2008年1月我国南方冻雨过程的热力异常及其形成原因  

Anomalous Thermodynamic Conditions for Freezing Rain in Southern China in January 2008 and Their Cause

作　　者：高洋[1,2] 吴统文[2] 陈葆德[3] 

机构地区：[1]中国气象科学研究院,北京100081 [2]中国气象局国家气候中心,北京100081 [3]中国气象局上海台风研究所,上海200030

出　　处：《高原气象》2011年第6期1526-1533,共8页Plateau Meteorology

基　　金：公益性行业(气象)科研专项(GYHY200806006;GYHY200706005);科技部支撑项目(2007BAC29B03);国家重点基础研究发展计划项目(2010CB951902)共同资助

摘　　要：利用中国604个地面台站的气象观测资料和NCEP 2.5°×2.5°再分析各等压面温度和环流场资料,从地面和大气垂直热力结构配置及其气候异常的角度出发,诊断分析了2008年1月我国南方雨雪冰冻过程的形成。结果表明,冻雨受灾的核心区域约为108°～113°E和25°～28°N范围,在该区域内2008年1月平均地面气温<0℃,相对于常年明显偏低4～6℃,有利于冻雨的形成。同时,冻雨的形成还与大气垂直热力结构密切相关,一方面,由于在850～400hPa之间南方暖湿气流的不断输送,使得850～600hPa之间的平均大气温度明显偏暖,平均气温>0℃,有利于形成降雨;另一方面,在1 000～850hPa之间受北风气流控制,大量的冷空气有利于地面维持持续的低温,导致雨水到达地面后形成冻雨。从年际气候异常的角度来看,2008年1月高层表现出异常强劲的南风,温度较常年明显偏高,低层的北风也强于往年,温度较常年偏低,导致了2008年出现近几十年来少有的雨雪冰冻灾害事件。The snow and freezing rain weather occurred in Southern China in January 2008 is analyzed using the observation data from 604 stations in China and NCEP 2.5°×2.5° reanalysis data from a point of view of the surface and atmospheric thermodynamic structure and its climatic anomaly.The result shows that the core area hit by freezing rain is in the region of 108°~ 113°E and 25°~28°N where the mean surface air temperature is below 0 °C in January 2008,relatively to ordinary year,it is 4~6 ℃ lower which is favorable to form freezing rain.The warm and moist air from Southern China between 850 hPa and 400 hPa continuously transport to make mean air temperature on 850~600 hPa more than 0 ℃,which is favorable to produce precipitation.On the other hand,predominately norther wind on 1 000~850 hPa carrys a great deal of cold air to keep the surface air temperature below 0 ℃,which makes rainfall become freezing while reaching the surface becoming the freezing rain.From the annual climate anomaly,upper southerly and lower northerly are much stronger than the averages,and upper air is far warmer and lower air is far colder than normal.These anomalous conditions in January 2008 are very favorable to occurrence of snow and freezing rain disaster that is historically rare in Southern China.

关 键 词：我国南方 雨雪冰冻天气 热力结构 气候异常 

分 类 号：P426.63[天文地球—大气科学及气象学]