近40年阿拉善高原大风天气时空分布特征

以l96l-2000年阿拉善高原10个气象站气象记录为主要数据源,运用气候统计学方法,对阿拉善高原40年大风天气的时空变化特征及其区域差异,结合地形地貌和大尺度天气系统变化,导致大风天气自然环境进行了分析。分析结果表明:大风天气高值区位于阿拉善高原的西部,从年内分布看,研究区年内大风天气集中于4~7月,占全年大风天气的54.3%,3月和8月次之,占全年的18.0%。从年际变化看,阿拉善大风天气年际变化的共同特点是:20世纪60年代大风天气是逐渐上升的,70年代或80年代达到峰值,90年代逐步下降,90年代为40年来的最小值。阿拉善高原大风天气受全球气候变化、大尺度天气系统及局地地形和下垫面性质的影响,沙尘天气多发期与反厄尔尼诺事件和干冷气候期相对应。

Spatial - temporal distribution characteristics of windy weather in recent 40 years in Alxa Plateau, Inner Mongolia

Based on meteorological data of 10 stations in Alxa Plateau from 1961 to 2001,employing climate statistics methods and geographic information sciences(GIS),the data about windy weather have been analyzed to get a comprehensive knowledge of spatial-temporal distribution of windy days in Alxa Plateau and to further understand their changing features in the past 40 years and recent tendency.The annual number of windy days was selected as the major index to divide the region into two districts,then the geo-environmental background was analyzed based on the data of landform and land cover.This research demonstrated the spatial distribution and temporal changes of windy weather in this area,leading to the following conclusions:As for the spatial distribution,the high frequency regions were located in the extensive Gobi in the west.Seasonally,late spring and early summer(from April to July) were the windy weather most easily happening periods.Interannually,the features on frequency variation of windy weather in recent 40 years are as follows: a fluctuating increase during 1960s,a high frequency period during 1970 or 1980s,after that time,a fluctuating decease during 1990s and is the minimum in 40 these years.Changes in the number of windy days in Alxa Plateau are the reflections of periodical change in climate.The windy weather is the results of the special geographic environment and weather conditions.The high frequency windy weather took place in the year that anti-El Nino cases were at the top and the dry and cold climate.