湖南地区雨雪冰冻过程中的高空急流演变特征

Characteristics of the Upper-Level Jet Stream of the Freezing Disaster Event in Hunan

利用国家电网公司架空输电线路覆冰观测数据、中国气象局738个台站观测数据和NCEP/NCAR再分析资料,挑选出2008年以后湖南地区5次严重的雨雪冰冻过程,对雨雪冰冻过程期间高空急流的演变及影响进行了分析。结果发现,1)雨雪冰冻事件开始前—发展—结束过程中,高空急流存在增强—强盛—减弱的演变过程,其中温带急流强度增强与中高纬度阻塞高压密切相关,副热带急流强度增强对低空急流有影响。2)温带急流增强与冷空气活动密切相关,雨雪冰冻过程前温带急流的2次突然增强对应着北方地区冷空气南下的2个阶段;副热带急流增强与暖湿空气活动密切相关,雨雪冰冻过程前副热带急流2次强度增强对应着南方地区的2次增温过程。

Based on the daily observation icing data of transmission lines,the daily meteorological observation data from 738 China stations and the daily NCEP/NCAR reanalysis data,five freezing disaster events were selected since 2008 and effects of the upper-level jet stream on the freezing disaster events were discussed.It was found that the process of the beginning-developing-ending of freezing disaster event corresponded with the process of enhancing-maturing-weakening of upper-level jet stream.The increase of the temperate upper-level jet stream was closely related to the mid-high latitude blocking high,and the enhancement of subtropical high could affect the low-level jet stream.Further analysis indicated that enhancement of temperate jet stream was closely related to the cold air activity,and the enhancement of subtropical jet stream was closely related to the warm and wet air activity.