北极涛动与我国北方强沙尘暴的关系

使用1954—2003年北极涛动指数、500hPa纬向环流指数和沙尘暴等气候观测资料，针对我国北方春季沙尘暴年际和年代际变化趋势，分析了以北极涛动为代表的大气环流异常变化的气候特征，揭示了其与我国春季沙尘暴相关的事实。结果表明：近50年北极涛动指数表现出由负位相向正位相转变的趋势，当冬季(12月～2月)北极涛动为负位相时，相应的纬向环流指数为负距平，中高纬度西风气流偏弱，有利于极地冷空气向南输送，西伯利亚高压偏强，我国北方春季易多发区域性沙尘暴；反之则不易发生区域性沙尘暴。

Relationship between Arctic Oscillation and Spring Severe Sandstorm in North China

The historical climatic data such as the sandstorm frequency and intensity, the Arctic Oscillation index(AOI), the zonal circulation index on 500 hPaand the intensity of Siberia High from 1954 to 2003 are analyzed. First, the variation tendency of sandstorm is analyzed, it is a climate phenomenon in spring. Secondly, the sandstorm in spring is a response to AO and the relationship between the atmosphere general circulation anomaly are also investigated. The results show that when the Arctic Oscillation is negative episode in winter, correspondingly, the zonal circulation index exhibits negative anomaly and the westerly flow in middle and high latitudes weakens, which makes cold air in polar areas to transport southwards and the Siberia High to strengthens, thus results in sandstorm increase, and vice versa Above preliminary results have some novel and applied value for the prediction of the variation tendency of sandstorm in North China.