太行山地形对山西两次锢囚锋暴雪影响的数值试验

为深刻认识太行山地形对降雪的影响，做好降雪天气预报服务，从而适应新型农业种植结构调整，减小降雪天气对农业生产的影响，利用NCEP全球再分析资料和实况探测资料，采用WRF中尺度数值模式，对2009年11月10日和2010年3月14日山西省两次锢囚锋暴雪天气进行数值试验，比较分析了太行山地形变化对降雪量级、强度、落区及空间结构特征的影响。结果表明：（1）对于影响系统偏南的暴雪天气，太行山高度适中更能使降雪接近实况，而对于偏北的暴雪天气，则是抬高地形，影响更明显。（2）锢囚锋降雪的不同阶段，太行山地形变化对低层水汽输送的影响差异较大。（3）适当降低太行山高度，使得暴雪区上空高空辐散、低空辐合的垂直结构更明显，中心强度更强，对暴雪的产生更为有利。（4）对于影响系统偏南的暴雪天气，太行山高度降低使得高层干侵入强度增强，造成触发作用加强。

Modeling the Influence of Topography of Taihang Mountains on Two Occluded Frontal Snowstorms in Shanxi Province

The study aims to deeply understand the influence of topography of Taihang Mountains on heavy snow, provide better forecast and service for agriculture production, therefore to adapt to the adjustment of new agricultural planting structure and reduce the influence of snow on agriculture production. The authors used NCEP global reanalysis data and observations, conducted numerical experiments of two occluded frontal snowstorms occurring over Shanxi on November 10 of 2009 and March 14 of 2010 with WRF model, and investigated the impact of topography change of Taihang Mountains on magnitude, intensity, scope and spatial structural characteristics of snowstorm. The results showed that: (1) the simulation with moderate altitude was closer to observations for the snowstorm resulting from southerly influence systems, while the impact of the simulation with increased altitude was more obvious for the snowstorm due to northerly influence systems; (2) during different stages of occluded frontal snowstorm, there was a large discrepancy in the impact of topography change on the transport of low-level moisture; (3) the simulation with suitably reduced altitude made vertical structure of high-level divergence and low-level convergence more obvious and central intensity stronger, which was beneficial for the occurrence of snowstorm; (4) regarding the snowstorm owing to southerly influence systems, the simulation with reduced altitude strengthened high-level dry intrusion and consequently led to the enhanced triggering effect.