Institute for Marine and Atmospheric Research (IMAU)

Atmospheric Physics and Chemistry Group (APCG)

 

Ongoing Projects

Inverse modeling of the global sources of methane using satellite instruments

Sudhanshu Pandey

 

Methane is the second most important human produced greenhouse gas, after carbon dioxide. For a reliable forecast of future climate change it is essential to improve our understanding of the global cycle of this gas. Methane is investigated using a ground-based monitoring network and satellite instruments to map the global distribution of methane in the atmosphere. The so-called inverse modeling technique is used to translate these measurements into corresponding emissions at the Earth’s surface. In the case of long-lived greenhouse gases, such as methane, it is a challenge for the satellites to meet the required level of accuracy. The most successful method so far is the so-called proxy method, which makes use of the ratio of methane over carbon dioxide. It is assumed that the contribution of carbon dioxide is well enough understood to use this method for studying methane. However, with the improved measurement quality obtained using the GOSAT instrument this assumption is starting to become an important limitation. The aim of my project is to develop a new method for the interpretation of proxy measurements, in which the ratio is explicitly modeled and the contributions of methane and carbon dioxide are derived separately. This method will be developed and tested using GOSAT and applied to the full time series of SCIAMACHY, which by now covers nearly a decade and provides useful insight in the recent evolution of global methane.