer = 0.489349 Percentile 2 for Upper Layer = 0.426124 Percentile 3 for Lower Layer = 0.494110 Percentile 3 for Upper Layer = 0.505649 Percentile 4 for Lower Layer = 0.510434 Percentile 4 for Upper Layer = 0.548802 Percentile 5 for Lower Layer = 0.519933 Percentile 5 for Upper Layer = 0.579436 Percentile 6 for Lower Layer = 0.536402 Percentile 6 for Upper Layer = 0.623109 Percentile 7 for Lower Layer = 0.565042 Percentile 7 for Upper Layer = 0.646220 Percentile 8 for Lower Layer = 0.579179 Percentile 8 for Upper Layer = 0.681160 Percentile 9 for Lower Layer = 0.597049 Percentile 9 for Upper Layer = 0.718963 Percentile 10 for Lower Layer = 0.601603 Percentile 10 for Upper Layer = 0.790235 Percentile 11 for Lower Layer = 0.619928 Percentile 11 for Upper Layer = 0.857290 Percentile 12 for Lower Layer = 0.668977 Percentile 12 for Upper Layer = 0.928477 Percentile 13 for Lower Layer = 0.679953 Percentile 13 for Upper Layer = 0.980604 Footprint 5 Percentiles of visible optical depth for cloud layer Percentile 1 for Lower Layer = 0.408507 Percentile 1 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 2 for Lower Layer = 0.468898 Percentile 2 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 3 for Lower Layer = 0.494110 Percentile 3 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 4 for Lower Layer = 0.515958 Percentile 4 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 5 for Lower Layer = 0.536402 Percentile 5 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 6 for Lower Layer = 0.571457 Percentile 6 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 7 for Lower Layer = 0.586729 Percentile 7 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 8 for Lower Layer = 0.608916 Percentile 8 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 9 for Lower Layer = 0.629334 Percentile 9 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 10 for Lower Layer = 0.658407 Percentile 10 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 11 for Lower Layer = 0.720721 Percentile 11 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 12 for Lower Layer = 0.761722 Percentile 12 for Upper Layer = 340282346638528860000000000000000000000.000000 Percentile 13 for Lower Layer = 0.801018 Percentile 13 for Upper Layer = 340282346638528860000000000000000000000.000000 ********************************************************* * Example 4: * ********************************************************* Central wavelengths of imager channels 1. 0.469000 2. 0.555000 3. 0.645000 4. 0.858000 5. 0.905000 6. 1.240000 7. 1.375000 8. 1.640000 9. 2.130000 10. 3.792000 11. 4.050000 12. 6.720000 13. 8.550000 14. 11.030000 15. 12.020000 16. 13.340000 17. 13.640000 18. 13.940000 19. 14.240000 20. 0.000000 ********************************************************* * Example 5: * ********************************************************* ASSOCIATEDPLATFORMSHORTNAME = Terra ********************************************************* * Example 6: * ********************************************************* NUMFOV = 5 8.0 Additional Information Regarding CERES CRS Data Last Updated: May 31, 2007 -----------------------------------------------------------------------------