2009年1月21～23日西北区寒潮天气过程分析

利用常规气象观测资料、NCEP/NCAR 1°×1°再分析资料等,采用天气学原理和方法,对2009年1月21～23日发生在西北地区的一次寒潮天气过程的影响系统配置、冷空气移动路径及高低空环流形势演变和物理量特征进行了分析。结果表明,这是一次"横槽转竖型"寒潮过程,冷空气路径属西北偏北型,有强冷空气在西西伯利亚及贝加尔湖堆积并向南侵袭造成的。物理量的诊断分析发现,正涡度输送对寒潮爆发有一定的作用;冷平流强度强,从温度平流的垂直结构来看,冷平流中心在700 hPa,冷空气主要集中在底层;水汽条件较差,所以降水较弱;地面正负3 h变压差达6 hPa,利于产生变压风,造成大风天气。

Analysis of A Cold Wave Weather Process in Northwest Area on January 21-23, 2009

Using the routine meteorological observation data,NCEP /NCAR 1° × 1° reanalysis data,etc,adopting synoptic meteorology principle and methods,the influenced system configuration,cold air path and changing circumstances of the high and low air circulation,and physical characteristics of the cold wave weather process in northwest area on January 21-23,2009 were analyzed.The results showed that this is a " horizontal groove turning the shaft type" cold wave process,cold air path type belongs to the north by northwest,strong cold air accumulation in western Siberia and Lake Baikal going south caused the cold wave.Through the analysis of the diagnosis of physical quantities,positive vorticity transport having certain effect of cold wave broke out was founded.If the cold advection is strong,from the perspective of the vertical structure of the temperature advection,cold advection center at 700 hPa,cold air is mainly focused on the bottom;Water vapor condition is bad,so precipitation is less.Plus-minus surface pressure variation in 3 hours was up to 6 hPa,which is beneficial to produce allobaric wind,then formed the strong wind weather.