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Description
The MOD09A1 Version 6 data product was decommissioned on July 31, 2023. Users are encouraged to use the MOD09A1 Version 6.1 data product.
The Moderate Resolution Imaging Spectroradiometer (MODIS) Terra MOD09A1 Version 6 product provides an estimate of the surface spectral reflectance of Terra MODIS Bands 1 through 7 corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Along with the seven 500 meter (m) reflectance bands are two quality layers and four observation bands. For each pixel, a value is selected from all the acquisitions within the 8-day composite period. The criteria for the pixel choice include cloud and solar zenith. When several acquisitions meet the criteria the pixel with the minimum channel 3 (blue) value is used.
Known Issues
Striping due to a dead detector is noticeable for bands 5, 6, and 7 in scenes acquired February 24 through October 31, 2000. Corrections were implemented to reduce the striping in data acquired after November 1, 2000. Users should always check the band quality for dead detectors even though reflectance values may be in the valid range.
The Collection 6 MODIS Land Surface Reflectance product (MOD09) may incorrectly flag retrievals as ‘High Aerosol’ over brighter surfaces and at higher view angles. This will impact the downstream MODIS BRDF/Albedo (MCD43) and Vegetation Index (MOD13 and MYD13) data products which use the aerosol quantity flag to screen out high aerosol values.
Corrections were implemented in Collection 6.1 reprocessing.
The following changes and improvements were implemented for inputs to MODIS Version 6 terra surface reflectance data products: (1) Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables, (2) Refinements to the internal snow, cloud, and cloud shadow detection algorithms. Uses Bidirectional Reflectance Distribution Function (BRDF) database to better constrain the different threshold used, (3) Processes ocean bands to create a new Surface Reflectance Ocean product and provides Quality Assurance (QA) datasets for these bands, and (4) Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.
Land Processes Distributed Active Archive Center (LP DAAC)
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MODIS Adaptive Processing System, Terrestrial Information Systems Laboratory, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA (NASA/GSFC/SED/ESD/TISL/MODAPS)
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
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Citation Copied
Vermote, E. (2015). MOD09A1 MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V006 [Data set]. NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/MODIS/MOD09A1.006 Date Accessed: 2026-06-04
Vermote, Eric. “MOD09A1 MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V006.” NASA Land Processes Distributed Active Archive Center, 2015. doi:10.5067/MODIS/MOD09A1.006. Date Accessed: 2026-06-04
Vermote, Eric. MOD09A1 MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V006. NASA Land Processes Distributed Active Archive Center, 2015, doi:10.5067/MODIS/MOD09A1.006. Date Accessed: 2026-06-04
File Naming Convention
MOD09A1.A2002273.h29v03.006.2015151111637.hdf
The file name begins with the Product Short Name (MOD09A1) followed by the Julian Date of Acquisition formatted as AYYYYDDD (A2002273), the Tile Identifier which is horizontal tile and vertical tile provided as hXXvYY (h29v03), the Version of the data collection (006), the Julian Date and Time of Production designated as YYYYDDDHHMMSS (2015151111637), and the Data Format (hdf).
Learn to interpret Moderate Resolution Imaging Spectroradiometer (MODIS) Surface Reflectance data quality via Quality Assurance bits, tools, and resources.
Leaf Area Index (LAI), Fraction Of Absorbed Photosynthetically Active Radiation (fapar), Vegetation Index, Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI), Reflectance
