This document describes the Suomi National Polar-orbiting Partnership Visible Infrared Imaging Radiometer Suite (S-NPP/VIIRS) active fire detection products based on that instrument’s 375 m (I-bands) and 750 m (M-bands) nominal resolution Collection 1 (C1) reprocessed data from the NASA Land Science Investigator Processing System (SIPS). The VIIRS instrument was first launched on 28 October 2011, and is to be superseded by other similar instruments on board the Joint Polar Satellite System (JPSS) to enter operations in 2017. The first active fires detected with the VIIRS sensor occurred on 19 January 2012, when the instrument was fully commissioned.

The NASA Land-SIPS VIIRS 750 m active fire product (hereafter referred to as VNP14) evolved from the baseline algorithm implementation designed to provide continuity to the 1-km Earth Observing System Moderate Resolution Imaging Spectroradiometer (EOS/MODIS) active fire data record [Csiszar et al., 2014]. The original version of the VIIRS 750 m active fire product was based on the MODIS Fire and Thermal Anomalies (MOD14/MYD14) Collection 4 algorithm [Giglio et al., 2003], although lacking some key output science data sets found in the MODIS product such as the 2D image classification product (fire mask), and sub-pixel fire radiative power retrievals (FRP)[Csiszar et al., 2014]. That product was later replaced with the latest version (Collection 6) of the MODIS active fire algorithm equivalent [Giglio et al., 2016], incorporating all the missing output science data layers. NASA’s Land-SIPS adopted the “VNP14” nomenclature for that version of the product. The NASA Land-SIPS VIIRS 375 m active fire product (hereafter referred to as VNP14IMG) was proposed during the early post-launch period following the successful application of the 375 m data for active fire detection. This new application constituted a repurposing of the VIIRS 375 m (I) channels, as none of these channels were originally designed for active fire detection. Most importantly, abnormal radiometric conditions involving different pixel saturation scenarios are frequently observed in the primary mid-infrared (I4) channel, thereby requiring special handling of the data. Building on the MOD14/MYD14 algorithm, several modifications were implemented to accommodate the unique characteristics associated with the VIIRS 375 m data [Schroeder et al., 2014]. As a new application, the VNP14IMG data set is deemed experimental–the product’s status is expected to change in the near future as provisions are added to the VIIRS program. Due to its higher spatial resolution, the VNP14IMG active fire product provides greater response over fires of relatively small areas, as well as improved mapping of large fire perimeters. In comparison, the VNP14 fire data set provides rather similar performance relative to the MYD14 1-km product. Consequently, users should be aware of those differences and select the data set that is most appropriate for their own applications.