Description
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.
Known Issues
- For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website.
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).
Version Description
Product Summary
Citation
Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.
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File Naming Convention
The file name begins with the Product Short Name (MOD09A1) followed by the Julian Date of Acquisition formatted as AYYYYDDD (A2025209), the Tile Identifier which is horizontal tile and vertical tile provided as hXXvYY (h28v12), the Version of the data collection (061), the Julian Date and Time of Production designated as YYYYDDDHHMMSS (2025218035852), and the Data Format (hdf).
Documents
USER'S GUIDE
ALGORITHM THEORETICAL BASIS DOCUMENT (ATBD)
PRODUCT QUALITY ASSESSMENT
SCIENCE DATA PRODUCT VALIDATION
Publications Citing This Dataset
Variables
Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.
The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.
| Name Sort descending | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|
| sur_refl_b01 | Surface Reflectance Band 1 (620-670 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_b02 | Surface Reflectance Band 2 (841-876 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_b03 | Surface Reflectance Band 3 (459-479 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_b04 | Surface Reflectance Band 4 (545-565 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_b05 | Surface Reflectance Band 5 (1230-1250 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_b06 | Surface Reflectance Band 6 (1628-1652 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_b07 | Surface Reflectance Band 7 (2105-2155 nm) | N/A | int16 | -28672 | -28672 to 16000 | 0.0001 |
| sur_refl_day_of_year | Day of the year for the pixel | Julian day | uint16 | 65535 | 65535 to 366 | N/A |
| sur_refl_qc_500m | Surface reflectance 500m band quality control flags | Bit Field | uint32 | 4294967295 | 4294967295 to 4294966531 | N/A |
| sur_refl_raz | MODIS relative azimuth angle | Degree | int16 | 0 | 0 to 18000 | 0.01 |
| sur_refl_state_500m | Surface reflectance 500m state flags | Bit Field | uint16 | 65535 | 65535 to 57343 | N/A |
| sur_refl_szen | MODIS solar zenith angle | Degree | int16 | 0 | 0 to 18000 | 0.01 |
| sur_refl_vzen | MODIS view zenith angle | Degree | int16 | 0 | 0 to 18000 | 0.01 |