MYD09Q1 v061

MODIS/Aqua Surface Reflectance 8-Day L3 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.

Description

The MYD09Q1 Version 6.1 product provides an estimate of the surface spectral reflectance of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Bands 1 and 2, corrected for atmospheric conditions such as gasses, aerosols, and Rayleigh scattering. Provided along with the 250 meter (m) surface reflectance bands are two quality layers. 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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Characteristics

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

Collection

Characteristic Description
CollectionAqua MODIS
DOI10.5067/MODIS/MYD09Q1.061
File Size56 MB
Temporal ResolutionMulti-Day
Temporal Extent2002-07-04 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
DatumN/A
File FormatHDF
Geographic Dimensions1200 km x 1200 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers4
Columns/Rows4800 x 4800
Pixel Size250 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
sur_refl_b01 Surface Reflectance Band 1 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_b02 Surface Reflectance Band 2 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
sur_refl_state_250m Surface Reflectance 250m State flags Bit Field 16-bit unsigned integer 65535 N/A 0 to 57343 N/A
sur_refl_qc_250m Surface Reflectance 250m Band Quality Control flags Bit Field 16-bit unsigned integer 65535 N/A 0 to 32767 N/A

Product Quality

The sur_refl_state_250m and sur_refl_qc_250m 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 the QC layers.

The QA bit flags for the sur_refl_state_250m and sur_refl_qc_250m layers are provided in the User Guide in Tables 13 and 9 respectively.

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 1-2-1 data from the MYD09Q1 product over the western United States, November 25 - December 1, 2020.

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Documentation

User Guide
Algorithm Theoretical Basis Document (ATBD)
File Specification

Using the Data

Access Data

Citation

DOI: 10.5067/MODIS/MYD09Q1.061