MYD09GQ v061

MODIS/Aqua Surface Reflectance Daily L2G Global 250 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 MYD09GQ Version 6.1 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) 250 meter (m) bands 1 and 2, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Along with the 250 m bands are the Quality Assurance (QA) layer and five observation layers. This product is intended to be used in conjunction with the quality and viewing geometry information of the 500 m product (MYD09GA).

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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 the MODIS Surface Reflectance products. Further details regarding MODIS land product validation for the MYD09 data product is available from the MODIS Land Team Validation site.

Collection and Granule


Characteristic Description
CollectionAqua MODIS
File Size84 MB
Temporal ResolutionDaily
Temporal Extent2002-07-04 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
File FormatHDF
Geographic Dimensions1200 km x 1200 km


Characteristic Description
Number of Science Dataset (SDS) Layers8
Columns/Rows4800 x 4800
Pixel Size250 m


SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
num_observations Number of observations per 250m pixel N/A 8-bit signed integer -1 N/A 0 to 127 N/A
sur_refl_b01_1 Surface Reflectance Band 1 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b02_1 Surface Reflectance Band 2 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
QC_250m_1 Surface Reflectance 250m Quality Assurance Bit Field 16-bit unsigned integer 2995 N/A 0 to 4096 N/A
obscov_1 Observation coverage Percent 8-bit signed integer -1 N/A 0 to 100 0.01
iobs_res_1 Observation number N/A 8-bit unsigned integer 255 N/A 0 to 254 N/A
orbit_pnt_1 Orbit pointer N/A 8-bit signed integer -1 N/A 0 to 15 N/A
granule_pnt _1 Granule pointer N/A 8-bit unsigned integer 255 N/A 0 to 254 N/A

The Number of Science Dataset Layers is a minimum of 8. If the "L2G Storage Format" metadata value is "full" additional data layers are present with the suffix _f. If the "L2GStorageFormat" metadata value is "compact" additional data layers are present with the suffix _c.

Product Quality

The QC_250m_1 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.

The QA bit flags for the QC_250m_1 layer is provided in Table 8 of the User Guide.

Known Issues

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

About the image

Aqua MODIS surface reflectance band 1-1-2 data from the MYD09GQ product over the western United States, Dececmber 4, 2020.

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User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data


DOI: 10.5067/MODIS/MYD09GQ.061