Improving on the spatial location of geostationary satellite-derived FRP by accounting for parallax effect

Abstract. When a satellite observes the Earth at an angle, the apparent position of elevated features, such as mountains, clouds or fires in high terrain, can be shifted from their true ground location. This effect, which may be particularly pronounced in the case of geostationary platforms providing observations under systematically high viewing angles in many places, is known as parallax displacement and becomes larger as terrain elevation and satellite viewing angle increase.
Meteosat satellites operated by EUMETSAT provide frequent near-real-time observations that are essential for wildfire detection and monitoring. The new Meteosat Third Generation (MTG) satellites, equipped with the Flexible Combined Imager (FCI), offer improved spatial, temporal and spectral capabilities compared with previous systems. These improvements support better detection and tracking of active fires.
The LSA SAF Fire Radiative Power product (FRP-PIXEL) provides information on the location, timing and radiative energy of active fires, which can be used as an indicator of fire intensity and biomass consumption. However, standard geostationary processing assumes that observed features are located at sea level. As a result, fires occurring in elevated terrain may be incorrectly geolocated due to parallax displacement.
This work presents an updated MTG FRP-PIXEL product that includes both the original fire and terrain-corrected coordinates. The correction aims to improve the spatial accuracy of active-fire locations, especially in mountainous regions. Preliminary comparisons with active-fire information derived from high-resolution Sentinel-2 imagery show that the correction can improve the location of FRP detections over high-elevation terrain.