VJ109GA v002

VIIRS/JPSS1 Surface Reflectance Daily L2G Global 1 km and 500 m SIN Grid


PI: Eric Vermote, Belen Franch, Martin Claverie

Description

The Visible Infrared Imaging Radiometer Suite (VIIRS) daily surface reflectance (VJ109GA) Version 2 product provides an estimate of land surface reflectance from the NOAA-20 VIIRS sensor. Data are provided for three imagery bands (I1-I3) at nominal 500 meter resolution (~463 meter) and nine moderate resolution bands (M1-M5, M7, M8, M10, M11) at nominal 1 kilometer (~926 meter) resolution. The 500 meter and 1 kilometer datasets are derived through resampling the native 375 meter and 750 meter VIIRS resolutions, respectively, in the Level 2 input product. These bands are corrected for atmospheric conditions such as the effects of molecular gases, including ozone and water vapor, and for the effects of atmospheric aerosols.

The inputs to the surface reflectance algorithm are top-of-atmosphere reflectance for the VIIRS visible bands,the VIIRS cloud mask and aerosol product, aerosol optical thickness and atmospheric data obtained from the NOAA National Centers for Environmental Prediction (NCEP) reanalysis system. Along with the twelve reflectance bands are reflectance band quality, sensor azimuth angle, solar azimuth angle, sensor zenith angle, solar zenith angle, and observations layers. The reflectance layers from the VJ109GA data product are used as input data for many of the VIIRS land products.

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Characteristics

Improvements/Changes from Previous Versions

  • Improved calibration algorithm and coefficients for entire NOAA-20 mission.
  • Improved geolocation accuracy and applied updates to fix outliers around maneuver periods.
  • Corrected the aerosol quantity flag (low, average, high) mainly over brighter surfaces in the mid- to high-latitudes such as desert and tropical vegetation areas. This has an impact on the retrieval of other downstream data products such as VNP13 Vegetation Indices and VNP43 Bidirectional Reflectance Distribution Function (BRDF)/Albedo.
  • Improved cloud mask input product for corrections along coastlines and artifacts from use of coarse resolution climatology data.
  • Replaced the land/water mask input product with the eight-class land/water mask from the VNP03 geolocation product that better aligns with MODIS.
  • Added secondary day-night flag to improve retrieval of Climate Modeling Grid (CMG) values over daytime pixels.

More details can be found in this VIIRS Land V2 Changes document.

Product Maturity

Validation at stage 3 has been achieved for the VIIRS Land Surface Reflectance product suite. Visit VIIRS Land Product Quality Assessment Product Maturity for information on product maturity status.

Collection and Granule

Collection

Characteristic Description
CollectionNOAA-20 VIIRS
DOI10.5067/VIIRS/VJ109GA.002
File Size~105 MB
Temporal ResolutionDaily
Temporal Extent2018-01-01 to Present
Spatial ExtentGlobal
Coordinate SystemSinusoidal
DatumN/A
File FormatHDF-EOS5
Geographic Dimensions1200 km x 1200 km

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers30
Columns/Rows2400 (500 m) and 1200 (1000 m) x 2400 (500 m) and 1200 (1000 m)
Pixel Size1000 m and 500 m

Layers / Variables

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
SensorAzimuth_c Sensor Azimuth Angle Degree 16-bit signed integer -32768 N/A -18000 to 18000 0.01
SensorZenith_c Sensor Zenith Angle Degree 16-bit signed integer -32768 N/A 0 to 18000 0.01
SolarAzimuth_c Solar Azimuth Angle Degree 16-bit signed integer -32768 N/A -18000 to 18000 0.01
SolarZenith_c Solar Zenith Angle Degree 16-bit signed integer -32768 N/A 0 to 18000 0.01
SurfReflect_M1_c 1 km Surface Reflectance Band M1 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M2_c 1 km Surface Reflectance Band M2 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M3_c 1 km Surface Reflectance Band M3 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M4_c 1 km Surface Reflectance Band M4 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M5_c 1 km Surface Reflectance Band M5 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M7_c 1 km Surface Reflectance Band M7 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M8_c 1 km Surface Reflectance Band M8 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M10_c 1 km Surface Reflectance Band M10 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M11_c 1 km Surface Reflectance Band M11 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_I1_c 1 km Surface Reflectance Band I1 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_I2_c 1 km Surface Reflectance Band I2 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_I3_c 1 km Surface Reflectance Band I3 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_QF1_c Quality Flag 1 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
SurfReflect_QF2_c Quality Flag 2 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
SurfReflect_QF3_c Quality Flag 3 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
SurfReflect_QF4_c Quality Flag 4 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
SurfReflect_QF5_c Quality Flag 5 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
SurfReflect_QF6_c Quality Flag 6 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
SurfReflect_QF7_c Quality Flag 7 Bit Field 8-bit unsigned integer 255 N/A 0 to 254 N/A
land_water_mask_c Total Additional Observations 1km Bit Field 8-bit unsigned integer 255 N/A 0 to 7 N/A
nadd_obs_row_1km Observations coverage 1 km N/A 32-bit signed integer -1 N/A 0 to 2147483647 N/A
nadd_obs_row_500m Observation coverage 500 m N/A 32-bit signed integer -1 N/A 0 to 2147483647 N/A
orbit_pnt_c Orbit Pointer N/A 8-bit signed integer -1 N/A 0 to 15 N/A
iobs_res_c Observation number N/A 8-bit unsigned integer 255 N/A 0 to 254 N/A
obscov_1km_c Total Additional Observations 1km Percent 8-bit signed integer -1 N/A 0 to 100 .01
obscov_500m_c Total Additional Observations 500m Percent 8-bit signed integer -1 N/A 0 to 100 .01

Product Quality

The bit field mappings for Quality Flag (QF) layers 1 through 7 are provided in the User Guide under Section 3.3.

The Quality Control (QC) layer is 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.

Known Issues

For complete information about known issues please refer to the MODIS/VIIRS Land Quality Assessment website and in Section 4.0 of the User Guide.


About the image

The VJ109GA surface reflectance band M5-M4-M3 data over the Mojave Desert, United States on March 8, 2022.

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Documentation

User Guide

Algorithm Theoretical Basis Document (ATBD)

Using the Data

Access Data

Citation

DOI: 10.5067/VIIRS/VJ109GA.002