【摘要】 本文针对1973年5月27日我国西北部的一条天气尺度的冷锋前颮线,研究了当它自西北向东南移过北南走向的六盘山脉时,山脉对天气系统的影响。分析表明,此颮线向南推进的速度,在六盘山脊区比其东西两侧慢,在相距100公里的同一纬度上,最多时差可达二个小时 ;在颮线向南的推进过程中,六盘山脉两侧的单站诸要素变化甚大,各站的变化峰值的出现时刻,也表现出自西向南的后延现象,而在山脊区则无此特点。更多还原

【Abstract】 A synoptic-scale squall line ahead of a cold front occured over North-West region of China on May 27, 1973. This paper is a case study about the topographic effect of Liu-Pan-Shan Mountain on the synoptic system when the squall line moved from northwest to southeast over the Mountain which extends from north to south. It is found that the velocity of the squall line moving over the Mountain ridge southerly is lower than that along the both sides. The maximum time lag between the Mountain ridge and its two sides for a distance of 100 km and at the same latitude may reach to two hours. During the process, when the squall line moved southerly, the changes of meteorological elements for stations along the both sides of the Mountain are very large, and the time at which the peak value occures shows a time lag from North to South, but there is no such lag over the Mountain ridge.更多还原