我国东北地区暴雪形成机理的个例研究
投稿时间: 2004-06-07  最后修改时间: 2005-04-11  点此下载全文
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作者单位
胡中明 南京信息工程大学, 大气科学系, 江苏, 南京, 210044 
周伟灿 南京信息工程大学, 数学系, 江苏, 南京, 210044 
基金项目:国家重点基础研究发展规划项目(G1998040907);中国气象局“九五”青年基金项目
中文摘要:应用NCEP资料分析了2000年1月1—2日发生在我国东北地区的一次暴雪过程。研究表明:这次暴雪发生在两槽两脊的大尺度环流背景下,是高空西风急流和低空西南风急流上下耦合作用的结果。高空急流提供动力不稳定条件,低空急流是暴雪区水汽的提供者和对流不稳定能量释放的触发者;暴雪区还具备上冷下暖热力不稳定条件,暴雪区是北支锋区南压的结果。暴雪区的对流不稳定高度位于850 hPa,湿位涡负值中心与暴雪区有较好的对应关系,由于低空急流对湿位涡的输送,使得暴雪区条件性对称不稳定加强,有利于暴雪的形成。
中文关键词:暴雪  高低空急流  热力结构  条件对称不稳定  湿位涡
 
Case Study on the Genesis of a Snowstrom over the Northeast Region in China
Abstract:The January 2 snowstorm in 2000 in Yinkou,Northeast China is analyzed based on the NCEP 6-hour interval reanalysis data.The analysis shows that the snowstorm occured under the large scale circulation background of two-trough-two-ridge over the Eurosian continent,and resulted from the coupling of the upper level westerly jet and the low level southwesterly jet.The upper-level jet created the dynamic instability condition and the low-level jet played the vapour provider of the snowstorm and the trigger of convective instability energy release.The convective instability layer in the storm stretched from the ground surface upwards to the altitude of 850800hPa,and the snowstorm region has a better correlation with the negative value core of moisture potential vorticity(ζMPV).The transfer of moisture potential vorticity by the low-level jet enhanced the conditional symmetric instability in the snowstorm region,thus favorable for the genesis of the snowstorm.
keywords:snowstorm  high/low level jet  thermal structure  conditional symmetric instability  moisture potential vorticity
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