一次暴雪过程地形方案的敏感性试验研究

The sensitivity experiment for a snowstorm by the topography schemes

利用WRF模式中提供的包络地形、轮廓地形和平均地形方案对2005年12月20—21日的山东暴雪过程进行数值模拟。结果表明:地形方案与降雪的时空分布有很大的相关性,地形越接近实际地形,降雪的时空分布越接近实况;降雪过程中有明显的中尺度重力波活动,降雪的峰值滞后于重力波的波峰;重力波受地形影响很大,地形越不平滑,重力波的强度越强、移速越慢;当重力波的强度较强时,降雪峰值滞后于波峰的时间差也较长。

In this paper, the envelope, silhouette and mean topography schemes offered by the WRF model were used to simulate the snowstorm which occurred in Shangdong province during Dec. 20-21, 2005. The result shows that there is a great correlation between the snowstorm space-time distribution and topography, the more actual topography, the more actual space-time distribution. There is significant meso-scale gravity waves in the process of snowfall, the peak value of snow lags behind the wave crest of gravity waves. Gravity waves were strongly influenced by the terrain. The rougher terrain, the stronger the gravity waves and the slower the moving speed. When the strength of gravity waves are strong enough, the time difference that the snow peak lags behind the wave crest of gravity waves becomes quite long.