Enhanced methane emissions from Amazonian drought by biomass burning

The Amazon is a significant source of atmospheric methane, but little is known about the source response to increasing drought severity and frequency. We investigated satellite observations of atmospheric column-averaged methane obtained with GOSAT (Greenhouse gases Observing SATellite) for 2010 drought and 2011 wet years using an atmospheric inversion scheme. Our analysis indicates an increase in atmospheric methane over the southern Amazon during the drought, representing an increase in annual emissions relative to the wet year. We attribute the increase to emissions from biomass burning driven by intense drought, combined with carbon monoxide showing seasonal variations correspond to the methane variations. We show that there is probably a strong correspondence between drought and methane emissions in the Amazon. In this study, we also introduce GOSAT Level 4 system of the atmospheric inversion scheme.