基于IPCC AR4耦合模式的南极涛动和北极涛动的模拟及未来变化预估

The Arctic and Antarctic oscillations in the IPCC AR4 coupled models.

中文关键词:  南极涛动，北极涛动，IPCC，耦合模式，环状模

英文关键词:Antarctic Oscillation, Arctic Oscillation, IPCC, Coupled model, Annular mode

中文摘要:

      评估了参加政府间气候变化委员会第4次评估报告(IPCC AR4)的耦合模式对南极涛动和北极涛动的模拟能力。分析了24个模式对1970—1999年南极涛动和北极涛动的模拟效能，并与两套再分析资料ERA-40和NCEP-1进行了对比分析。结果表明，模式的模拟能力具有一定的季节依赖性，冬季模拟能力最好。大多数模式对南极涛动空间结构和时间序列趋势的模拟好于北极涛动。根据Taylor图选出具有较好模拟能力的模式并做集合分析，发现经过选取的模式集合可以明显改善模式的模拟能力。分析SRES A1B情景下的南极涛动和北极涛动的模拟、预估结果表明：1970—2099年，南极涛动和北极涛动指数均呈持续上升趋势，北极涛动指数增长略显平稳。相对于1970—1999年、2060—2089年两半球的海平面气压场均呈现极区气压降低、中纬度气压升高的形态，同样表明南、北极涛动在后一时段更强。因此，在气候变暖背景下，南、北极涛动将持续增强，21世纪中期的臭氧恢复可能不会显著影响这种趋势。

英文摘要:

      This study evaluates the fidelity of Arctic and Antarctic Oscillation (AO and AAO for short, respectively) in the coupled general circulation models participating in the Fourth Assessment Report of Intergovernmental Panel on Climate Change (IPCC AR4). The AO and AAO during 1970-1999 in twenty four models were analyzed and compared with those in the ERA-40 and NCEP/NCAR reanalysis data1. Models' performance is seasonally dependent, with the best reproducibility of both spatial structures and trends in winter. In most models, the spatial pattern and temporal trend of AAO during this period were simulated better than those of AO. After picking out models with better performance according to Taylor diagram, we found that their ensemble mean obviously improved models' reproducibility. The AO and AAO under the Special Report on Emission Scenarios (SRES) A1B Scenario during the 21st century were also briefly analyzed. The results during the period 1970-2099 reveal that both the AO and AAO indices keep increasing during the whole period, with a relatively steadier pace in the AO. The spatial difference in sea level pressure between 2060-2089 and 1970-1999 also shows decreased values in the two polar regions, and increased values in the mid-latitudes. Results also manifest that the ozone recovery in the mid -21st century may not weaken such a trend.