Estimating source strengths and lifetime of Nitrogen Oxides from satellite data

Abstract

Over the last hundred years, the chemical composition of the atmosphere has changed significantly due to anthropogenic emissions. Nitrogen oxides (NO+NO2) play an important part, as they directly affect human health and environment, and are involved in chemical key reactions, leading to ozone production in the troposphere. Spectral measurements from satellite platforms of the light reflected by the earth allow the retrieval of several trace gases, e.g. NO2. In this thesis, the spectra of the satellite instruments GOME and SCIAMACHY were used to determine tropospheric column densities of NO2. The resulting dataset, comprising eight years with global coverage, allows the identification, characterization and quantification of the different sources of nitrogen oxides. In this way different anthropogenic sources as well as lightning and biomass burning could be studied separately and partly be quantified. The spatial resolution of the GOME successor SCIAMACHY allows furthermore the unequivocal localisation of individual sources like large cities or power plants. This helps to improve spatially resolved emission inventories. Finally, the satellite data has been used to estimate the mean lifetime of nitrogen oxides in the troposphere for different regions and seasons. For the first time, this allows to compare measured and modelled lifetimes on a global scale.