一次东北地区暴雪的数值分析

Numerical Analysis of a Snowstorm Event in Northeast China

利用UNIDATA高精度0.5度×0.5度的分析资料,对2009年2月12日至13日东北地区的一次暴雪过程进行了模拟和分析。结果表明:这次暴雪过程是处于有利的高低空急流的配置下产生的;对流层中下层的正涡度、辐合,高层的辐散和深厚的强烈上升运动,为这次暴雪过程提供了很好的动力条件;低空急流对水汽输送起到了至关重要的作用,低空急流维持及其迅速加强和南北二支高空急流的分支和稳定维持、高低空急流的相互耦合很可能是这次暴雪天气过程的发生和发展机制。

By using the Unidata data set which has a 0.5×0.5 horizontal resolution,a snowstorm event,occured from February 12 to 13 in 2009 over Northeast China,was simulated and analyzed in this paper.Some results were found as follows: this snowfall occurrd under the background of upper and lower weather system matched very well.The positive vorticity and convergence in the middle and lower of troposphere and divergence in upper troposphere were all favorable dynamicl condition which cause the air mass ascending vigorously.The role of lower tropospheric jet stream from wet regions was very important for vapor transport.Both the lower tropospheric jet stream and two branches upper tropospheric jet streams sustained,strengthened and coupled with each other may be a main factor benefit for this snowfall occurred and developed.