气候因子对内蒙古沙尘暴频率的影响

利用内蒙古中西部地区40年(1961～2000年)的气象资料、沙尘暴资料和气候资料,讨论了内蒙古中西部地区沙尘暴频率变化趋势和气候动力因子对沙尘暴频率的影响.结果显示:近40年期间,内蒙古中西部地区沙尘暴日数有明显的减少趋势,沙尘暴频率总体上减少的主要原因是影响沙尘暴频率趋势的气候动力因子,也就是代表冷空气活动的气候因子周期变化所致.影响内蒙古中西部地区沙尘暴频率时间分布变化的气候主导因子是:大风日数、北半球极涡面积指数、亚洲北半球极涡强度指数等代表冷空气活动的气候动力因子.

Impacts of Climatic Factors on Dust Storm Frequency in the Inner Mongolia of China

Meteorological dust storm frequency data from 37 stations of 40 years (1961-2000) throughout the west-central Inner Mongolia of China are analyzed together with climatic factors of 40 years in this region. The results show that dust storm frequency in this region has taken on a decline trend during the period of 1961-2000 and the trend of dust storm frequency is determined by the dynamical parameters rather than the factor of land cover condition. The main climatic factors controlling dust storm frequency in this region are the number of days with gale, intensity index of the northern hemispheric polar vortex, and intensity index of Asian polar vortex which are good representatives for large-scale cold air activities. The explanation for the decreasing trend is that it is mainly due to the variation in climatic factors determining dust storm frequency in the Inner Mongolia of China.