鹰潭市一次冻雨暴雪天气过程分析

利用常规气象资料、T213资料等，对鹰潭市2008年2月1-2日出现的冻雨、暴雪天气过程进行分析。结果表明，暴雪出现在500hPa槽前、700hPa急流轴与切变线之间、850hPa切变线附近和地面冷高压底部的区域。高空低槽东移，700hPa西南急流的南压，使得700hPa温度下降为-3．7℃，温度条件变化有利于产生降雪。中低层辐合、高层辐散及较强的上升运动，为强降雪提供较好的动力条件。850—700hPa的逆温层有利于冻雨、暴雪出现，当700hPa温度≥-1℃时，出现冻雨；当温度≤-3℃时，出现暴雪。对流层中层较好的水汽输送，是暴雪发生的重要原因之一。

A Freezing Rain and Heavy Snow Case in Yingtan City

In this paper, the conventional meteorological data and T213 data were employed to analyze the freezing rain and heavy snow case happened in February 1-2, 2008 in Yingtan city. The results indicated that the heavy snow occurred in front of 500 hPa trough, between the 700 hPa axe of jet stream and the shear line, and in the area between 850 hPa shear line and the bottom of surface cold high. The upper trough moving eastward and the 700 hPa southwesterly jet moving southward caused 700 hPa temperature dropping to -3.7 ℃, which was the favorite temperature condition for snowfall. The low-to-middle level convergence, the high-level divergence and the strong ascending motion provided preferable dynamic conditions for snow. The 850-700 hPa inversion layer was advantageous to the freezing rain or heavy snow occurrence. If the 700 hPa temperature ≥-1 ℃, freezing rain might occur, or if the 700 hPa temperature ≤-3℃, heavy snow might happen. Sufficient water vapor transport at the middle troposphere was one of the important conditions for heavy snow occurrence.