Critical analysis of Fire Radiaive Power derived by hyperspectral sensors from space

Fire Radiative Power (FRP) is a quantitative measure of the instantaneous rate of radiant heat energy emitted by a fire during the combustion process. It is usually retrieved via satellite remote sensing and serves as a key indicator of fire intensity and the rate of fuel consumption. FRP is generally estimated by measuring the thermal radiation (radiances) emitted by wildfires, in the Middle Infrared (MIR) spectral range (3.9- 4.0) where the Planck function peaks for sources at 1000K and the contrast between the fire and the cooler background is most pronounced.

A number of satellite imaging systems, at LEO (i.e. MODIS-TERRA and AQUA, VIIRS-Suomi NPP, SLSTR-Sentinel 3A and 3B) and GEO (i.e. SEVIRI-MSG, ABI-GOES, ABI-HIMAWARI) orbits provide FRP retrievals. However, due to their coarse spatial resolution (1-2 km/px) and wide spectral bands, small fires detection and associated FRP retrieval is limited, representing a potential source of omission error.

While currently available high-resolution sensors lack coverage in the Mid-Infrared (MIR) spectral range, recent research has investigated the potential of Short-Wave Infrared (SWIR) sensors as an option. By analyzing airborne data from the AVIRIS, EMAS, and MASTER sensors, studies have established a robust correlation between MIR-derived and SWIR-derived FRP. Furthermore, the SWIR band on Sentinel-3 is already being effectively utilized to estimate FRP for gas flares monitoring.

In this study we retrieve FRP by using two similar hyperspectral sensors, Precursore IperSpettrale della Missione Applicativa (PRISMA) and Environmental Mapping and Analysis Program (EnMAP).  We compare the results with operational FRP products, namely the Sentinel-3 L2 NRT FRP and the CAMS-GOES-W FRP product and evaluate potentials and limitations for mapping the intensity of wildfires and gas flares.