中高纬阻塞环流背景下贵州强冻雨特征及概念模型研究  

Study on the synoptic features of strong freezing rain with blocking pattern in Guizhou and conceptual model

作　　者：杜小玲[1,2] 高守亭[3] 许可 武文辉 

机构地区：[1]贵州省气象台,贵阳550002 [2]贵州省山地气候与资源重点实验室,贵阳550002 [3]中国科学院大气物理研究所,北京100029

出　　处：《暴雨灾害》2012年第1期15-22,共8页Torrential Rain and Disasters

基　　金：国家自然科学基金项目(40930950;40865003)

摘　　要：利用NCEP 1×1、2.5×2.5再分析格点资料以及2000—2009年贵州省冻雨个例资料,对该省12次阻塞环流背景下强冻雨过程的天气学特征进行分析,归纳强冻雨的预报着眼点及概念模型。结果表明:1)强冻雨天气与亚洲中高纬度阻塞环流和中低纬度南支锋区密切联系,位势高度场在20—30 N之间存在4～5条等值线,564～568 dagpm线向南伸展到30 N以南;2)700 hPa上西南急流显著,最大风速达到20～24 m.s-1,其作用在于提供暖湿水汽和逆温顶部的增温效应;3)低空和地面是显著的冷垫,冻雨天气在准静止锋存在的背景下产生,准静止锋又与相对湿度大于70%以上的高湿区相联系,而影响贵州的准静止锋云系,处在锋上的具有暖湿云的特点,锋下的具有冷湿云的特点;4)强冻雨期间,对流层中低空逆温梯度加大,最大可达8～10℃以上。By using NCEP global 1°×1° re-analysis data and 2.5°×2.5°mean re-analysis data,an analysis is made on 12 severe freezing rain events with blocking pattern in Guizhou.The results are as follows.（1） The severe freezing rain is relates to blocking circulation in mid-high latitude over Asia and Europe.Frontal zone in low latitude is favorable for establishment and maintenance of low-level southwest jet offering vapor for freezing rain occurrence and development.The cold air is strong and sustained on the ground.（2） The southwest jet is significant at 700 hPa,which provides warm moist vapor and makes the warming effect strong at the top of the temperature inversion.（3） A cold flow covers minimum altitude and the ground.The freezing rain occurs against the background of a quasi-stationary front which is related to high humidity area with the relative humidity higher than 70%.The quasi-stationary frontal cloud system in Guizhou is characterized by warm-humid cloud on the front and could-humid cloud under the front.（4） In the period of severe freezing rain,the gradient value of inversion in the lower and middle troposphere increases,and maximum gradient value is over 8-10 ℃.

关 键 词：阻塞环流 冻雨 概念模型 

分 类 号：P426.63[天文地球—大气科学及气象学]