“04．12．21”飞机积冰天气过程数值特征分析

Analysis of an Aircraft-icing Event in Taiyuan Airport

通过对2004年12月21日发生在民航太原机场附近的飞机积冰过程分析认为: 华北地面高压和河套地区高空槽形成的“回流+倒槽”形势是此次积冰的天气背景, 在具备暖湿环境的条件下,在冷暖空气交汇区域靠近冷空气一侧易发生积冰;除去飞机动力增温影响后,强积冰所需环境温度大致在-6--10℃之间;弱上升气流和冷平流已经侵入的区域内有利于积冰的形成;WAFS数值预报产品可较有效地描述天气系统发展的动力结构和机制,具有较好的积冰形势预报能力,而在国际民航组织向成员国推荐的积冰指数基础上重新构造的积冰指数可以更好地预报积冰天气的发生区域。

An analysis of the case of aircraft-icing occurred in Taiyuan airport of Shanxi Province 21 December, 2004 is made. It shows that the upper-trough in Hetao area and the high-pressure over the North China composed the background of this event. The equivalent temperature of environment lied between -6℃ and -10℃ was necessary for severe icing when the environment had plenty of moisture. The weak ascend velocity and cold advection are favourable to ice accumulation, WAFS NWP products can effectively describe the dynamics structure of synoptic system. A new icing index can better predict the icing event than the recommended icing-index by ICAO.