CERES-MISR_SSF-SSFM Readme File 1.0 Introduction The Clouds and the Earth's Radiant Energy System (CERES), the Multi-angle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) were launched into sun-synchronous polar orbit aboard NASA Terra space-platform on December 18, 1999. Two CERES instruments (FM1 and FM2) provide radiometric measurements of the Earth's atmosphere from three channels: shortwave and longwave broadband, and narrowband in window region of spectrum. The CERES instruments have 20 km resolution at nadir and scan Earth in three modes: along-track, cross-track and in rotating azimuth mode. The CERES Level 2 data product, Single Scanner Footprint (SSF), combines CERES and MODIS measurements over CERES Field-of-View (FOV) footprint. MISR measurements are designed to improve our knowledge of the Earth's environment and climate. Viewing the sunlit Earth simultaneously at nine widely-spaced angles, MISR provides radiometrically and geometrically calibrated images in four spectral bands at each of the angles. Spatial sampling of 275 and 1100 meters is provided on a global basis. This readme file provides information on the following data sets: CERES-MISR-MODIS_SSF-SSFM_Terra-FM1 CERES-MISR-MODIS_SSF-SSFM_Terra-FM2 The CERES-MISR Home page URL: http://eosweb.larc.nasa.gov/PRODOCS/ceres/level2_ceres-misr_table.html The 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 - Data set Sample Read Software 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 (provides information on the data set) The CERES-MISR_MODIS SSF-SSFM data set integrates measurements from the Clouds and the Earth's Radiant Enery System (CERES), the Multi-angle Imaging SpectroRadiometer (MISR), and the Moderate Resolution Imaging Spectroradiometer (MODIS). The MISR Level 1B2 Ellipsoid and Terrain radiances from Collections 5 and 6 are identified with CERES Terra measurements reported in the Single Scanner Footprint (SSF) Edition2B product for days the CERES instruments (FM1 and FM2) are in along-track scanning mode. The scan and packet numbers unique to the CERES footprint provide the means to match the CERES and MISR data. The resulting data granule contains 2 files: an hour of instanteous CERES SSF data which includes MODIS data and the matching CERES-MISR Single Scanner Footprint (SSFM) daytime measurements (solar zenith angle < 90 deg). The CERES Single Scanner Footprint MISR TOA Radiances (SSFM) contain one hour of instantaneous MISR Level 1B2 radiances from the Ellipsiod product (Collections 5 and 6) organized over CERES footprints (SSF Terra Edition2B) for days with CERES instruments in along-track scanning mode. The viewing angles are from the MISR Geometric Parameters product. The SSFM files contain the following HDF Scientific Data Sets (SDS): - CERES FOV Scan sample number. - CERES FOV Packet number. - Number of MISR pixels in CERES FOV. - MISR percent coverage. - Viewing zenith (9 cameras). - Relative azimuth (9 cameras). - Mean of total radiances (4 spectral bands and 9 cameras). - Stddev of total radiances (4 spectral bands and 9 cameras). MISR Spectral Bands (4) --------------------|-------------------------------------------------- Array Dimension | 1 2 3 4 Color | blue green red near-IR Wave Length | 446.4 557.5 671.7 866.4 (nanometers) MISR Cameras (9) | Aft-Viewing | Nadir | Forward-viewing --------------------|---------------------|-------|-------------------- Array Dimension | 1 2 3 4 | 5 | 6 7 8 9 Camera Name | Da Ca Ba Aa | An | Af Bf Cf Df Camera Angle | 70.5 60.0 46.6 26.1 | 00.0 | 26.1 46.6 60.0 70.5 (degrees) MISR employs nine discrete cameras pointed at fixed angles. MISR's cameras are named Df, Cf, Bf, Af, An, Aa, Ba, Ca, and Da, beginning with the most forward-viewing oblique camera and ending with the most aft-viewing oblique camera. The initial letter (A, B, C, D) denotes the focal length of the camera lens, with the A cameras having the shortest focal length and the D cameras the longest. With the exception of the A design, which is used for the nadir view as well as the near-nadir views, each letter (B, C, D) also denotes the camera angle, that is, the zenith angle of the optical axis of the camera. The small letters (f, n, a) denote whether the camera is looking forward, nadir, or aftward. Nominally, the view angles for the off-nadir A, B, C, and D cameras are 26.1, 45.6, 60.0, and 70.5 degrees, respectively, relative to a local horizontal plane at mean sea level. The CERES Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF) files contain one hour of instantaneous Clouds and the Earth's Radiant Energy System (CERES) data for a single scanner instrument. The SSF combines instantaneous CERES data with scene information from the higher-resolution imager, Moderate-Resolution Imaging Spectroradiometer (MODIS) on Terra. Scene identification and cloud properties are defined at the higher imager resolution and these data are averaged over the larger CERES footprint. The CERES-MISR SSF-SSFM files are zip files that each contain a one hour CERES SSF file and a one hour CERES SSFM file. As an example, the following zip file: CERES-MISR-MODIS_SSF-SSFM_Terra-FM1_V001.2000041221.zip will contain the following files: CER_SSFM_Terra-FM1-MODIS_Edition2B_C5_026030.2000041221 CER_SSF_Terra-FM1-MODIS_Edition2B_026030.2000041221 For CERES SSF files, please refer to the following documentation: SSF Description Abstract - http://eosweb.larc.nasa.gov/GUIDE/dataset_documents/cer_ssf.html SSF Collection Guide - http://ceres.larc.nasa.gov/collect_guide.php 2.1 Data Quality The CERES SSF Terra Edition2B Data Quality Summary: http://eosweb.larc.nasa.gov/PRODOCS/ceres/SSF/Quality_Summaries/CER_SSF_Terra_Edition2B.html The data quality of the original MISR data used as input to the CERES SSFM file may be obtained from the MISR Quality Statements http://eosweb.larc.nasa.gov/PRODOCS/misr/Quality_Summaries/misr_qual_stmts.html 2.2 Science Representatives If you have any questions concerning the data, please contact the Atmospheric Science Data Center User and Data 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, Virginia 23681-2199 E-mail: b.a.wielicki@nasa.gov FAX: (757) 864-7996 Phone: (757) 864-5683 2. Dr. Norman Loeb, ADM Working Group chair NASA Langley Research Center Mail Stop 420 Hampton, Virginia 23681-2199 E-mail: normal.g.loeb@nasa.gov FAX: (757) 864-7996 Phone: (757) 864-5688 3.0 Format and Packaging 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.info-zip.org/pub/infozip/ The SSF and SSFM files are collections of data in HDF Scientific Data Sets (SDSs). The NCSA HDF information, documentation, tutorials, libraries, etc., can be found at the following URL: http://hdf.ncsa.uiuc.edu/ 3.1 Breakdown of the File Naming Convention 3.1.1 CERES SSF-SSFM zip file The SSF-SSFM data granules adhere to the following file naming convention: FUS_PID_SS_PS.DataDate e.g., 'CERES-MISR-MODIS_SSF-SSFM_Terra-FM1_V001.2000041221.zip' where: FUS = the fusion of CERES, MISR, and MODIS data, e.g., 'CERES-MISR-MODIS' PID = the CERES product, e.g., 'SSF-SSFM' SS = the CERES sampling strategy, e.g., 'Terra-FM1'. This indicates the satellite and instrument that were the source of the input to the CERES data SSF data. PS = the version number, e.g., 'V001' 'V001' contains SSF Edition2B and SSFM Collection 5 or 6 data. DataDate = the date of the data included in the file. For the SSF and SSFM, 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) 3.1.2 CERES SSF and SSFM data file The SSF and SSFM data granules adhere to the following CERES file naming convention: CER_PID_SS_PS_CC.DataDate e.g., SSF file, 'CER_SSF_Terra-FM1-MODIS_Edition2B_026030.2000041221' e.g., SSFM file, 'CER_SSFM_Terra-FM1-MODIS_Edition2B_C5_026030.2000041221' where: CER = the CERES experiment PID = the CERES product, e.g., SSF or SSFM SS = the CERES sampling strategy, e.g., 'Terra-FM1-MODIS', as defined by the CERES experiment. For the SSF, this indicates the satellite and instruments that were the source of the input data into the software system that produced the SSF data. For the SSFM, this convention was repeated to match SSF and SSFM file names. PS = the CERES production strategy, e.g., 'Edition2B' for SSF data products indicate products contain validated data with which the user can publish. The SSFM data products contain the SSF 'Edition2B' production strategy and the MISR Collection number 'C5' for Collection 5 or 'C6' for Collection 6, e.g., 'Edition2B_C5'. CC = the product configuration code, e.g., '026030', 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 SSF 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 SSF and SSFM, 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 4.1 For the CERES SSF files, please refer to the SSF Collection Guide: http://ceres.larc.nasa.gov/collect_guide.php 4.2 For the CERES SSFM files, the following Scientific Data Set (SDS) information is also contained in the metadata associated with each SDS. SDS# SDS Name / Attributes ---- --------------------------------------- 0 Scan sample number Dimensions => 1 [ 45605] Dimension 1 => Footprints Data Type => INT DFNT_INT16 Units => Unitless Valid Range => 1 660 Fill Value => 32767 _______________________________________ 1 Packet number Dimensions => 1 [ 45605] Dimension 1 => Footprints Data Type => INT DFNT_INT16 Units => Unitless Valid Range => 0 13100 Fill Value => 32767 _______________________________________ 2 Number of MISR pixels in CERES FOV Dimensions => 2 [ 9, 45605] Dimension 1 => Footprints Data Type => LONG DFNT_INT32 Units => Unitless Valid Range => 1 100000 Fill Value => 2147483647 _______________________________________ 3 MISR percent coverage Dimensions => 2 [ 9, 45605] Dimension 1 => MISR Camera Dimension 2 => Footprints Data Type => FLOAT DFNT_FLOAT32 Units => Percent Valid Range => 0.0000000 100.0000 Fill Value => 3.402823E+038 _______________________________________ 4 Viewing zenith Dimensions => 2 [ 9, 45605] Dimension 1 => MISR Camera Dimension 2 => Footprints Data Type => FLOAT DFNT_FLOAT32 Units => Degree Valid Range => -90.00000 90.00000 Fill Value => 3.402823E+038 _______________________________________ 5 Relative azimuth Dimensions => 2 [ 9, 45605] Dimension 1 => MISR Camera Dimension 2 => Footprints Data Type => FLOAT DFNT_FLOAT32 Units => Degree Valid Range => 0.0000000 360.0000 Fill Value => 3.402823E+038 _______________________________________ 6 Mean of total radiances Dimensions => 3 [ 9, 4, 45605] Dimension 1 => MISR Camera Dimension 2 => Specral Band Dimension 3 => Footprints Data Type => FLOAT DFNT_FLOAT32 Units => W m-2 sr-1 micron-1 Valid Range => 0.0000000 1000.000 Fill Value => 3.402823E+038 _______________________________________ 7 Stddev of total radiances Dimensions => 3 [ 9, 4, 45605] Dimension 1 => MISR Camera Dimension 2 => Specral Band Dimension 3 => Footprints Data Type => FLOAT DFNT_FLOAT32 Units => W m-2 sr-1 micron-1 Valid Range => 0.0000000 1000.000 Fill Value => 3.402823E+038 _______________________________________ 5.0 Data set Sample Read Software To read the files, a sample read software package written in C is provided. Information about downloading and using this software is available at the following URL: http://eosweb.larc.nasa.gov/PRODOCS/ceres/readme/readme_cer_ssfm_SampleRead_R4-555.txt http://eosweb.larc.nasa.gov/PRODOCS/ceres/read_software/cer_ssfm_SampleRead_R4-555.zip Updated: Sep 26, 2012 Feb 27, 2006