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 VNP43C4 Climate Modeling Grid (CMG) Nadir BRDF-Adjusted Reflectance (NBAR) Product is computed at a 0.05 degree spatial resolution for each of the VIIRS spectral M bands (M1–M5, M7–M8 and M10–M11) and the Day Night Band (DNB) at the local solar noon zenith angle of the day of interest. The data are provided in global files in a geographic (lat/long) projection. Since the view angle effects have been removed from the directional reflectances, the result is a stable and consistent reflectance product. These NBAR values are calculated from the BRDF model parameters from VNP43C1. Note that along coastlines, this means that the 30arcsecond pixels that lie over shallow water will be averaged into the 0.05 degree CMG pixel. In addition to the spectral and broadband albedo quantities themselves, the VNP43C4 CMG NBAR Product also provides mandatory quality information. The quality and inversion status of the majority of the underlying 30arcsecond pixels is provided as well as the percentage of the underlying pixels that were present or were snow covered. Therefore, quality should be considered with caution when using this product for quantitative results.