Details zum Stellenangebot Nr. 254
Molecular absorption line-shapes and their impact on satellite CO2 and CH4 measurements
|Arbeitsgruppe||Fernerkundung von Treibhausgasen|
|Kontakt||Prof. Dr. André Butz ; Tel 54 6310|
Beschreibung:Greenhouse gases: Man-made emissions of the greenhouse gases carbon dioxide (CO2) and methane (CH4) drive contemporary climate change. While the rising atmospheric CO2 and CH4 concentrations in the Earth’s atmosphere are evident, our knowledge on how sources and sinks act on regional-to-local scales and how they evolve in the future under climatic and societal change is highly uncertain. To reduce these uncertainties, it requires advanced observation techniques, data reduction methods, and modelling tools that enable attribution of the minute atmospheric concentration gradients to the driving processes of the carbon cycle and human activity. Project: Current satellites such as NASA’s OCO-2, the Japanese GOSAT, and the European Sentinel-5 Precursor measure the CO2 and/or CH4 concentrations in the atmosphere with high accuracy. Our group has developed a retrieval algorithm that is in routine operation for these satellites. Recent spectroscopic analyses taking into account subtle effects such as line-mixing and speed-dependence point to deficiencies in the absorption line shapes used for greenhouse gas retrievals. Here, we propose to implement a new spectroscopic line-shape model and to test its impact on the quality of satellite-derived greenhouse gas concentrations Tasks: • Learn how to operate the satellite retrieval algorithm and make yourself familiar with the relevant radiative transfer and spectroscopic line-shape theory. • Implement the current generation of spectroscopic lineshape models in a stand-alone software tool that generates look-up tables for the CO2 and CH4 absorption crosssections used by the satellite retrieval. • Quantify the impact of the refined spectroscopic model on the quality of the satellite-measured greenhouse gas concentrations, estimate the impact on source/sink estimation. Requirements: • Keen interest in atmospheric radiative transfer, molecular physics, absorption spectroscopy. • Hands-on approach to programming scientific software.
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