Quantifying Burn Area of Wildfires from Satellite Active Fire Detections

Abstract:

Previous studies have found that current methods for estimating burned area of fires from VIIRS/NPP Active Fire 375m data (VNP14IMG) often do not provide an accurate estimate for a variety of reasons including meteorological (e.g., clouds) and geographic conditions. Temporal offsets between satellite overpasses and aircraft observations present an additional complication when evaluating satellite-based burned area during periods of extreme fire growth. Accurately estimating burned area from satellites is key to improving emission models and for studying fire evolution. In this work, we develop a novel algorithm to estimate hourly burned area based on drawing the boundary of a polygon containing the accumulated VIIRS detects and computing the area of the polygon. In addition, an hourly timeseries can be created by combining VIIRS estimates with estimates from GOES-17 Active Fire 2km detects obtained with the same method. Results show an accurate estimate for hourly accumulation of burn area for the 2019 Williams Flats Fire when compared with airborne observations (NIROPS). Analysis includes the VIIRS instruments aboard S-NPP and NOAA-20, with a focus on sensitivity induced by changing the convexity of the polygon drawn. Comparison to other methods used for computing burned area will also be included.