陇南市一次重危害霜冻天气过程分析

Analysis of a Heavy Damage Frost Weather Process in Longnan City

通过分析2013年4月5～6日陇南市发生的一次重危害霜冻天气过程,总结了此次霜冻过程形成的主要原因,并针对此次霜冻天气订正了原有的霜冻天气预报指标,尝试寻找新的预报着眼点。结果表明,前期温度异常偏高状态为此次强降温霜冻天气的发生积累了能量;咸海里海暖高压中心的形成为新地岛附近冷空气的南下以及原有低槽冷空气的增强提供了有利条件;此次过程前期的降水天气不利于霜冻的形成,但由于冷空气强,加上降水过后天气转晴,辐射降温加强,强霜冻是平流降温与辐射降温综合影响的结果。欧洲中心数值预报形势场的预报对此次霜冻天气的预报有很好的指示作用。

Through analyzing a heavy damage frost weather process in Longnan City during Apr. 5 -6, 2013, the main causes were summarized. Aiming at the frost weather, the original frost weather forecasting indicators were revised, so as to find a new forecasting point. The results showed that the abnormal higher temperature accumulate energy for the frost weather; The formation of Caspian Sea warm high pressure center provides favorable conditions for southward of cold air around Xindi Island and enhancement of original low trough cold air; The strong forest is the result affected by advection cooling and radiation cooling. Forecasting of ECMWF situation field has a good indicating effect on the frost weather prediction.