The Southern African Regional Science Initiative - SAFARI 2000 - was an international science initative aimed at developing a better understanding of the southern African earth-atmosphere-human system. The goal of SAFARI 2000 was to identify and understand the relationships between physical, chemical, biological and anthropogenic processes that underlie the biogeophysical and geogeochemical systems of southern Africa. Particular emphasis was placed upon biogenic, pyrogenic and anthropogenic emissions, including: characterization and quantification, transport and transformation in the atmosphere, influence on regional climate and meteorology, eventual deposition, and the effects of deposition on ecosystems.
This data set contains 240 files in HDF-EOS format of MISR Level 2 Top-of-Atmosphere/Cloud and Aerosol/Surface Products from the Dry Season, 2000. The area of study includes Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, and Zimbabwe in Southern Africa.
MISR (Multi-angle Imaging SpectroRadiometer) on board the TERRA (EOS AM-1) satellite views the sunlit Earth simultaneously at nine widely-spaced angles providing radiometrically and geometrically calibrated images in four spectral bands at each of the angles. These images are carefully calibrated to provide accurate measures of the brightness, contrast, and color of reflected sunlight. MISR acquires systematic multi-angle imagery for global monitoring of top-of-atmosphere and surface albedos and to measure the shortwave radiative properties of aerosols, clouds, and surface scenes in order to characterize their impact on the Earth's climate. The change in reflection at different view angles affords the means to distinguish different types of atmospheric particles (aerosols), cloud forms, and land surface covers. Combined with stereoscopic techniques, this enables construction of 3-dimensional models and more accurate estimates of the total amount of sunlight reflected by Earth's diverse environments.
The MISR Level 2 Products are geophysical measurements derived from the Level 1B2 data which consists of parameters that have been geometrically corrected and projected to a standard map grid . The products are in swaths, each derived from a single MISR orbit, where the imagery is 360 km wide and approximately 20,000 km long.
The Top-of-Atmosphere (TOA)/Cloud Products contain measurements of TOA bidirectional reflectance factors, stereoscopically-derived cloud and land (reflecting level) elevation, cloud fraction, cloud texture, and other related parameters.
The Level 2 Aerosol/Surface Product includes a range of parameters such as tropospheric aerosol optical depth; aerosol composition and size; surface directional reflectance factors and bi-hemispherical reflectance; and other related parameters.
The MISR Level 2 data provided in this data set cover the dry season of August 12 through September 28, 2000.
The MISR Path Numbers for these dates for the southern portion of Africa are 166 through 181 and applicable Block Numbers are103 through 118.
This encompasses an area bounded by latitudes 15° to 35° South and longitudes 9° to 31.5° East.
There are 240 product files in HDF-EOS format. That is 48 files for each of the five data types listed below. Each .hdf file has an associated metadata file (*.met).
Aerosol Parameters
Land Surface Parameters
Stereo Parameters
Cloud Albedo Parameters
Cloud Classifiers Parameters
More information about MISR and the Level 2 products can be found at the MISR Home Page at the NASA Jet Propulsion Laboratory (JPL): http://www-misr.jpl.nasa.gov/. Additional MISR data products and documentation are available from the NASA Langley Research Center Atmospheric Science Data Center: http://eosweb.larc.nasa.gov/PRODOCS/misr/table_misr.html.
Cite this data set as follows:
Diner, D.J. 2008. SAFARI 2000 MISR Level 2 Data, Southern Africa, Dry Season 2000. Data set. Available on-line [http://daac.ornl.gov/] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/885.
There are 240 product files in HDF-EOS format. That is 48 files for each of the five data types. Each *.hdf file has an associated metadata file (*.met).
Each .hdf file and corresponding .met file are zipped together (*.zip) for ordering convenience and a slight reduction in file size.
All 240 zipped files are contained in one directory and are sorted alphabetically by data type as follows:
MISR_AM1_AS_AEROSOL_
MISR_AM1_AS_LAND_
MISR_AM1_TC_ALBEDO_
MISR_AM1_TC_CLASSIFIERS_
MISR_AM1_TC_STEREO_
MISR File Naming Convention
Example Data File Names:
MISR_AM1_AS_AEROSOL_P166_O003538_F08_0016.b103-118.fc0cb8980.conv.zip
MISR_AM1_AS_AEROSOL_P166_O003538_F08_0016.b103-118.fc0cb8980.conv.hdf
MISR_AM1_AS_AEROSOL_P166_O003538_F08_0016.b103-118.fc0cb8980.conv.hdf.met
Data File Name Syntax:
MISR_AM1_AS_Product_Pxxx_Oxxxxxx_Fnn_nnnn.byyy-yyy.zzzzzzzzz.conv.*
where:
MISR_ = Instrument Name
AM1_ = Satellite Name
AS_ = Aerosol/Surface (AS) or
TC_ = Top-of-Atmosphere/Cloud (TC
AEROSOL_ = Level 2 Product
ALBEDO_
CLASSIFIERS_
LAND_
STEREO_
Pxxx_ = Path Number
Oxxxxxx_ = Orbit Number
Fnn_ = Format Version of the Product
nnnn = Product Version Number
.byyy-yyy = Block Number, "from - to"
.zzzzzzzzz = Characters assigned by source data center during data subsetting.
.conv = Conventional HDF-EOS Format
Example *.met Data File Records:
| Example records from MISR_AM1_AS_AEROSOL_P166_O003538_F08_0016.b103-118.fc0cb8980.conv.hdf.met GROUP = INVENTORYMETADATA GROUPTYPE = MASTERGROUP GROUP = ECSDATAGRANULE OBJECT = LOCALGRANULEID NUM_VAL = 1 VALUE ="MISR_AM1_AS_AEROSOL_P166_O003538_F08_0016.b103-118.fc0cb8980.conv.hdf" END_OBJECT = LOCALGRANULEID OBJECT = SIZEMBECSDATAGRANULE NUM_VAL = 1 VALUE = 12.4018087387085 END_OBJECT = SIZEMBECSDATAGRANULE OBJECT = PRODUCTIONDATETIME NUM_VAL = 1 VALUE = "2007-01-11T01:46:59.000Z" END_OBJECT = PRODUCTIONDATETIME NUM_VAL = 1 VALUE = "MISR_EXEC_VERSION: MISR_REFORMATTER_1.3 MISR_EXEC_NAME:misr_reformatter.cc" END_OBJECT = LOCALVERSIONID END_GROUP = ECSDATAGRANULE GROUP = PGEVERSIONCLASS OBJECT = PGEVERSION NUM_VAL = 1 VALUE = "MISR_REFORMATTER_1.3" END_OBJECT = PGEVERSION ... |
File Format Basics
The MISR Level 2 Products are stored in Hierarchical Data Format (HDF-EOS). HDF-EOS is a multi-object file format for sharing scientific data in multi-platform distributed environments. HDF-EOS files should only be accessed through the HDF-EOS library subroutine and function calls, which can be downloaded from the HDF-EOS web site [http://www.hdfeos.org/index.php]. All of the parameters are stored as Scientific Data Sets (SDS's) within the HDF file.
Detailed File Format Descriptions for MISR Data Products
The Data Products Specification (DPS) contains detailed file format descriptions of all of the various MISR data products. The DPS contains information about units, valid ranges, flag value definitions and usage of metadata. Improvements to MISR algorithmic software occasionally result in changes to file formats. While these changes most often take the form of additions, there have been cases in which field names needed to be changed. The newer DPS revisions contain tables in the front of the document stating which product version numbers are covered. Please make sure to use the Revision which corresponds to the data product version. Additional information can be found at http://eosweb.larc.nasa.gov/PRODOCS/misr/Version/.
|
Data Product and Version* * ("Fnn_nnnn"from .hdf file name) | Data Products
Specification (DPS) Files Included as Companion Fileshttp://daac.ornl.gov/daacdata/safari2k/remote_sensing/MISR/comp |
|---|---|
| Aerosol F09_0019 Land F06_0019 Stereo F08_0015 Classifiers F05_0008 Albedo F04_0008 |
DPS_v40_RevN.pdf |
| Aerosol F08_0016 Land F05_0016 Stereo F07_0012 Classifiers F04_0005 Albedo F04_0007 |
DPS_V32_RevL.pdf |
| Aerosol
F03_0007 Land F01_0007 Stereo F04_0007 |
DPS_RevE.pdf |
| Albedo
F01_0003 Classifiers F01_0001 |
DPS_v214.pdf |
MISR Reformatted Products Quality Statement
According to the MISR documentation, certain Level 2 products in the conventional HDF-EOS format may have some geolocational errors. Since we are providing Level-2 subsetted data in conventional HDF-EOS format, we are also providing the MISR quality information as a companion file (http://daac.ornl.gov/daacdata/safari2k/remote_sensing/MISR/comp/MISR_Quality_Summaries_Reformatted_Products.pdf). Additional information may be available on the MISR web site (http://eosweb.larc.nasa.gov/PRODOCS/misr/Quality_Summaries/Reformatted_Products.html).
Abdou, W. A., S. H. Pilorz, M. C. Helmlinger, et al. 2006. Sua Pan surface bidirectional reflectance: A case study to evaluate the effect of atmospheric correction on the surface products of the Multi-angle Imaging SpectroRadiometer (MISR) during SAFARI 2000. IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 44 (7): 1699-1706 Part 1.
Diner, D. J., B. H. Braswell, R. Davies, et al. 2005. The value of multiangle measurements for retrieving structurally and radiatively consistent properties of clouds, aerosols, and surfaces. REMOTE SENSING OF ENVIRONMENT 97 (4): 495-518.
Martonchik, J. V., D. J. Diner, R. Kahn, B. Gaitley, B. N. Holben. 2004. Comparison of MISR and AERONET aerosol optical depths over desert sites. GEOPHYSICAL RESEARCH LETTERS 31 (16): Art. No. L16102.
2008/06/11
2008/06/11
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