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

北极海冰在最近急剧减少。根据卫星测量的估计，自1979年以来，北极海冰的下降趋势约为每十年-10%，2007年北极海冰的下降幅度比气候值低38%。相比之下，南极海冰被发现在1978-2006年间每十年增加0.9±0.2%。虽然北极海冰退缩与温室气体浓度增加引起的对流层变暖有关，但极地平流层的化学臭氧耗竭及其对对流层环流的影响已被认为是解释观测到的南极变化的驱动机制。随着温室气体的进一步增加和极地臭氧在21世纪末的预期恢复，我们希望通过应用一个新的大气-海洋化学-气候模式（AO-CCM）来评估海冰和平流层臭氧在现在和未来极地表面气候中的相对作用。通过包括相互作用化学和海洋/海冰模块，AO-CCM使我们第一次能够解释平流层成分变化、海洋-海冰系统和气候之间的反馈过程。我们将研究a)过去和未来平流层臭氧变化对海冰和极地气候的影响，b)气候变化引起的海冰变化对对流层和平流层的影响，特别是对平流层臭氧的影响。将特别注意北极和南极的差异。

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.