摘要
利用常规观测资料和NCEP 1°×1°及2.5°×2.5°格点再分析资料,对贵州2011年初的低温雨雪冰冻过程的天气成因进行了初步分析。结果表明:东亚地区500 hPa高度距平场"北高南低"分布以及中高纬阻塞高压的稳定维持,有利于引导冷空气频繁南下影响贵州,是持续低温的主要原因。滇黔准静止锋也是重要的影响系统,它的长期存在有利于阴雨天气维持;而大范围的冻雨(雪)天气则是伴随着东移的南支槽以及向上伸展的水汽辐合。由于西太平洋副高较弱和中亚地区低值系统不活跃,没有稳定持续的水汽向贵州输送,所以过程表现出短暂的间歇性,尤其是距离滇黔准静止锋区相对较远的贵州东部地区,受灾程度远不如2008年严重。因为有偏北路径的冷空气入侵,贵州中西部地区冰冻强度超过2008年;垂直结构的差异是影响范围最大强度最强的两次过程(第1和第4次)降水相态不同的重要原因;冰冻的形成与增长是多种气象因子综合影响的结果,在一定的降水条件下,日平均气温是影响冰冻强度的重要因子。
After the extreme freezing catastrophe in year 2008,Guizhou Province experienced another rare freezing weather at the beginning of 2011.Analysis based on the conventional observational data as well as the NCEP reanalysis data indicates that the Ural blocking high and the height departure distribution of ＂negative in the south and positive in the north＂ are the key causes for the maintenance of low-temperature. Meanwhile,the quasi-stationary front in Guizhou and Yunnan plays an important role during the freezing days;the deep trough over Indian Ocean and abundant water vapor are very favorable to the vast area stricken by snow and freezing rain.The extent of calamity is weaker than that of 2008,especially in the eastern Guizhou,as it lacks for the continuous transportation of moisture.The route of cold air mass is also different from 2008.Moreover,the two strong processes are discussed,and they have different configuration in T-logp diagram.In addition,research on the relation among the maximum frozen rain diameter, the daily average surface temperature,lowest temperature,daily total rainfall,the daily mean surface velocity,and the daily average temperature shows a better correlation with freezing development when there has compatible precipitation.
出处
《气象》
CSCD
北大核心
2012年第3期291-299,共9页
Meteorological Monthly
基金
公益性行业(气象)科研专项(GYHY201006010-7)资助
关键词
低温雨雪冰冻天气
灾害
形势特征
锋生函数
冰冻强度
freezing rain and snow weather
catastrophe
characters of synoptic situation
frontogenesis function
intensity of freezing
