东亚夏季海陆热力对比对全球变暖的响应

利用耦合模式比较20世纪气候模拟试验和21世纪SRES(Special Report on Emissions Scenarios)A1B情景气候预估试验结果,探讨了东亚区域海陆热力对比对全球变暖的响应。首先通过超级集合方法,重建了20世纪40a(1960—1999年)和预估了21世纪40 a(2020—2059年)东亚地区的海陆热力对比;在此基础上,分析了东亚夏季海陆热力对比的过去40 a的变化特征及其未来的可能变化趋势。结果表明,超级集合的方法能够有效地降低单个模式存在的不确定性,其结果优于多模式的算术平均结果。利用超级集合方法能够很好地再现1960—1999年间海陆热力差指数的变化特征,并且有效地降低与再分析资料的均方根误差。进一步分析发现,陆面温度在全球变暖背景下变化较明显,尤其在华南地区存在显著增温;而东亚大陆季风区,存在明显的降温趋势。利用超级集合方法预估未来海陆热力对比的结果表明,在2040年前存在较强的海陆热力差,而2050后海陆热力对比有减弱趋势。

Response of summer land-sea thermal contrast over East Asia to global warming

Based on the model results of the 20^th century (The Twentieth-Century Climate in Coupled Models, 20C3M) and 21^st century (SRES A1B scenario) simulations given by the coulpled models anticipated the Phase 3 of the Coupled Model Intercomparison Project (CMIP3), the responses of land-sea thermal contrast over East Asia to global warming are investigated. Fisrtly, the land-sea thermal contrast over East Asia during the periods from 1960 to 1999 and from 2020 to 2059 are reconstructed based on the multimodel super-ensemble method. Then the variation of land-sea thermal contrast in the past 40 years and its future trend are investigated. It is indicated that the result produced by super-ensemble method has higher skill than any individual model and the multimodel ensemble mean. And the analyzed models by using the multimodel super-ensemble can perform well in interannual variations of the index of the land-sea thermal differences from 1960 to 1999, and can effectively reduce the root-mean-square errors compared with the reanalysis data. Further analyses of the land-sea differences over East Asia from 2020 to 2059 show that the change of land skin temperature is remarkable, especially over the south of China, and the regional cooling also exists in Asia monsoon areas. In addition, the marked change in the index of land-sea thermal differences is found before 2040 by using the super-ensemble technique, thereafter the index tends to decrease afterward.