Ten Years of Near-Surface-Sensitive Satellite Observations of Carbon Dioxide and Methane: Selected Results Related to Natural and Anthropogenic Sources and Sinks

Abstract:

Prior to the recently successfully launched OCO-2 mission, global near-surface-sensitive satellite observations of carbon dioxide (CO₂) have been made with SCIAMACHY/ENVISAT during 2002-2012 and are still being made since 2009 with TANSO-FTS/GOSAT, which also deliver atmospheric methane (CH₄). The SCIAMACHY and GOSAT overlapping time series of atmospheric column-averaged mole fractions, i.e., XCO₂ and XCH₄, now cover more than 10 years. During the last years significant progress has been made in improving the quality of the XCO₂ and XCH₄ data products retrieved from SCIAMACHY and GOSAT and in extending the time series so that more and more applications can be addressed. In this presentation we present some recent results related to CO₂ and CH₄ sources and sinks. The SCIAMACHY products have been generated using retrieval algorithms developed at University of Bremen. For XCO₂ we use an ensemble of data products generated using GOSAT retrieval algorithms developed in Japan (at NIES), in the US (at NASA/JPL and collaborating institutes) and at European institutions (University of Leicester, UK, and SRON, Netherlands, in collaboration with KIT, Germany). Focus will be on three applications: (i) An assessment of the strength of the European terrestrial carbon sink during 2003-2010 based on an ensemble of SCIAMACHY (2003-2010) and GOSAT (2010) XCO₂ data products, (ii) an assessment of CO₂ and NO₂ anthropogenic emission and emission ratio trends using co-located SCIAMACHY XCO₂ and NO₂ observations over Europe, North America and East Asia, and (iii) an analysis of SCIAMACHY XCH₄ retrievals during 2006-2011 over North America focusing on fugitive methane emissions from oil and gas production using tight geological formations (“fracking”). It will be shown that (i) the European terrestrial carbon sink appears to be stronger than expected, (ii) that recent Chinese CO₂ and NO₂ emissions are increasing but with a trend towards reduced NO₂-to-CO₂ emission ratios pointing to cleaner technology in terms of less NO₂ emitted per unit of CO₂ (or unit of energy) and (iii) that the SCIAMACHY satellite-derived methane observations over two fast-growing oil production regions in the United States suggest a significant underestimation in current bottom-up inventories.