CMIP3及CMIP5模式对冬季和春季北极涛动变率模拟的比较

Comparison of Simulated Winter and Spring Arctic Oscillation Variability by CMIP5 and CMIP3 Coupled Models

结合NCEP再分析资料,评估了28个参加第五次耦合模式比较计划(CMIP5)的耦合模式对1950—2000年冬、春季北极涛动(AO)变率的模拟能力,并与CMIP3模式模拟结果进行了对比。结果表明,尽管CMIP5模式没能模拟出冬、春季AO指数前30年处于显著的负位相期而后20年处于显著的正位相期的特征,但是基本能够模拟出冬、春季AO指数1950—2000年显著的增强趋势以及振荡周期,多模式集合改进了模拟效果。同样,CMIP3模式没能模拟出冬、春季AO指数前30年处于显著的负位相而后20年处于显著的正位相的特征,而且1950—2000年冬、春季AO指数的增强趋势在CMIP3模式模拟结果中也没有表现出来,多模式集合没有改进模式模拟效果。不仅如此,CMIP3模式对AO指数的长期变化周期模拟不好,只是模拟出了冬季周期为2～3 a的振荡,没有模拟出春季AO指数的4～5 a振荡周期。尽管CMIP5模式对冬、春季AO指数的模拟能力还不够理想,没有完全模拟出AO指数的变化特征,但是相对于CMIP3模式,无论是对AO指数变化趋势的模拟还是对其变化周期的模拟,CMIP5模式都有所提高。

This study evaluates the simulation ability of winter and spring Arctic Oscillation （AO） variability carried out with coupled climate models participating in the experiment ＂historical＂ organized by CMIP5. The features ofAO during 1950 2000 in twenty eight models were analyzed and compared with those in the NCEP reanalysis data and twenty two CMIP3 models. The results show that, the significant increasing trend and oscillation cycle of winterand spring AO index can be reproduced by most models although the significant feature that winter/spring AO is in significant negative phase in the first 30 years whereas positive phase in the last 20 years is not shown up in thesimulation, The multi-model ensemble has improved the effect of the simulations by CMIP5 models. As CMIP5, the CM1P3 models can not catch the feature that winter/spring AO is in significant negative phase in the first 30 yearsand positive phase in the last 20 years, what＇s more, the significant increasing trend of winter and spring AO index is not shown up in the simulation by CMIP3 models, and there is not any improvement in the result of multi-modelensemble. There is a poor simulation for the variation cycles of AO index in the CMIP3 models. The oscillations with a cycle of 2 3 years in the winter AO index is reproduced by CMIP3 models, but the spring AO index simulatedby CMIP3 models does not show the oscillation cycle of 4-5 years. Although the simulations are not good enough to catch all the significant features of winter and spring AO indices by CMIP5 models, there are some improvementsnot only for the increase trend but also for the change cycle in the simulations by CMIP5 models relative to CMIP3 models.