2010年京、津、冀一次降雪天气的诊断分析

Diagnostic Analysis of a Snowfall Weather in Beijing,Tianjin and Hebei in 2010

[目的]分析2010年1月1～4日发生在京、津、冀地区的一次局地暴雪天气过程。[方法]利用常规气象观测数据和NCEP/NCAR每日4次的2.5°×2.5°的格点资料,采用合成分析方法,对2010年1月1～4日发生在京、津、冀地区的一次局地暴雪天气过程进行诊断分析。[结果]地面高压底部暖湿气流与高空槽后强冷平流的共同作用是造成这次降雪的主要天气系统;深厚的湿层与强烈的水汽辐合为降雪提供了充沛的水汽;低层辐合、高层辐散的散度场以及涡度的动力耦合作用为强降雪的出现提供了有利的动力上升运动条件;近地面层θse陡峭密集区、低温以及高层逆温的存在为降雪天气的发生发展提供了一定的能量条件。[结论]该研究为今后的降雪预报提供理论依据。

[Objective] The research aimed to analyze a local snowstorm weather process which happened in Beijing,Tianjin and Hebei during 1-4 January,2010.[Method] Based on the routine meteorological observation data and NCEP/NCAR 2.5°×2.5° grid data（four times in every day）,a local snowstorm weather process which happened in Beijing,Tianjin and Hebei during 1-4 January,2010 was carried out diagnostic analysis by using composite analysis method.[Result] The common effect of warm wet airflow at the bottom of ground high pressure and strong cold advection in the rear of high-altitude trough was the main weather system of the snowfall.The deep thick wet layer and strong water vapor convergence provided sufficient water vapor for snowfall.The dynamic coupling effect of divergence field（convergence at low layer and divergence at high layer） and vorticity provided the favorable dynamic ascending movement condition for the occurrence of strong snowfall.The steep intensive area of near surface layer,low temperature and temperature inversion at high layer provided the certain energy condition for the occurrence and development of snowfall weather.[Conclusion] The research provided theoretical basis for snowfall forecast in future.