Background Suppression in EnMAP Methane Retrieval Maps with a Gated U-Net Denoiser

Kurzfassung

Highlights What are the main findings? A multiplicatively gated U-Net suppresses positive background artifacts in EnMAP methane-enhancement maps while ensuring that the output cannot create or amplify positive signals absent from the raw matched-filter map. On held-out semi-synthetic data, the method reduced mean absolute background enhancement by approximately 80% and the false-positive rate by 72%, while retaining 70.4% of the injected plume-enhancement sum. Weak plume margins remained the main limitation. What are the implications of the main findings? Application to an independent EnMAP controlled-release acquisition retained a coherent enhancement at the documented source while suppressing distributed background texture, providing initial evidence of transfer to real observations. The retrieval-independent, non-amplifying design provides a practical framework for producing cleaner methane-enhancement maps alongside existing retrieval and plume-detection workflows, with broader real-plume evaluation as the next step toward operational use.