VNP46A2 - VIIRS/NPP Gap-Filled Lunar BRDF-Adjusted Nighttime Lights Daily L3 Global 500m Linear Lat Lon Grid

The Suomi National Polar-orbiting Partnership (SNPP) Visible Infrared Imaging Radiometer Suite (VIIRS) supports a Day-Night Band (DNB) sensor that provides global daily measurements of nocturnal visible and near-infrared (NIR) light that are suitable for Earth system science and applications. The VIIRS DNB's ultra-sensitivity in lowlight conditions enable us to generate a new set of science-quality nighttime products that manifest substantial improvements in sensor resolution and calibration when compared to the previous era of Defense Meteorological Satellite Program/Operational Linescan System's (DMSP/OLS) nighttime lights image products. Such improvements allow the VIIRS DNB products to better monitor both the magnitude and signature of nighttime phenomena, and anthropogenic sources of light emissions.

VNP46A2 is the short-name for the daily moonlight- and atmosphere-corrected Nighttime Lights (NTL) product called VIIRS/NPP Gap-Filled Lunar BRDF-Adjusted Nighttime Lights Daily L3 Global 500m Linear Lat Lon Grid. This product contains seven Science Data Sets (SDS) that include the following:

1. DNB BRDF-Corrected NTL
2. Gap-Filled DNB BRDF-Corrected NTL
3. DNB Lunar Irradiance
4. Latest High-Quality Retrieval
5. Mandatory Quality Flag
6. Cloud Mask Quality Flag
7. Snow Flag

VNP46A2 products are provided in standard Hierarchical Data Format-Earth Observing System (HDF-EOS5) format. The VNP46A2 product has been validated through various field campaigns of opportunity supported under the Group on Earth Observations (GEO) Human Planet Initiative's Nighttime Product Validation (NPV) task. Additionally, the VNP46 product suite comes with ancillary and quality assessment layers indicating sources of error from the calibration, cloud mask, snow flag, and lunar irradiance, etc. We remind our end-users that Collection 1 is considered Beta version due to ongoing issues with the heritage nighttime cloud mask, snow flag and aerosol layers. Users should also be aware of the angular anisotropic characteristic of nighttime lights for quantitative analysis. This SNPP VIIRS collection-1 product record, identified by its version-ID 001 in its file name, starts from January 19, 2012.

Processing Chain Provenance
This section instructs users regarding where to find the source locations for three provenance-specific information artifacts in the global metadata attributes.

Processing steps used to generate the SNPP VIIRS VNP46 product: The data product inputs, the algorithm processing flow, and all other pertinent details that help create the VIIRS Nighttime Lights products are described in the following two sources:

1. The Black Marble User Guide (Version 1.2, September 2022)
2. The Black Marble Algorithm Theoretical Basis Document (Version 1.1, July 2020)

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The data producer's name and email: This information does not currently exist in the global metadata attributes, and is slated for addition in the next reprocessing cycle.

The production software (PGE) version used: The processing software used to generate the product is called a Product Generation Executable or PGE, and is identified via the following two pieces of information in the global metadata attributes:

1. PGE_Name, which is an alphanumeric value, e.g., “PGE554”
2. PGE Version, which is a numeric value, e.g., “1.0.10”

The PGE name and its version help associate the exact production software that was used to generate any specific version of the data product.