海温异常对东亚夏季风影响机理的研究进展

A Review of Physical Mechanisms of the Global SSTA Impact on EASM

从短期气候预测关注的外强迫信号角度出发,回顾了国内外在海温异常对东亚夏季风和我国汛期降水影响机理方面的主要研究进展,重点评述了热带太平洋ENSO循环、热带印度洋全区一致型海温模态、热带印度洋海温异常偶极子、南印度洋偶极子和北大西洋海温三极子模态的年际变化及其对东亚夏季风年际变率的影响。从研究成果在短期气候预测业务中应用的角度,重点关注海温异常和东亚夏季风年际变率以及我国汛期降水多雨带位置的关系,总结了海温异常作为外强迫信号对我国汛期降水预测的指示意义以及汛期降水预测的难度。最后指出气候预测业务对东亚夏季风影响的机理研究和动力气候模式发展方面的需求。

The impact of global sea surface temperature anomaly （SSTA） on the East Asia Summer Monsoon （EASM） and summer precipitation in China is reviewed from the aspects of physical mechanisms, on the basis of key external forcing signals in short-term climate prediction. Focusing on E1 Nifio-Southern Oscil- lation （ENSO） cycle in the tropical Pacific and the main SSTA modes in Indian and Atlantic Ocean, their inter-annual variability are further reviewed as well as their different impacts on the EASM, especially their relationship with the main summer rainfall belt in China. During different phases of ENSO cycle, ENSO exerts different impacts on the EASM and the summer precipitation in China. In the developing summer of E1 Nifio, the EASM tends to be weak and the main summer rainfall belt would shift southward in eastern China. However, in the decaying summer of E1 Nifio, the EASM tends to be strong, and the summer precipitation would be below normal in the Yangtze- Huaihe Valley. The situations are approximately reverse for the impact of La Nifia on the EASM and sum- mer precipitation in China, although the impact of La Nifia is not as significant. The influence of ENSO on the EASM and the summer rainfall belt in China is closely correlated with the SSTA in the western Pacific warm pool as well as the resulted convective activities in its northern part. Moreover, the Philip anticyclone also plays an important role. In recent years, different types of E1 Nifio are widely di It is revealed that the Central Pacific （CP） E1 Nifio not only has different evolution mechanisms, shows different impacts on the global atmospheric circulation as compared with the Eastern Pacific Nifio or classical E1 Nifio. pine Sea scussed. but also （EP） E1 Indian Ocean SSTA modes also show significant influences on the EASM and the summer precipitation in China. For example, the basin-wide warming （cooling） mode in the tropical Indian Ocean would cause a late （an early） South China Sea summer monsoon （SCSSM） onset; in the summer of positive （negative） tropical Indian Ocean dipole phase, more precipitation would occur in South China （North China） ; during the positive （negative） phase of subtropical southern Indian Ocean dipole, Indian summer monsoon tends to be stronger （weaker）, and SCSSM may establish earlier （later）. The positive （negative） North Atlantic tri-pole mode would lead to a stronger （weaker） EASM through motivating quasi-barotropic zonal tele-con- nection wave train across the Eurasian continent. summer rainfall anomaly in China. Some advices and requirements on the physical mechanism research and dynamical model development are proposed in order to improve the prediction of the EASM and summer rainfall in China.