Assessing the Potential of the MTG-FCI Geostationary Mission for the Detection of Methane Plumes

The Flexible Combined Imager aboard the Meteosat Third Generation satellite (MTG-FCI) provides geostationary observations over Europe and Africa, the Middle East, parts of South America, and the surrounding waters. The FCI samples the visible, near-infrared, and shortwave infrared spectral windows with a spatial resolution at nadir between 500 and 1000 m, and a 10 min temporal sampling interval. This configuration offers a potential for methane retrievals using multiband multipass retrieval (MBMP) methods, as shown with other multispectral missions. The potential of the MTG-FCI system for the detection and monitoring of single methane plumes is evaluated in this article through different approaches. End-to-end simulations using high-resolution WRF-LES methane plumes over Algeria showed that MTG-FCI can detect emissions as low as 30 t/h, where initial plume signals become visible, with a clearer detection above 50 t/h. Additionally, mass-balance modeling estimated a minimum detection limit of 20-30 t/h across the central MTG-FCI disk (GSD ≤ 1 km) under optimal conditions. We illustrate the use of the MTG-FCI for the monitoring and quantification of methane plumes using a real transient emission detection from a compressor station in Algeria (34.676° N, 6.191° E) on September 29, 2023, capturing its full evolution from 10:48 to 15:58 UTC. This event corresponded to an emission rate of 389 ± 81 t/h and a total methane release of ∼320 tons, with results broadly consistent with independent satellite estimates. These findings highlight MTG-FCI's ability to track large transient methane plumes in near real-time, complementing polar-orbiting sensors.