UMass Boston

VIIRS User Guide Collection 1

This Guide is a living document that describes the VIIRS BRDF and Albedo Products. The purpose of the document is to give the potential user an understanding of the VNP43 products and the current state of the data in those products.

Note: Users are urged to use the band specific quality flags to isolate the highest quality full inversion results for their own science applications. 

The VNP43IA4 and VNP43MA4 Nadir BRDF-Adjusted Reflectance (NBAR) Products are computed for each of the VIIRS spectral bands at the local solar noon of the day of interest.VNP43IA4 provides information at the three VIIRS Imagery bands (I1, I2, and I3) at 500m scale, and VNP43MA4 provides information at the nine Moderate bands (M1- M5, M7-M8, M10-M11). The view angle effects will have been removed from the directional reflectances, resulting in a more stable and consistent product. These products are primarily used for land cover and phenology monitoring.

Science Data Sets

The NBAR product includes two Science Data Sets (SDS) for each pixel in the tile. These SDSs are Nadir_Reflectance (computed for spectral bands at the local solar noon zenith angle of the day of interest) and BRDF_Albedo_Band_Mandatory_Quality SDS (containing 1 byte of quality flags).

Note that the Collection 1 VIIRS VNP43 products are retrieved daily and represent the best BRDF possible based on 16 days’ worth of inputs with the day of interest (the center date of the 16 day retrieval period) emphasized.

File Specifications

The File Specifications for VNP43IA3 and VNP43MA3 are at https://ladsweb.modaps.eosdis.nasa.gov/filespec/VIIRS/collection1

Local Attributes

In addition to the actual SDS data values produced at each pixel in a tile, each SDS can be  associated with a number of standard Local Attributes that apply to the data.