Global 2km×2km low uncertainty column-averaged dry air mixing ratio of methane dataset (2018-2025)

TROPOMI is one of the highest resolutions (5.5km× 7km) payloads capable of daily observation of global CH4 columns to date, while the native resolution of tens of square kilometers remains falls short in capturing point sources and emission plumes at smaller scales (e.g., <10 km²).

We report a global 2km×2km low uncertainty column-averaged dry air mixing ratio of methane (XCH4) dataset (2018-2025) version 1.0 (referred to as TRCH4S V1.0), produced by Level-2 TROPOMI CH4 product using our regridding algorithm, including monthly, seasonally, and annual products. TRCH4S is in good agreement with correlative measurements from the TCCON, with R=0.953 (higher than 0.78 of the L2 CH4 product), RMSE=12.39ppb, BIAS= -1.09 ± 12.36 ppb (-0.06 ± 0.66%), less than the mission requirement of 1.5% bias, and cross-validation with GOSAT observations confirms robust spatiotemporal consistency, with R=0.892 (higher than 0.83 of the L2 CH4 product), RMSE=18.93ppb, BIAS=-6.24 ± 17.88 ppb (-0.33 ± 0.95%), less than the mission requirement of 1.5% bias, demonstrating good fidelity in capturing spatial hotspots and low-concentration regions.