地形对冷流暴雪影响的可能机制研究

Study on Possible Mechanism of Terrain Influence to Cold Airflow Snowstorm

[目的]研究地形对冷流暴雪影响的可能机制。[方法]应用中尺度数值模式(WRF)对一次山东半岛冷流暴雪天气过程进行数值模拟和地形敏感性对比试验,并从水汽、热力场等方面深入分析了冷流暴雪中地形对暴雪落区、强度造成影响的可能原因。[结果]山东半岛山脉地形对冷流暴雪落区、强度影响较大,使其强度明显增大,降雪中心明显北移;而造成影响的主要原因在于地形造成对流层低层风场辐合和垂直运动增强,从而明显改变了冷流暴雪过程中水汽、雪水含量等在空间上的分布,继而影响整个暴雪过程。[结论]山东半岛山脉地形是冷流暴雪天气过程预报分析中需要着重考虑的重要因素。

[Objective] The research aimed to study possible mechanism of terrain effect to cold airflow snowstorm.[Method] By using the meso-scale numerical model（WRF）,a cold airflow snowstorm weather process in Shandong Peninsula was carried out numerical simulation and terrain sensitivity contrast test.The possible reason of terrain effect to falling zone and intensity of snowstorm in the cold airflow snowstorm was analyzed from water vapor,thermodynamic field and so on.[Result] The mountain terrain in Shandong Peninsula had big influences on falling zone and intensity of cold airflow snowstorm.The snowstorm intensity obviously increased,and the snowfall center obviously moved northward.The main reason was that terrain caused the low-level wind field convergence and vertical movement in the troposphere strengthened.Then,the distribution of water vapor and snow water content in the space in the cold airflow snowstorm process obviously changed.So,the whole snowstorm process was affected.[Conclusion] The mountain terrain in Shandong Peninsula was the important element which needed to focus on considering in the forecast analysis of cold airflow snowstorm weather process.