2008年初低温雨雪天气特征分析

2008年1月中旬～2月初,湖北荆州市经历了一次历史罕见的持续低温降雪天气过程,通过对这次的低温雨雪过程的天气特征、物理量场和多普勒雷达回波分析,期望为今后的预报中对降雪预报提供一定参考。分析表明,旺盛的西南急流,强的垂直风切变,高层辐散与低层辐合的配置,提供了降雪区的上升运动与水汽的辐合;强冷空气维持,逆温层结构决定了降水的性质,而中高纬度稳定的阻塞形势和中低纬度平直环流和南支多波动,使雨雪天气持续。

Weather Characteristics Analysis on the Cryogenic Freezing Rain and Snow Weather in the Beginning of 2008

A cryogenic freezing rain and snow weather,which was seldom seen in history occurred in Hubei Jingzhou. Through analysis of the weather characteristics and the physical quantity and the radar echo of DOP on the cryogenic freezing rain and snow weather,some reference to the forecast of snow were provided. The paper found that what provided a very favorable condition for the increased movement and the convergence with water vapor in the fall area were the southwesterly jet and strong wind shear vertically and a divergence and lower convergence; the long-existing cold air and the inversion layer decided the state of precipitation,while the main reason of the long-time freezing rain and snow weather was the blocking at high latitude and active fluctuation in south flows.