近50年中国大范围持续性冰冻天气过程的变化特征

Change Features of the Extensive and Persistent Ice-freezing Processes of China in Recent 50 Years

定义了一种大范围持续性冰冻、雨凇和雾凇天气过程的识别方法,并基于该方法识别出了1954-2009年中国60个大范围持续性冰冻天气过程、28个大范围持续性雾凇天气过程和19个大范围持续性雨凇天气过程。雾凇天气过程主要出现在中国北方地区;而雨凇天气过程集中在江南一带。大范围持续性冰冻、雨凇、雾凇天气过程均在20世纪80年代末期以后出现了突变减少,在90年代初至21世纪初几乎没有出现该类过程。气候变暖可能是大范围持续性冰冻天气过程减少的重要原因。受气温升高影响,中国冰冻天气过程的持续性减弱、影响范围缩小,导致大范围持续性冰冻天气过程出现的频次减少,易于出现持续时间更短、影响范围更小的过程。

A method was improved to identify the extensive and persistent ice-freezing, glaze and rime processes of China during recent decades based on the datasets of daily ：glaze and rime observations from 740 stations of China from 1 January 1954 to 31 December 2009. And then, frequencies, durations and extent of influence of these processes were analyzed. 60 extensive and persistent ice-freezing processes and 28 （ 19 ） extensive and per- sistent rime （glaze） processes were identified, which mainly occurred in December, January and Feburary. The extensive and persistent rime process mainly occurred in northern part of China, while the glaze process was al- ways observed in the area to the south of the Yangtze River. Extensive and persistent ice-freezing, rime and glaze processes decreased significantly after late 1980s, with few processes being observed during early 1990s to early 21 st century. Climate warming may be an important reason for the decreases. As increases of the tempera- ture, the persistency of the ice-freezing weather weakened and the impacting extent narrowed, causing extensive and persistent ice-freezing processes being replaced by regional or local processes with shorter durations.