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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.
  • For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.

Improvements/Changes from Previous Versions

  • Improvements to the aerosol retrieval and correction algorithm along with new aerosol retrieval look-up tables.
  • 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.
  • Processes ocean bands to create a new Surface Reflectance Ocean product and provides Quality Assurance (QA) datasets for these bands.
  • Improved discrimination of salt pans from cloud and snow, along with the inclusion of a salt pan flag in the QA band.

Product Summary

Platforms
Terra
Instruments
MODIS
Spatial Extent
N: 90 S: -90 E: 180 W: -180
Spatial Resolution
500 Meters x 500 Meters
Geographic Region
GLOBAL
Coordinate System
CARTESIAN
Granule Spatial Representation
GEODETIC
Temporal Extent
2000-02-24 to 2023-02-17
Temporal Resolution
8 Day
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC)
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)
Concept ID
c2763297170-lpcloud
Data State
DEPRECATED
Processing Level
3
Published
Updated

Citation

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.

Copy Citation

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: 2025-06-22

Data Center Citation

Eric Vermote. 2015. MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V006. Sioux Falls, South Dakota, USA: NASA Land Processes Distributed Active Archive Center. https://doi.org/10.5067/MODIS/MOD09A1.006.

Documents

ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD) The ATBD provides physical theory and mathematical procedures for the calculations used to produce the data products.
GENERAL DOCUMENTATION The File Specification provides a description of the product file including Scientific Data Sets and their attributes.
PRODUCT QUALITY ASSESSMENT The LDOPE Land Product Quality Assessment website provides known issues, maneuvers, and product quality of the land products.
USER'S GUIDE The technical information in the User's Guide enables users to interpret and use the data products.

Learning Resources

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