Carbon dioxide (CO₂) and methane (CH₄) are the two most important anthropogenic (man-made) greenhouse gases and contribute to global warming. Despite their importance, our knowledge has significant gaps, especially concerning their natural and anthropogenic sources and sinks. The spectroscopic measurements of the SCIAMACHY instrument onboard the environmental satellite ENVISAT enable for the first time to globally map the atmospheric concentrations of both gases including their near-surface variations where their source/sink signal is largest. As sources and sinks only result in small variations on top of a large background signal, the accuracy requirements are challenging (~1%). So far “only” three years of data (2003-2005) have been processed and the analysis of this data set is still ongoing. The focus of this PhD research project will be to further improve the retrieval algorithm to further enhance the accuracy of the greenhouse gas data products and to process and analyse more data (2006 and beyond). This work will be performed in cooperation with many national and international partners who provide, for example, independent ground-based measurements and knowledge about global model data sets. The ultimate goal of this research project is to improve our knowledge about the sources and sinks of the two greenhouse gases and therefore covers a broad range of disciplines including physics, biology, and biogeochemistry.