西藏聂拉木2013年2月暴雪天气气候特点及其成因分析

Climate Characteristics and Its Causes of Snowstorm in Nyalam of Tibet in February 2013

利用常规观测资料和Micaps数据,分析了聂拉木建站以来同时期降雪量达最大的2013年2月的天气气候特征,对月内出现的3场暴雪天气过程从环流特征、影响系统、各物理量、卫星云图以及地面要素的相应变化特征等方面对其成因进行详细分析,总结环流形势及影响因素的共同特征和不同点。结果表明,3场暴雪主要影响系统均为南支槽,是北部强冷空气与南支槽前的暖湿气流共同影响的结果。中高纬槽脊、南支槽、高空急流以及低纬度两副热带高压的位置、强度以及持续时间的不同,造成了3场过程降雪强度、影响落区以及持续时间的差异。

Using the conventional observation data and Micaps data,the weather and climate characteristics of February 2013,which had the largest amount of snowfall during the same period since the construction of Nyalam, were analyzed. The causes of the three snowstorim weather processes occurring during the month were analyzed in detail from the aspects of circulation chaties, satellite cloud maps and corresponding changes of ground elements , the common features andinfluencing factors were summarized. The results showed that the main impact systems of the three snowstorms were the south branch troughs,which was the result of the combined influence of the strong cold air in the norMiddle and high latitude ridge,soutli branch trough,high altitude jet and the location,intensity and duration of tat low latitudes resulted in differences in snow intensity,impact area and duration over the three periods.