The MCD43D40 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) QA Snow Status dataset is produced daily using 16 days of Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) data at 30 arc second (1,000 meter (m)) resolution. Data are temporally weighted to the ninth day which is reflected in the Julian date in the file name. This Climate Modeling Grid (CMG) product covers the entire globe for use in climate simulation models. Due to the large file size, each MCD43D project contains just one data layer. MCD43D40 provides snow cover information for the MCD43D products.
MCD43D40 contains the snow status quality layer which identifies each pixel as either “Snow-free Albedo Retrieved” or “Snow Albedo Retrieved” for the acquisition period.
The MODIS BRDF/Albedo products have achieved stage 3 validation.
|File Size||~17 MB|
|Temporal Extent||2000-02-16 to Present|
|Coordinate System||Geographic Latitude and Longitude|
|Number of Science Dataset (SDS) Layers||1|
|Columns/Rows||43200 x 21600|
|Pixel Size||~1000 m|
|SDS Name||Description||Units||Data Type||Fill Value||No Data Value||Valid Range||Scale Factor||Additional Offset|
|Global_Snow_Status||Snow-free or snow BRDF/Albedo retrieved||N/A||8-bit unsigned integer||255||N/A||0 to 254||N/A||N/A|
|0||Snow-free Albedo Retrieved|
|1||Snow Albedo Retrieved|
The quality layer is stored in an efficient bit-encoded manner. The unpack_sds_bits executable from the LDOPE Tools is available to the user community to help parse and interpret this layer.
For complete information about MCD43D40 known issues refer to the MODIS Land Quality Assessment website.