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ISLSCP Initiative II Home General Data Overview Vegetation Data Overview |
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ISLSCP Initiative II |
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Vegetation Data
The MODIS BRDF/Albedo Product provides coarse resolution 16-day multi-spectral and broadband albedos for a full year of MODerate resolution Imaging Spectroradiometer (MODIS) data (2002), along with quality information for each data set. Both white-sky albedo (bi-hemispherical reflectance) and black-sky albedo (directional hemispherical reflectance) at local solar noon are provided for 7 spectral bands and 3 broadbands (see below). Since black-sky albedo represents the direct beam contribution while white-sky represents the completely diffuse contribution, these measures can be linearly combined as a function of the fraction of diffuse skylight (itself a function of optical depth) to provide an actual or instantaneous albedo at local solar noon.
Data Provider: Alan H. Strahler, Crystal L.B. Schaaf, Feng Gao
 Data Files (ISLSCP II Disc #1) |
 Data Set Documentation |
 Image Viewing Tutorial |
All of the files in the ISLSCP Initiative II data collection are in the ASCII, or text format. The file format consists of numerical fields of varying length, which are delimited by a single space and arranged in columns and rows. The files at different spatial resolutions each contain the following numbers of column and rows:
One degree: 360 columns by 180 rows
1/2 degree: 720 columns by 360 rows
1/4 degree: 1440 columns by 720 rows
The albedo files are stored with each pixel as real number. Values are albedo between 0 and 1. All water bodies have a fixed value of -99, and regions with no data over land are filled as -88. All files are gridded to a common equal-angle lat/long grid, where the coordinates of the upper left corner of the files are located at 180°W, 90°N and the lower right corner coordinates are located at 180°E, 90°S. Data in the files are ordered from North to South and from West to East beginning at 180 degrees West and 90 degrees North. The data files are PKZip compressed.
The data files fall into the following categories:
| Black Sky Albedo (BSA) | Surface black-sky albedo at local solar noon derived from MODIS multidate surface reflectances in bands 1-7 and 3 broadbands. Albedo is the fraction of incident solar radiation that a surface reflects -- in this case a direct beam solar illumination condition. |
| White Sky Albedo (WSA) | White sky albedo under entirely diffuse solar illumination conditions for MODIS bands 1-7 and 3 broadbands |
| Albedo Quality Information (QA) | Eight layers of Albedo QA associated with MODIS Albedo products. |
Related Pages:
ISLSCP Initiative II Home
General Data Overview
Vegetation Data Overview
MODIS Albedo from 2002
Revision Date: April 25, 2007