近50年中国冬季气温对ENSO响应的时空稳定性分析研究

Stability Analysis in Space–Time on the Response of Winter Temperature in China to ENSO in the Past 50 Years

根据1962-2010年中国160站的月平均气温资料、Nino3．4区海洋Nino指数（ONI）资料以及相应的NECP／NCAR再分析资料，采用相关分析、滑动相关分析、滑动t检验、合成分析等方法，探讨了最近50年中国冬季气温对ENSO响应的时空稳定性问题。结果表明：中国冬季气温异常对ENSO的响应有着显著的地域性差异以及年代际变化，其中东北和西南地区的相关关系不稳定度比较大，而在中国东部地区则比较稳定。东北与西南地区在20世纪70年代中后期以后，冬季气温对ENSO的响应迅速减弱，甚至发生了反向变化，而东部地区这种关系近50年并没有较强的突变。相应的亚洲高空大气环流对ENSO的响应也具有明显的空间差异和阶段性变化，其特征与中国冬季气温对ENSO的响应特征基本对应。从大气环流角度解释中国冬季气温对ENSO的响应发生阶段性减弱的可能机制：ENSO通过经向Hadley环流影响中高纬度大气环流，由于70年代中后期以后亚洲经向Hadley环流的下沉支发生显著减弱，使得东亚大气环流对ENSO的响应减弱，进而导致中国冬季气温对ENSO的响应减弱。

Based on the monthly mean temperature from 160 stations in China, oceanic Nino index （ONI） data from the Nino 3.4 region, and the NCEP/NCAR reanalysis data of 1962-2010, the stability of the response of winter temperature in China to the El Nino Southern Oscillation （ENSO） in the past 50 years is analyzed in space-time by using related analysis, sliding-related analysis, sliding t-test, composition analysis and other analysis methods. These analyses show that the response of winter temperature anomalies in China to ENSO differs significantly with respect to regionality and interdecadal changes. The relationship between winter temperature in China and ENSO is more unstable in northeast and southwest China than in eastern China. In the late 1970s, the response of winter temperature in northeast and southwest China to ENSO declined rapidly, even changing inversely, but remained stable in eastern China without obvious abrupt changes over the 50 years. The response of atmospheric circulation in Asia to ENSO also demonstrates obvious differences in regionality and interdecadal changes, in a pattern similar to the response of the winter temperature in China to ENSO. One possible explanation for the interdecadal change in the response of winter temperature in China to ENSO is atmospheric circulation. ENSO affects atmospheric circulation in the mid-high latitudes by Hadley circulation, which in turn affects winter temperature in China. After the late 1970s, the meridional Hadley circulation in the western Pacific weakened significantly, and as a result, the response of atmospheric circulation in Asia to ENSO also weakened, leading to the obvious decline in the response of winter temperature in China to ENSO.