Estimation of methane emissions using TROPOMI and divergence analysis: A top-down assessment of Ghana’s national-scale methane budget

Abstract Methane (CH4) emissions play an increasingly significant role in the climate impact of developing countries. Especially in Sub-Saharan Africa, where rapid population growth, expanding agricultural activities, and intensifying land-use change are altering emission patterns. These translate to severe implications for climate change, yet large uncertainties remain in the spatial distribution and emission sources in this region. We quantify methane emissions in Ghana using column-averaged methane observations from the Sentinel-5P TROPOspheric Monitoring Instrument (TROPOMI) combined with a divergence-based analysis. The observations were gridded, incorporated with wind vectors, and analyzed to characterize background concentrations and identify spatial patterns indicative of emission sources. Multi-year atmospheric methane concentrations, surface and background levels, defined using the 10th percentile of observations, reveal relatively high concentrations in the southern part of the country. Methane fluxes exhibited strong directional asymmetry, with wind components indicating predominantly westward and southward transport. We inferred emissions, with most areas below 35 kg/km2/h, attributable to emissions consistent with agricultural sources and mixed anthropogenic activities. The results reveal few but distinct methane emission hotspots with clear spatial structure over areas, highlighting contributions from both biogenic and anthropogenic sources. Validating the satellite-derived estimates with the Emissions Database for Global Atmospheric Research (EDGAR) showed an underestimation of the inventory. This approach demonstrates the capability of satellite-based methane observations, coupled with divergence analysis and inventory-based comparison, to support large-scale monitoring and assessment of methane emissions in data-scarce regions, providing a framework for improving constraints on regional methane budgets.