极地平流层位势高度变化与中国冬季气温的关系

The Relationship Between the Geopotential Height in Stratosphere and the Temperature of China in Winter

平流层异常对于对流层的影响研究,尤其是将平流层的异常信号加入中长期天气预报已成为近年来的研究热点。首先利用NCEP/NCAR再分析资料和国家气候中心提供的160站气温资料,采用SVD方法深入分析平流层位势高度场与中国冬季气温的关系。结果表明,极涡与中国东北地区温度有着非常密切的联系。即当中高纬地区位势高度场减弱时(极涡增强),东北地区的温度上升;中高纬地区位势高度场增强时(极涡减弱),东北地区的温度下降。进一步通过挑选出的6个东北亚型强极涡年,6个北美型强极涡年和8个弱极涡年,分别对冬季位势高度场和温度场进行合成分析、小波分析和交叉谱分析。结果发现,东北亚型强极涡和中国东北地区冬季气温的关系最为密切,平流层关键区位势高度场和东北地区地面温度场都有着50天左右的振荡周期,并且关键区位势高度场的季节内振荡有着超前于温度场的特征;北美型强极涡和东北地区温度的联系较小;弱极涡与东北地区温度的关系也不太明显。

The stratospheric anomaly＇ s influence on the troposphere, especially adding it on the Medium-Range Weather Forecasting has been the hot research area. By using the NCEP/NCAR reanalysis data and the 160 station data of China from the National Climate Center, the relationships between the geopotential height of the stratosphere and the temperature of China in winter is analyzed by SVD. The result shows that the polar vortex is significantly re- lated with the temperature of the northeast of China. That is, when the geopotential height decreases （the polar vor- tex is strong） in mid-high latitudes of the northern hemisphere, the temperature of the northeast of China goes up, and vice visa. Next, the daily geopotential height and the daily temperature are analyzed by the methods of synthe- sis, wavelet and Cross spectrum through the chosen years of the north - east Asian pattern, north American pattern of strong polar vortex and weak polar vortex. A tight connection between the pattern of the northeast Asian polar vortex and the temperature in the northeast of China is found. Both of them have about 50 days oscillation, and the geopotential height is ahead of the temperature as for the intraseasonal oscillation. The North American pattern of strong polar vortex has little relationship with the temperature of China in winter. And the weak one also has little effect on the temperature.