MOD09A1 v061

MODIS/Terra Surface Reflectance 8-Day L3 Global 500 m SIN Grid

PI: Eric Vermote

Historic processing continues for MODIS V6.1 data products for years 2011 through 2018. It is the intent to complete processing of the archive by the end of the 2021 calendar year. The V6 land products will be available until the V6.1 processing is completed, upon which time the MODIS V6 products will be decommissioned.


The Moderate Resolution Imaging Spectroradiometer (MODIS) Terra MOD09A1 Version 6.1 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.

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Improvements/Changes from Previous Versions

  • The Version 6.1 Level-1B (L1B) products have been improved by undergoing various calibration changes that include: changes to the response-versus-scan angle (RVS) approach that affects reflectance bands for Aqua and Terra MODIS, corrections to adjust for the optical crosstalk in Terra MODIS infrared (IR) bands, and corrections to the Terra MODIS forward look-up table (LUT) update for the period 2012 - 2017.
  • A polarization correction has been applied to the L1B Reflective Solar Bands (RSB).

Product Maturity

Validation at stage 3 has been achieved for all MODIS Surface Reflectance products. Further details regarding MODIS land product validation for the MOD09 data products are available from the MODIS Land Team Validation site.

Collection and Granule


Characteristic Description
CollectionTerra MODIS
File Size59 MB
Temporal ResolutionMulti-Day
Temporal Extent2000-02-18 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
File FormatHDF
Geographic Dimensions1200 km x 1200 km


Characteristic Description
Number of Science Dataset (SDS) Layers13
Columns/Rows2400 x 2400
Pixel Size500 m


SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
sur_refl_b01 Surface Reflectance Band 1 (620-670 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b02 Surface Reflectance Band 2 (841-876 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b03 Surface Reflectance Band 3 (459-479 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b04 Surface Reflectance Band 4 (545-565 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b05 Surface Reflectance Band 5 (1230-1250 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b06 Surface Reflectance Band 6 (1628-1652 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b07 Surface Reflectance Band 7 (2105-2155 nm) N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_qc_500m Surface reflectance 500m band quality control flags Bit Field 32-bit unsigned integer 4294967295 N/A 0 to 4294966531 N/A
sur_refl_szen MODIS solar zenith angle Degree 16-bit signed integer 0 N/A 0 to 18000 0.01
sur_refl_vzen MODIS view zenith angle Degree 16-bit signed integer 0 N/A 0 to 18000 0.01
sur_refl_raz MODIS relative azimuth angle Degree 16-bit signed integer 0 N/A -18000 to 18000 0.01
sur_refl_state_500m Surface reflectance 500m state flags Bit Field 16-bit unsigned integer 65535 N/A 0 to 57343 N/A
sur_refl_day_of_year Day of the year for the pixel Julian day 16-bit unsigned integer 65535 N/A 1 to 366 N/A

Product Quality

The sur_refl_qc_500m and sur_refl_state_500m layers are 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 these layers.

The quality bit flags for sur_refl_qc_500m and the sur_refl_state_500m are given in the User Guide in Tables 10 and 13.

Known Issues

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

About the image

Terra MODIS surface reflectance band 1-4-3 data from the M0D09A1 product over the western United States, October 31 - November 7, 2020.

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User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data


DOI: 10.5067/MODIS/MOD09A1.061