【摘要】 2 0 0 1年 4月 ,兰州地区连续出现了两次区域性强沙尘暴天气。文中从天气概况、气候背景、地面和高空环流形势等方面 ,对两次沙尘暴天气进行了分析。结果表明 ,两次沙尘暴天气过程是在同样的大尺度环流背景下产生的 ,都是由冷锋后偏北大风引起的。但由于造成两次沙尘暴天气的冷空气强度、锋区南压程度、冷空气移动路径等不同 ,因此造成两次沙尘暴天气影响范围、强度也有所不同。同时 ,兰州地区 2 0 0 1年冬季气温异常偏高 ,春季降水偏少以及本地区特殊的地理、地形环境 ,加剧了大风、沙尘暴的出现频次和强度。通过分析 ,初步总结出了此类天气的预报思路和要点。更多还原

【Abstract】 The two cases of regional severe strong sand-storm synoptic processes which occurred in Lanzhou on 8 and 29 April, 2001 are analyzed respectively according to the aspects of synoptic system, climatic background, underlying and upper air circulation situation. The results show that both the two sand-storm synoptic processes resulted from either the same large scale circulation background or the whole northern gale behind the cold front. But the range and the path of cold air and the southward moving cold front are different, thus results in the area of coverage and the intensity of the both sand-storm synoptic processes are also different. Meanwhile, because of the abnormally high temperature in winter, the lack of precipitation in spring and the specific geographic or topographic environment, the frequency and the intensity of the gale and sand-storm are aggravated. The predicting technical train of thought and the main points of these sand-storm synoptic processes are preliminary summarized.更多还原