Sea-ice and Stratospheric Ozone - Links and Impacts in the Arctic and Antarctic (ISOLAA)

点击翻译按钮获取中文摘要

Arctic sea-ice has dramatically decreased in the recent past. Estimates from satellite measurements find a negative trend of about -10% per decade since 1979, with a record Arctic sea-ice reduction by 38% below climatology in 2007. In contrast, Antarctic sea-ice was found to have increased by 0.9 ± 0.2% per decade for the years 1978-2006. While the Arctic sea-ice retreat has been associated with the warming of the troposphere caused by increasing concentrations in greenhouse gas concentra-tions (GHGs), the chemical ozone depletion in the polar stratosphere and its effects on tropospheric circulation have been suggested as the driving mechanism to explain the observed Antarctic changes. With further increasing GHGs and an expected recovery of polar ozone at the end of the 21st In this project, we want to assess the relative roles of sea-ice and stratospheric ozone for polar surface climate, now and in the future, by applying a new atmosphere-ocean chemistry-climate model (AO-CCM). By including interactive chemistry and ocean/sea-ice modules, the AO-CCM allows us for the first time to account for feedback processes between stratospheric composition changes, the ocean – sea-ice system and climate. We will study a) the effects of stratospheric ozone changes in the past and future on sea-ice and polar climate and b) the effects of climate change induced sea-ice changes on the troposphere and stratosphere, specifically on stratospheric ozone. Special attention will be paid to differences in the Arctic and Antarctic.