河北省一次回流暴雪的数值模拟

应用WRFV3.2.1中尺度数值模式，利用每日4次1°×1°的NCEP-FNL全球分析场资料，对2009年11月9-12日河北省回流暴雪过程进行数值模拟，并利用模式输出的时空分辨率较高的资料，对冷流暴雪特征及其物理机制进行分析。结果表明：暴雪区近地层为干冷气团形成的冷垫，暖湿气流沿锋面上界自低层向高层输送，暴雪的出现与高温高湿能量的输送密切相关，水汽主要来自南方|近地层以辐散和反气旋性涡度为主，上升运动的加强与中尺度对流云团的活动相对应，太行山的地形影响使降水强度加大。

Numerical simulation on a return-flow snowstorm process in Hebei province

Using the WRFV3.2. 1 mesoscale numerical model, a return-flow snowstorm process occurred on No- vember 9-12,2009 in Hebei province was analyzed based on the 1°×1° NCEP-FNL reanalysis data four times a day. The characters of the return-flow snowstorm and its physical mechanism were discussed according to the prod- ucts from the above model. The results indicate that the surface ground is cold cushion generated by dry and cold air mass. The warm-wet airflow transports from the lower level to upper level along the upper boundary of front surface. The occurrence of snowstorm is related with transportation of high temperature and high humidity energy, and water vapor is mainly from the south. Anticyclone and divergence area is main area near the ground surface, and strenBth of ascending motion corresponds to the activities of mesoscale convective cloud mass. The rainfall in- tensity increases because of the effect of topography of Taihang Mountain.