The NOAA Operational VIIRS Active Fire Product: Recent Updates and Long-term Plans

The current NOAA operational VIIRS 375m “I-band” active fire product is based on the legacy algorithm which performs fire detection using a set of thresholding and contextual tests, and calculates top-of-atmosphere fire radiative power (FRP) from 4 micron M13 “fire band” measurements partitioned over the I-band detections within the 750m M-band footprint. In 2023 the code base to execute this algorithm transitioned to the new Enterprise Fire product, which also includes some changes in product content to make the core output information uniform across products from multiple sensors. The NOAA-21 VIIRS I-band active fire product achieved provisional maturity in June 2023, and produced FRP retrievals as expected after the adjustment in the retrieval coefficient to account for the shift in the NOAA-21 spectral response function compared to Suomi NPP and NOAA-20. This baseline VIIRS I-band active fire product is planned to continue in operations for the next few years when it will be replaced by the VIIRS capability within NOAA’s Next Generation Fire System (NGFS). While the baseline product was developed to minimize commission errors, NGFS is aimed at the detection of smaller fires earlier after onset, and detection and FRP retrieval for all-weather conditions. Comparisons between the baseline and NGFS test data are ongoing and have shown advantages of the NGFS algorithm in particular in the presence of cloud cover or thick smoke. These features also are expected to improve FRP input into NOAA’s emission modeling systems, resulting in improved smoke and air quality monitoring and forecasting.