Towards high-resolution CH4 simulations for tropical South America: a preparatory study for the CoMet 3.0 mission using ICON-ART

Methane (CH₄) is a key greenhouse gas contributing to global warming, therefore a comprehensive understanding of its sources, sinks, and feedback mechanisms is essential for budgeting of emissions. However accurate methane apportionment, especially for emissions form natural sources (e.g. wetlands) remains a challenge, particularly in tropical regions where emissions from wetlands are highly uncertain. Contributions from human activities are generally better understood, however there are still areas where additional information or methodology improvements would be relevant.

The upcoming CoMet 3.0 Tropics mission (July-August 2026) aims to reduce these uncertainties through intensive airborne measurements of CH₄ and CO₂ aboard HALO (High Altitude and LOng range research aircraft) over Brazil, targeting tropical wetlands and anthropogenic hotspots.

To support mission planning and interpretation, a regional modeling framework based on ICON-ART is developed, configured in limited-area mode (LAM) over Brazil at ~6.5 km resolution (R03B08 grid). The model is driven by ERA5 meteorology and CAMS inversion-optimized CH₄ fields (v22r2), with anthropogenic emissions from EDGAR v8.0 and wetland emissions from WetCharts v1.3.3.

Here, we present a simulation for August 2022 serving as a methodological testbed for the modeling system. This work demonstrates the feasibility of high-resolution CH₄ simulations in tropical South America using ICON-ART and provides a foundation for future analysis of the results from CoMet 3.0 Tropics mission.