S-NPP Product Descriptions: VNP43MA4N

Last update: November 20, 2023

Data Set Short Name:
VNP43MA4N

Data Set Long Name:
VIIRS/NPP Nadir BRDF-Adjusted Reflectance Daily L3 Global 1 km SIN Grid NRT

Platform:
Suomi National Polar-orbiting Partnership (S-NPP)

Instrument:
Visible Infrared Imaging Radiometer Suite (VIIRS)

Product Description:
The Near Real Time (NRT) Suomi National Polar-Orbiting Partnership (S-NPP) NASA Visible Infrared Imaging Radiometer Suite (VIIRS) Nadir Bidirectional Reflectance Distribution Function (BRDF) Adjusted Reflectance (NBAR), (VNP43MA4N) product provides NBAR estimates at 1 kilometer (km) resolution. The VNP43MA4N product is produced daily using 16-day VIIRS data (i.e., the current day and the previous 15 days). The view angle effects are removed from the directional reflectances resulting in a stable and consistent NBAR product. The VNP43 data products are designed to promote the continuity of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF/Albedo data product suite.

The VNP43 algorithm uses the RossThick/Li-Sparse-Reciprocal (RTLSR) semi-empirical kernel-driven BRDF model, with the three kernel weights from VNP43MA1N to reconstruct surface anisotropic effects, correcting the directional reflectance to a common view geometry (VNP43MA4N), while also computing integrated black-sky albedo (BSA) at local solar noon and white-sky albedo (WSA) (VNP43MA3N). Researchers can use the BRDF model parameters with a simple polynomial, to obtain black-sky albedo at any solar illumination angle. Likewise, both the BSA and WSA Science Dataset (SDS) layers can be used with a simple polynomial, to manually estimate instantaneous actual albedo (blue-sky albedo). Additional details regarding the methodology are available in the Algorithm Theoretical Basis Document (ATBD).

The VNP43MA4N data product provides a total of 18 SDS layers for BRDF/Albedo mandatory quality and nadir reflectance for VIIRS nine moderate bands M1-M5, M7-M8, and M10-M11.

file_naming_convention = "VNP43MA4N.AYYYYDDD.hXXvYY.CCC.YYYYDDDHHMMSS.h5

• AYYYYDDD = Acquisition Year and Day of Year
• HHMM = Hour and minute of acquisition
• hXXvYY = Sinusoidal Tile Identifier (horizontalXXverticalYY)
• CCC = Collection Version number
• YYYYDDDHHMMSS = Julian Date and time of Production in Year, Day of Year, hour, minute, and seconds
• h5 = HDF-EOS (version 5) file format

Production Frequency:
~460 file per day

Spatial Coverage:
Global

Spatial Resolution:
1 km

File Size (MB):
~100

Citation:

Dataset Originator/Creator:
NASA Suomi-NPP Land Science Team/Land, Atmosphere Near real-time Capability for EOS (LANCE)Moderate Resolution Imaging Spectroradiometer (MODIS)

Data Authors:
Dr. Crystal B. Schaaf

Dataset DOI:
http://dx.doi.org/10.5067/VIIRS/VNP43MA4N.002