Impact of ship emissions on climate and atmospheric chemistry

Kurzfassung

Seagoing ships emit exhaust gases and particles into the marine boundary layer and significantly contribute to the total budget of anthropogenic emissions. Ship emissions have been recognized as a growing problem for both scientists and policy makers. Currently they are one of the least regulated sources of anthropogenic emissions with a high reduction potential through technological improvements, alternative fuels and ship modifications. The Junior Research Group SeaKLIM aims at a quantitative investigation of the impact of these emissions on the chemical composition of the atmosphere and on climate. Thus, emission inventories for international shipping for the past five decades and future scenarios until 2050 have been set up for the use in global chemical transport or coupled chemistry-climate models (CCMs). Box model studies are applied to account for the chemical dilution in the near field of a ship, whereas the new CCM ECHAM5/MESSy is used to examine the global impact of aerosols and gaseous ship emissions. In addition to the direct impact of ship emissions on the composition of the atmosphere, particulate matter from ships is known to modify marine stratocumulus clouds under certain conditions. These so-called ship tracks can be detected by remote sensing techniques. Furthermore, NO2 from shipping can be detected by satellite measurements and is subject of further investigations. The talk summarizes recent results of the SeaKLIM group on the analysis of satellite measurements and modeling studies.