关键词: 河西地区, 大风日数, 时空分布

Abstract: Based on meteorological data of 19 stations in Hexi region from 1959 to 2000, by 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 Hexi and to further understand their changing features in the past forty years and recent tendency. The annual number of windy days was selected as the major index to divide the region into three 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 and high-mountain region in the east. Seasonally, late spring and early summer 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 1959—l963, a high frequency period during 1964—1976, after that time, a fluctuating decease during 1976—1997 and a fluctuating increase tendency after 1997. Changes in the number of windy days in Hexi 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.

Key words: Hexi region, number of windy days, spatial-temporal distribution