VJ109A1 v002

VIIRS/JPSS1 Surface Reflectance 8-Day L3 Global 1 km SIN Grid


PI: Eric Vermote, Belen Franch, Martin Claverie

Description

The 8-day Visible Infrared Imaging Radiometer Suite (VIIRS) surface reflectance (VJ109A1) Version 2 composite product provides an estimate of land surface reflectance from the NOAA-20 VIIRS sensor for nine moderate resolution bands (M1 - M5, M7, M8, M10, M11) at nominal 1 kilometer resolution (~926 meter). The 1 kiliometer dataset is derived through resampling the native 750 meter VIIRS resolution in the Level 2 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 that is selected on the basis of high observation coverage, low sensor angle, the absence of clouds or cloud shadow, and aerosol loading. Included in the product along with the nine reflectance bands are day of year, reflectance band quality, control, reflectance state quality assurance, relative azimuth angle, sensor zenith angle, and solar zenith angle layers.

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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/VJ109A1.002
File Size~24 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) Layers15
Columns/Rows1200 x 1200
Pixel Size1000 m

Layers / Variables

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
RelativeAzimuth Relative Azimuth Angle Degree 16-bit signed integer -18001 N/A -18000 to 18000 0.01
SolarZenith Solar Zenith Angle Degree 16-bit signed integer 0 N/A 1 to 18000 0.01
SensorZenith SensorZenith Angle Degree 16-bit signed integer 0 N/A 1 to 18000 0.01
SurfReflect_Day_Of_Year Day of Year Julian day 16-bit unsigned integer 65535 N/A 1 to 366 N/A
SurfReflect_M1 1 km Surface Reflectance Band M1 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M2 1 km Surface Reflectance Band M2 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M3 1 km Surface Reflectance Band M3 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M4 1 km Surface Reflectance Band M4 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M5 1 km Surface Reflectance Band M5 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M7 1 km Surface Reflectance Band M7 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M8 1 km Surface Reflectance Band M8 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M10 1 km Surface Reflectance Band M10 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_M11 1 km Surface Reflectance Band M11 N/A 16-bit signed integer -28672 N/A -100 to 16000 0.0001
SurfReflect_State Surface Reflectance State Quality Assurance (QA) Bit Field 16-bit unsigned integer 65535 N/A 0 to 13311 N/A
SurfReflect_QC Surface Reflectance Band Quality Control (QC) Bit Field 32-bit unsigned integer 4294967295 N/A 0 to 4294967294 N/A

Product Quality

The bit field mappings for QC and State QA layers are provided under Section 3.3 Tables 18 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 VJ109A1 surface reflectance band M5-M4-M3 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/VJ109A1.002