A global image of the VNP09CMG surface reflectance band M5-M4-M3 data from September 17, 2018.
View full-size imageThe Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance Climate Modeling Grid (VNP09CMG) Version 1 product provides an estimate of land surface reflectance from the NASA/NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) VIIRS sensor. Data are provided for three imagery bands (I1-I3) and nine moderate resolution bands (M1-M5, M7, M8, M10, M11) at 0.05 degree (~5,600 meter) resolution. The data are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols. This product uses a weighted average of the best quality observation and is formatted as a CMG for use in climate simulation models. This product includes the twelve reflectance bands, five moderate resolution brightness temperature bands (M12-M16) and information layers representing relative azimuth angle, sensor zenith angle, solar zenith angle, reflectance band quality, time of day, and number mapping.
Validation at stage 3 has been achieved for the VIIRS surface reflectance product suite. Visit VIIRS Land Product Quality Assessment Product Maturity for information on product maturity status.
| Characteristic | Description |
|---|---|
| Collection | Suomi NPP VIIRS |
| DOI | 10.5067/VIIRS/VNP09CMG.001 |
| File Size | ~850 MB |
| Temporal Resolution | Daily |
| Temporal Extent | 2012-01-19 to Present |
| Spatial Extent | Global |
| Coordinate System | Geographic Latitude and Longitude |
| Datum | N/A |
| File Format | HDF-EOS5 |
| Geographic Dimensions | Global |
| Characteristic | Description |
|---|---|
| Number of Science Dataset (SDS) Layers | 32 |
| Columns/Rows | 7200 x 3600 |
| Pixel Size | 5600 m |
| SDS Name | Description | Units | Data Type | Fill Value | No Data Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|---|
| SurfReflect_I1 | Surface Reflectance CMG Band I1 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_I2 | Surface Reflectance CMG Band I2 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_I3 | Surface Reflectance CMG Band I3 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M1_1 | Surface Reflectance CMG Band M1 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M2_1 | Surface Reflectance CMG Band M2 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M3_1 | Surface Reflectance CMG Band M3 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M4_1 | Surface Reflectance CMG Band M4 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M5_1 | Surface Reflectance CMG Band M5 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M7_1 | Surface Reflectance CMG Band M7 | N/A | 16-bit unsigned integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M8_1 | Surface Reflectance CMG Band M8 | N/A | 16-bit unsigned integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M10_1 | Surface Reflectance CMG Band M10 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_M11_1 | Surface Reflectance CMG Band M11 | N/A | 16-bit signed integer | -28672 | N/A | -100 to 16000 | 0.0001 |
| SurfReflect_QF_1 | Quality Flag 1 | Bit Field | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| SurfReflect_QF_2 | Quality Flag 2 | Bit Field | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| SurfReflect_QF_3 | Quality Flag 3 | Bit Field | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| SurfReflect_QF_4 | Quality Flag 4 | Bit Field | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| SurfReflect_QF_5 | Quality Flag 5 | Bit Field | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| SurfReflect_QF_6 | Quality Flag 6 | Bit Field | 8-bit unsigned integer | 255 | N/A | 0 to 254 | N/A |
| BrightTemp_M12 | Brightness Temperature CMG Band M12 | Kelvin | 16-bit unsigned integer | 0 | N/A | 1 to 40000 | 0.01 |
| BrightTemp_M13 | Brightness Temperature CMG Band M13 | Kelvin | 16-bit unsigned integer | 0 | N/A | 1 to 40000 | 0.01 |
| BrightTemp_M14 | Brightness Temperature CMG Band M14 | Kelvin | 16-bit unsigned integer | 0 | N/A | 1 to 40000 | 0.01 |
| BrightTemp_M15 | Brightness Temperature CMG Band M15 | Kelvin | 16-bit unsigned integer | 0 | N/A | 1 to 40000 | 0.01 |
| BrightTemp_M16 | Brightness Temperature CMG Band M16 | Kelvin | 16-bit unsigned integer | 0 | N/A | 1 to 40000 | 0.01 |
| Granule_Time | Granule Time | Hours | 16-bit signed integer | 0 | N/A | 1 to 2355 | 1 |
| Number_Mapping_1 | Number Mapping 1 Adjacent cloud/snow | N/A | 32-bit unsigned integer | 0 | N/A | 1 to 2097151 | N/A |
| Number_Mapping_2 | Number Mapping 2 cloud/cloud shadow | N/A | 32-bit unsigned integer | 0 | N/A | 1 to 2097151 | N/A |
| n_375m_pixels_averaged | Number 375 m pixels averaged | N/A | 16-bit unsigned integer | 0 | N/A | 1 to 800 | N/A |
| n_750m_pixels_averaged | Number 750 m pixels averaged | N/A | 16-bit unsigned integer | 0 | N/A | 1 to 200 | N/A |
| State_QA | CMG State Quality Assurance (QA) flags | Bit Field | 16-bit signed integer | 0 | N/A | 1 to 65535 | N/A |
| RelativeAzimuth | Relative azimuth angle | Degree | 16-bit signed integer | 0 | N/A | 1 to 18000 | 0.01 |
| SensorZenith | Sensor zenith angle | Degree | 16-bit signed integer | 0 | N/A | 1 to 18000 | 0.01 |
| SolarZenith | Solar zenith angle | Degree | 16-bit signed integer | 0 | N/A | 1 to 18000 | 0.01 |
The bit field mappings for quality flag (QF) layers 1 through 6 and number mapping are provided in Section 3.3 and 3.4 Tables 20 through 22 of the User Guide.
The quality flag (QF) 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 quality layer.
Quality assurance information should be considered when determining the usability of data for a particular science application. The ArcGIS MODIS-VIIRS Python Toolbox contains tools capable of decoding quality data layers while producing thematic quality raster files for each quality attribute.
For complete information about product quality, refer to the VIIRS Land Product Quality Assessment web site.
The VIIRS Land Surface Reflectance product (VNP09) may incorrectly flag retrievals as ‘High Aerosol’ over brighter surfaces and at higher view angles. This will impact the downstream VIIRS BRDF/Albedo (VNP43) and Vegetation Index (VNP13) data products which use the aerosol quantity flag to screen out high aerosol values.
Corrections will be implemented in Collection 2 reprocessing in 2022.
For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website and in Section 4.0 “Caveats and Known Problems” of the User Guide.