Assessing the potential of TROPOMI measurements to improve regional methane emission estimates over India

Methane is emitted by several anthropogenic source sectors, including livestock, oil and gas systems, coal mining, landfills, wastewater treatment, rice cultivation and natural sources such as wetlands. The short lifetime and considerable global warming potential make methane an immediate target for reducing global warming. The existing bottom-up methods relate emissions to source region activities, but significant uncertainties exist when emissions are derived at regional or local scales. In this context, satellite observations of atmospheric methane concentrations can be helpful for improving the inventory information by using additional constraints from atmospheric distributions. In the present study, we use the column-averaged dry-air mixing ratio of methane (XCH4) from  TROPOMI (Tropospheric Monitoring Instrument) on the ESA Copernicus Sentinel-5 Precursor satellite to infer India’s CH4 emissions. We establish the potential of these retrievals to quantify methane emission hotspots and to improve the emission estimates over the Indian subcontinent. The Eulerian model Weather Research Forecast (WRF) coupled with Chemistry (WRF-Chem-GHG) simulations has been used for the forward  transport simulations of atmospheric methane. The inversion studies introduced will enable us to improve the existing anthropogenic emission estimates available in the Indian region.