Terra MODIS surface reflectance band 1-2-1 data from the MOD09Q1 product over the western United States, Nov ember 24 - December 1, 2020.View full-size image
The MOD09Q1 Version 6.1 product provides an estimate of the surface spectral reflectance of Terra 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.
|File Size||56 MB|
|Temporal Extent||2000-02-18 to Present|
|Geographic Dimensions||1200 km x 1200 km|
|Number of Science Dataset (SDS) Layers||4|
|Columns/Rows||4800 x 4800|
|Pixel Size||250 m|
|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|
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.
For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.