L ISCCP_ICESNOW_NAT Data Set Readme File 1.0 Introduction This file contain information about the International Satellite Cloud Climatology Project (ISCCP) Ice Snow (ICESNOW) native (NAT) data set. (ISCCP_ICESNOW_NAT) The data files are in native format. The home page for ISCCP is located at http://isccp.giss.nasa.gov/ This readme file includes the following sections: Section 2.0 - provides general information about the data set. Section 3.0 - describes the format of the data. Section 4.0 - provides the user with science parameter information Section 5.0 - describes the sample read software. Section 6.0 - discusses how to invoke the run-time executable. Section 7.0 - provides an example of an actual run of the sample read software. If users have question while using the ISCCP_ICESNOW_NAT sample read software, please contact the Langley Data Center User and Data Services office at: Langley Atmospheric Science Data Center User and Data Services Office NASA Langley Research Center Mail Stop 157D 2 South Wright Street Hampton, VA 23681-2199 U.S.A. Email: support-asdc@earthdata.nasa.gov Phone: (757) 864-8656 FAX: (757) 864-8807 URL: http://eosweb.larc.nasa.gov 2.0 Data Set Description Documentation on the ISCCP_ICESNOW_NAT data set is contained within the DX/D1/D2 New Cloud Data Documentation which can be obtained from the following URL: http://isccp.giss.nasa.gov/documents.html Contact for scientific inquiries: Dr. William B. Rossow NASA Goddard Institute for Space Studies 2880 Broadway New York, NY 10025 email: clwbr@giss.nasa.gov Phone: 212-678-5567 FAX: 212-678-5662 Contact for technical assistance: Violeta Golea NASA Goddard Institute for Space Studies 2880 Broadway New York, NY 10025 email: vgolea@giss.nasa.gov 3.0 Format and Packaging Each file of ISCCP_ICESNOW_NAT data is a zipped file containing a years worth of ISCCP_ICESNOW_NAT data. To read the files, first unzip them with Info_Zip software. Information about downloading and using this freeware is available at the following URL: http://www.cdrom.com/pub/infozip/ The data files are named in the following manner: is_YYMMDD_YYMMDD.XX . The first YYMMDD is the beginning date for this set of data files, the second YYMMDD is the end date for this set of data files. The XX is the number of the file, which specifies the contents of the file. Specifically the files are: is_YYMMDD_YYMMDD.01 - description of the files. is_YYMMDD_YYMMDD.02 - a table of contents is_YYMMDD_YYMMDD.03 - the fortran program supplied with the data files is_YYMMDD_YYMMDD.04 - the ancillary file for the whole year is_YYMMDD_YYMMDD.05 and beyond are the data files. 4.0 Science Parameters Information The ISCCP_ICESNOW_NAT data set is a merged product containing separate snow and sea ice data sets. The values given are fractional coverage for 5-day intervals. The data are collected on a global equal-area grid with the cell area equivalent to 1 deg. latitude/longitude at the equator. The grid begins at the South Pole with the intersection of the Greenwich meridian (0 deg. longitude) and the South Pole as a cell corner. For a description of this product and its specific parameters, the reader is referred to the document "International Satellite Cloud Climatology Project (ISCCP) Documentation of New Cloud Datasets" available from the URL http://isccp.giss.nasa.gov/documents.html. 5.0 Description of Sample Read Software The read program was developed in the "C" language from the Fortran sample read software provided by the data provider - NASA Goddard Institute for Space Studies (GISS). The user will be prompted for input and output filenames. 6.0 Implementing Sample Read Software The sample read software has been tested on the "Sun4", the "HP" UNIX based workstation and a "SGI" based system. There are no library routines that need to be loaded or linked. 6.1 How to Compile the Sample Read Software To compile the sample read sofware, at the command line type: cc -o read_is_c isccp_icesnow_read.c 6.2 How to Run the Sample Read Software To invoke the executable file: at the command line type: read_is_c Section: 7.0 A Sample Run The following sample run shows the ice/snow values for a specified latitude band. ********************************************************************* * * * Langley DAAC * * PROJECT_LEVEL/DATA_SET_LEVEL READ SOFTWARE * * VERSION NUMBER: * * Language: C * * Platforms supported: SUN * * HP * * SGI * * Solaris 2.3 * * Contact: Langley DAAC user and Data Services Office * * NASA Langley Research Center * * Mail Stop 157D * * Hampton, VA 23681-0001 * * PHONE: (757)864-8656 FAX: (757)864-8807 * * * ********************************************************************* Enter 'c' to view the ice and snow values for a specified latitude band. Enter 's' to view a square map of the ice and snow values for a specified latitude and longitude region. Enter 'h' to receive help with commands. Enter 'x' to exit or terminate processing. c Enter ancillary filename:is_940101_941227.04 Ancillary data file is is_940101_941227.04 Read software will process data files until you wish to stop. Press 'Y' or 'y' to continue or 'x' to stop. y Enter data file to be used: is_940101_941227.06 Enter a name for the output file: is_out Opened data file: is_940101_941227.06 Enter desired latitude band: (Value should be between 1 -> 180; Latitude bands are in 1 degree increments, starting at the South Pole.) 1 Number of full boxes in data file: 20940 out of 41252 Do you wish to process another data file? n PROGRAM HAS ENDED 7.1 Output file The data file used is is_940101_941227.06 IS PREFIX INFORMATION: DATE: YEAR 94 MONTH 1 DAY 6 SEAICE: SOURCE SSMI NORTH: YEAR 94 MONTH 1 DAY 4 TO YEAR 94 MONTH 1 DAY 8 SOUTH: YEAR 94 MONTH 1 DAY 4 TO YEAR 94 MONTH 1 DAY 8 SNOW: SOURCE NOAA YEAR 94 MONTH 1 DAY 6 ******************************************************* processing equal-area lon/lat 1 1 CENTER: CENTER LON/LAT 60.00 -89.50 Ice Snow Cover code value: 70 Land Cover percent value : 100 ******************************************************* processing equal-area lon/lat 2 1 CENTER: CENTER LON/LAT 180.00 -89.50 Ice Snow Cover code value: 70 Land Cover percent value : 100 ******************************************************* processing equal-area lon/lat 3 1 CENTER: CENTER LON/LAT 300.00 -89.50 Ice Snow Cover code value: 70 Land Cover percent value : 100 7.2 Another sample run The following sample run show the ice/snow values on an equal-area grid for a specified latitude band. ********************************************************************* * * * Langley DAAC * * PROJECT_LEVEL/DATA_SET_LEVEL READ SOFTWARE * * VERSION NUMBER: * * Language: C * * Platforms supported: SUN * * HP * * SGI * * Solaris 2.3 * * Contact: Langley DAAC user and Data Services Office * * NASA Langley Research Center * * Mail Stop 157D * * Hampton, VA 23681-0001 * * PHONE: (757)864-8656 FAX: (757)864-8807 * * * ********************************************************************* Enter 'c' to view the ice and snow values for a specified latitude band. Enter 's' to view a square map of the ice and snow values for a specified latitude and longitude region. Enter 'h' to receive help with commands. Enter 'x' to exit or terminate processing. s Enter ancillary filename:is_940101_941227.04 Ancillary data file is is_940101_941227.04 Read software will process data files until you wish to stop. Press 'Y' or 'y' to continue or 'x' to stop. y Enter data file to be used: is_940101_941227.06 Enter a name for the output file: is_out1 Opened data file: is_940101_941227.06 Number of full boxes in data file: 20940 out of 41252 For Ice/Snow codes enter : I For Land Cover values enter : L For Both enter : B b For readability, ranges should be kept small; i.e., 0 to 10. Latitude bands are in 1 degree increments starting at the South Pole; longitude bands are 1 degree increments starting at the Greenwich meridian. Enter beginning longitude band:(1-360 degrees) 1 Enter ending longitude band:(1-360 degrees) 10 Enter beginning latitude band:(1-180 degrees) 1 Enter ending latitude band:(1-180 degrees) 1 Do you wish to process another data file? n PROGRAM HAS ENDED 7.3 Output from run The data file used is is_940101_941227.06 IS PREFIX INFORMATION: DATE: YEAR 94 MONTH 1 DAY 6 SEAICE: SOURCE SSMI NORTH: YEAR 94 MONTH 1 DAY 4 TO YEAR 94 MONTH 1 DAY 8 SOUTH: YEAR 94 MONTH 1 DAY 4 TO YEAR 94 MONTH 1 DAY 8 SNOW: SOURCE NOAA YEAR 94 MONTH 1 DAY 6 Ice/Snow Cover codes latitude /longitude index numbers 1 2 3 4 5 6 7 8 9 10 ---------------------------------------------------------------------- 1 | 70 70 70 70 70 70 70 70 70 70 Land Cover fraction values latitude /longitude index numbers 1 2 3 4 5 6 7 8 9 10 ---------------------------------------------------------------------- 1 | 100 100 100 100 100 100 100 100 100 100 Last updated: February 29, 2000 April 30, 2009