Methane retrievals and emission estimates of localized sources from EnMAP and EMIT space-borne data

Anthropogenic emissions of methane (CH₄) are the second-largest anthropogenic source of greenhouse gases after carbon dioxide (CO₂) and are a major driver of climate change. Rapid reductions in emissions would help reduce near-term warming. Analysis of satellite data provides information on methane emissions from important localized methane sources such as landfills and fossil fuel extraction sites. This information is used to identify emission sources, quantify their emissions, and monitor progress in reducing emissions. However, this application requires careful analysis of the satellite data because extracting reliable information on atmospheric methane concentration variations and emission estimates from the measured radiance is not trivial, as the measured radiance is affected not only by methane but also by many other interfering effects, including clouds and surface features. Several ESA (GHG-CCI, MEDUSA, SMART-CH4) and EU (EYE-CLIMA) projects focus on the further development of the algorithms needed for reliable emission detection and quantification. This includes the application of the algorithms to several important methane sources and intercomparisons with results from other groups using independently developed methods. In this context, we are developing the HighResolutionFit (HiFI) package, which implements several methods to retrieve atmospheric methane information from high-resolution satellite sensors such as EnMAP and EMIT. The corresponding atmospheric data products are used to obtain emission information using a Cross-Sectional Flux (CSF) method. Here we present the latest status of these activities, including comparisons with corresponding results from other groups.