VNP43C1 v001

VIIRS/NPP BRDF/Albedo Model Parameters Daily L3 Global 0.05 Deg CMG


PI: Crystal Schaaf

Description

The Suomi National Polar-Orbiting Partnership (S-NPP) NASA Visible Infrared Imaging Radiometer Suite (VIIRS) Bidirectional Reflectance Distribution Function (BRDF) and Albedo Model Parameters Daily Global 0.05 Degree Climate Modeling Grid (CMG) Version 1 product (VNP43C1) is derived from the 30 arc second CMG VNP43D Version 1 product suite. VNP43C1 is generated daily from all available high-quality reflectance data over a 16-day moving window emphasizing the ninth day of the retrieval period, which is reflected in the Julian date in the filename. VNP43C1 supplies the weighting parameters associated with the RossThick/Li-Sparse-Reciprocal BRDF model that best describes the anisotropy of each pixel, which is used to produce the VNP43C3 Albedo and VNP43C4 Nadir BRDF-Adjusted Reflectance (NBAR) products. The highest quality full inversion values are used for the temporal fitting effort and supplemented with lower quality pixels, spatial fitting, and spatial smoothing as needed. The status of each pixel can be found in the ancillary layers. Users are encouraged to assess the quality information before using the BRDF/Albedo data. This 0.05 degree (5,600 meters at the equator) CMG product covers the entire globe for use in climate simulation models.

The VNP43C1 product includes 39 layers containing the three parameters (fiso, fvol, and fgeo) for the VIIRS Day/Night band (DNB), moderate resolution bands M1 through M5, M7, M8, M10, and M11, as well as the shortwave band, visible band, and near-infrared (NIR) broadbands. Along with the parameter data for the 13 bands are five ancillary layers for uncertainty, quality, local solar noon, percent finer resolution inputs, and snow cover. A low-resolution browse is also provided showing BRDF/Albedo parameters for bands M5, M4, and M3 as a red, green, blue (RGB) image in JPEG format.

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Characteristics

Product Maturity

Validation at stage 1 has been achieved for the VIIRS BRDF/Albedo product suite. Visit the VIIRS Land Product Quality Assessment website for additional information on validation and product maturity status.

Collection and Granule

Collection

Characteristic Description
CollectionS-NPP VIIRS
DOI10.5067/VIIRS/VNP43C1.001
File Size~244 MB
Temporal ResolutionDaily
Temporal Extent2012-01-19 to Present
Spatial ExtentGlobal
Coordinate SystemGeographic Latitude and Longitude
DatumN/A
File FormatHDF-EOS5
Geographic DimensionsGlobal

Granule

Characteristic Description
Number of Science Dataset (SDS) Layers44
Columns/Rows7200 x 3600
Pixel Size5600 m

Layers

SDS Name Description Units Data Type Fill Value No Data Value Valid Range Scale Factor
BRDF_Albedo_Parameter1_DNB BRDF Albedo isotropic weight for Day/Night band (0.7 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M1 BRDF Albedo isotropic weight for band M1 (0.412 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M10 BRDF Albedo isotropic weight for band M10 (1.61 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M11 BRDF Albedo isotropic weight for band M11 (2.25 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M2 BRDF Albedo isotropic weight for band M2 (0.445 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M3 BRDF Albedo isotropic weight for band M3 (0.488 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M4 BRDF Albedo isotropic weight for band M4 (0.555 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M5 BRDF Albedo isotropic weight for band M5 (0.672 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M7 BRDF Albedo isotropic weight for band M7 (0.865 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_M8 BRDF Albedo isotropic weight for band M8 (1.240 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_nir BRDF Albedo isotropic weight for NIR broadband (0.865 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_shortwave BRDF Albedo isotropic weight for shortwave broadband (1.61 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter1_vis BRDF Albedo isotropic weight for vis broadband (0.64 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_DNB BRDF Albedo volumetric weight for Day/Night band (0.7 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M1 BRDF Albedo volumetric weight for band M1 (0.412 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M10 BRDF Albedo volumetric weight for band M10 (1.61 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M11 BRDF Albedo volumetric weight for band M11 (2.25 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M2 BRDF Albedo volumetric weight for band M2 (0.445 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M3 BRDF Albedo volumetric weight for band M3 (0.488 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M4 BRDF Albedo volumetric weight for band M4 (0.555 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M5 BRDF Albedo volumetric weight for band M5 (0.672 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M7 BRDF Albedo volumetric weight for band M7 (0.865 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_M8 BRDF Albedo volumetric weight for band M8 (1.240 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_nir BRDF Albedo volumetric weight for NIR broadband (0.865 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_shortwave BRDF Albedo volumetric weight for shortwave broadband (1.61 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter2_vis BRDF Albedo volumetric weight for vis broadband (0.64 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_DNB BRDF Albedo geometric weight for Day/Night band (0.7 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M1 BRDF Albedo geometric weight for band M1 (0.412 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M10 BRDF Albedo geometric weight for band M10 (1.61 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M11 BRDF Albedo geometric weight for band M11 (2.25 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M2 BRDF Albedo geometric weight for band M2 (0.445 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M3 BRDF Albedo geometric weight for band M3 (0.488 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M4 BRDF Albedo geometric weight for band M4 (0.555 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M5 BRDF Albedo geometric weight for band M5 (0.672 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M7 BRDF Albedo geometric weight for band M7 (0.865 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_M8 BRDF Albedo geometric weight for band M8 (1.240 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_nir BRDF Albedo geometric weight for NIR broadband (0.865 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_shortwave BRDF Albedo geometric weight for shortwave broadband (1.61 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Parameter3_vis BRDF Albedo geometric weight for vis broadband (0.64 μm) N/A 16-bit signed integer 32767 N/A 0 to 32766 0.001
BRDF_Albedo_Uncertainty BRDF inversion information N/A 16-bit unsigned integer 32767 N/A 0 to 32766 0.001
BRDF_Quality BRDF and albedo quality information N/A 8-bit unsigned integer 255 N/A 0 to 5 N/A
Local_Solar_Noon Local solar noon zenith angle Degree 8-bit unsigned integer 255 N/A 0 to 90 N/A
Percent_Inputs Percent finer resolution data which contributed to the CMG Percent 8-bit unsigned integer 255 N/A 0 to 100 N/A
Percent_Snow Percent of underlying data flagged as snow Percent 8-bit unsigned integer 255 N/A 0 to 100 N/A

Quality bit index

Value Description
0 Best quality, 100% with full inversions
1 Good quality, 75% or more with best full inversions and 90% or more with full inversions
2 Relative good quality, 75% or more with full inversions
3 Mixed, 75% or less full inversions and 25% or less fill values
4 All magnitude inversions or 50% or less fill values
5 50% or more fill values
255 Fill value

Product Quality

The quality and inversion status of the majority of the underlying 30 arc second pixels is provided as well as the percentage of the underlying pixels that were present or were snow covered. Therefore, quality should be considered when using this product for quantitative results. Product accuracy/uncertainty information can be found in section 4 of the Algorithm Theoretical Basis Document (ATBD).

Known Issues

The VIIRS Land Surface Reflectance product (VNP09) flags a larger number of retrievals as ‘High Aerosol’ in the quality layer as compared to the MODIS reflectance product. The inaccurately flagged high aerosol quality flags cause the BRDF retrieval algorithm to incorrectly reject the observations and switch from full inversion (high quality retrieval) to magnitude inversion (low quality retrieval) in the mid to high latitude, arid lands, and tropical vegetative regions.

Documentation

Using the Data

Tools

Citation

DOI: 10.5067/VIIRS/VNP43C1.001

About the Image

VIIRS BRDF Albedo RGB model parameters data from the VNP43C1 global product on January 1, 2017.

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