VJ109H1 v002

VIIRS/JPSS1 Surface Reflectance 8-Day L3 Global 500 m SIN Grid


PI: Eric Vermote, Belen Franch, Martin Claverie

Description

The 8-day Visible Infrared Imaging Radiometer Suite (VIIRS) Surface Reflectance (VJ109H1) Version 2 composite product provides an estimate of land surface reflectance from the NOAA-20 VIIRS sensor for three imagery bands (I1, I2, I3) at nominal 500 meter resolution (~463 meter). The 500 meter dataset is derived through resampling the native 375 meter VIIRS resolution in the L2 input product. 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. Each pixel represents the best possible Level 2G observation during an 8-day period, which is selected on the basis of high observation coverage, low sensor angle, the absence of clouds or cloud shadow, and aerosol loading. This product includes three reflectance bands, a state quality assurance (QA) layer, and a reflectance band quality layer.

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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/VJ109H1.002
File Size~26 MB
Temporal ResolutionMulti-Day
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) Layers5
Columns/Rows2400 x 2400
Pixel Size500 m

Layers / Variables

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
SurfReflect_I1 500 m Surface Reflectance Band I1 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_I2 500 m Surface Reflectance Band I2 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_I3 500 m Surface Reflectance Band I3 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_State_500m Surface Reflectance State Quality Assurance (QA) Bit Field 16-bit unsigned integer 65535 N/A 0 to 13311 N/A
SurfReflect_QC_500m Surface Reflectance Band Quality Control (QC) Bit Field 16-bit unsigned integer 65535 N/A 0 to 32767 N/A

Product Quality

The bit field mappings for QC and State QA layers are provided in Section 3.3 Tables 17 and 19 of the User Guide.

The Quality Control (QC) and State QA 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.

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 VJ109H1 surface reflectance band I3-I2-I1 data over the Mojave Desert, United States, September 6 to September 13, 2018.

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Documentation

User Guide

Algorithm Theoretical Basis Document (ATBD)

Using the Data

Access Data

Citation

DOI: 10.5067/VIIRS/VJ109H1.002