影响广西两次低温灾害及物理机制对比分析

Comparison Analysis of Two Low Temperature Disasters and Physical Mechanism in Guangxi

利用常规观测资料、NCEP再分析资料对比分析了2016年1月23-28日和2008年1月13日至2月5日影响广西的两次强冷空气的灾害特征、环流形势,动力机制。分析表明:2016年强冷空气过程阻塞高压比2008年冷空气过程的高压异常偏强。2016年1月冷空气过程中高纬度环流为两槽一脊型,强冷空气沿西路迅速南下,导致广西近50年最南雪线。而2008年1月强冷空气天气过程,中高纬度维持稳定的东高西低形势,冷空气东路南下影响,导致广西近50年最长期的冻雨和冰冻天气。负涡度往乌拉尔山东部高压内部持续输送,支持了2008年1月阻塞高压不断重建、维持。2008年冷空气过程因为孟加拉湾水汽持续输送,维持了长期冻雨和冰冻天气,2016年冷空气过程由于水汽不足,导致少量降雪过后迅速转晴天。

Based on the conventional observation data and the NCEP reanalysis data the low temperature disaster,circulation,dynamic mechanism and water vapor characteristics are investigated and compared between the strong cold air course in January 23-28,2016 and the cold air course in January 13-February 5,2008.The analysis results shows that the blocking high pressure in 2016 strong cold air process was abnormal stronger than that of cold air process in 2008.The middle-high latitude general circulation of cold air course in January 2016 belonged two troughs and one ridge pattern.The strong cold air moved south along the Westly road quickly,led to the most southerly snow line in the last 50 years in Guangxi.And the middle-high latitude general circulation of cold air course in January 2008 maintained stable East high-West low situation.The strong cold air moved south along the Eastly road quickly,led to the most prolonged freezing rain and freezing weather in Guangxi in the last 50 years.The transporting of negative vorticity continues to the eastern part of the Ural Mountains region supported the blocking high-pressure reconstruction and maintenance in 2008.Transporting water vapor from the Bay of Bengal led to long-term freezing rain and frozen weather in cold air course in 2008 in Guangxi.The lacking of water vapor in cold air course in 2016 resulted in a small amount snowfall and turned sunny quickly.