冬春季北极涛动与中国中西部地区降水的关系

The Linkage between Winter-spring Arctic Oscillation and Precipitation over Western and Central China

为了研究北极涛动(AO)的变化对中国中西部地区降水的影响,利用1979-2016年CPC的AO指数、降水资料等,运用相关、回归分析等方法对中国中西部降水与AO的关系进行了研究。结果表明:冬春季(1-3月)AO与中国中西部同期降水的相关关系显著,区域Ⅰ(40°N^45°N,70°E^82°E)内相关系数最高达-0.47,区域Ⅱ(17°N^42°N,97°E^117°E)内相关系数最高达0.67。冬春季AO与滞后期降水的相关性随时间减弱,且两个区域的滞后性并不一致,区域Ⅰ的显著相关关系至7月完全消失,区域Ⅱ的显著相关关系至4月消失。AO通过控制极涡、西伯利亚高压等天气系统,影响东亚冬季风及中高纬风场,造成该地区水汽输送及冷空气路径发生改变,进而改变中国中西部降水分布。AO可以对中国中西部降水预测提供有用信号。

Based on the CPC Merged Analysis of Precipitation(CMAP) datasets, Arctic oscillation(AO) index from 1979 to 2016, the influence of AO on the winter-spring(January to March) precipitation corresponding over western and central China are studied.The results show that:There is a significant correlation between the winter-spring AO and the precipitation, but the relativity of AO and precipitation weaken in the long window.In the years of strong AO index, the precipitation declines over the regionⅠ(17°N-42°N, 97°E-112°E), and the precipitation increase over the regionⅡ(40°N-45°N, 70°E-82°E).When the AO is enhanced, the Siberian high and the Polar vortex are enhanced, and the wind field and humidity field in east Asia also change.In the end, it affects the precipitation distribution over western and central China. The winter-spring AO is closely related to the precipitation, and it can provide useful signal for the forecast of precipitation over western and central China.