The MODIS BRDF/Albedo Product (MOD43B) provides measures of clear sky surface albedo every 16 days. Both white-sky albedo (bihemispherical reflectance) and black-sky albedo (directional hemispherical reflectance) at local solar noon are provided for 7 spectral bands and 3 broadbands. 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.
This data set provides albedo data (white-sky albedo, black-sky albedo, and albedo quality information) for for the peroid January 2002 through December 2002 at spatial resolutions of 0.25, 0.5, and 1.0 degrees latitude by longitude in standard ESRI ArcInfo ASCII GRID format in nine *.zip files.
This data set is one of the products of the International Satellite Land-Surface Climatology Project, Initiative II (ISLSCP II) data collection which contains 50 global time series data sets for the ten-year period 1986 to 1995. Selected data sets span even longer periods. A complete description of the data, their derivation, acknowledgements, and references provided by the ISLSCP II Data Management Staff is included with this data set as a companion file named 1_modis_albedo_2002_doc.pdf
ISLSCP II is a consistent collection of data sets that were compiled from existing data sources and algorithms, and were designed to satisfy the needs of modelers and investigators of the global carbon, water and energy cycle. The data were acquired from a number of U.S. and international agencies, universities, and institutions. The data and documentation have undergone two peer reviews.
ISLSCP is one of several projects of Global Energy and Water Cycle Experiment (GEWEX) [http://www.gewex.org/] and has the lead role in addressing land-atmosphere interactions -- process modeling, data retrieval algorithms, field experiment design and execution, and the development of global data sets.
Cite this data set as follows:
Strahler, A.H., C.L.B. Schaaf, and F. Gao. 2009. ISLSCP II MODIS (Collection 4) Albedo, 2002. In Hall, Forrest G., G. Collatz, B. Meeson, S. Los, E. Brown de Colstoun, and D. Landis (eds.). ISLSCP Initiative II Collection. 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/958
The archived data sets for ISLSCP II have been organized by categories. This data set is in the vegetation category--a collection of vegetation and albedo data sets.
Data Set Spatial Extent: Global gridded
Western most Longitude: -180 W
Easternmost Longitude: 180 E
Northernmost Latitude: 90N
Southernmost Latitude: -90S
Data Set Spatial Resolution: one-degree, half-degree, and quarter-degree in both latitude and longitude
Data Set Temporal Extent: January 2002 through December 2002
Data Set Temporal Resolution: Synoptic months
Data File Format
All of the data files in each data set within the ISLSCP
Initiative II data collection are in ESRI ASCII GRID format for ArcInfo.
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 columns
1 degree: 360 columns by 180 rows
1/2 degree: 720 columns by 360 rows
1/4 degree: 1440 columns by 720 rows
Within the albedo files, values for each pixel are stored as a real number. Values for albedo range between 0 and 1.
All water bodies have a fixed value of -99.0000
Missing values over land are assigned the value of -88.0000
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.
Data file naming conventions are described in the 0_modis_albedo_2002_readme.txt
These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC) [http://daac.ornl.gov].
Data Archive Contact Information:
Telephone: +1 (865) 241-3952