MYD09Q1 v006

MODIS/Aqua Surface Reflectance 8-Day L3 Global 250 m SIN Grid


PI: Eric Vermote

Description

The MYD09Q1 Version 6 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.

Characteristics

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 Maturity

Validation at stage 3 has been achieved for all MODIS surface reflectance products. Further details regarding MODIS land product validation for the MYD09Q1 data product is available from the MODIS land team validation site.

Collection and Granule

Collection

Characteristic Description
CollectionAqua MODIS
DOI10.5067/MODIS/MYD09Q1.006
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.

In addition to data access and transformation processes, AppEEARS also has the capability to unpack and interpret the quality 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 the MYD09Q1 known issues please refer to the MODIS Land Quality Assessment website.

Documentation

Using the Data

E-Learning

Getting Started with MODIS V6 Surface Reflectance Data Part 3: Interpreting Quality Information

Data In Action

Highlights from the Literature: April to June 2016

The NASA DEVELOP National Program Spring/Summer 2014

Tools

Citation

DOI: 10.5067/MODIS/MYD09Q1.006

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