台风活动对陕西重大洪灾事件影响的综合分析

A Comprehensive Analysis of Typhoon Influences on Major Flooding Events in Shaanxi

运用统计学、天气学、卫星云图和物理诊断等方法,对1970—2004年35年间发生在陕西重大洪灾事件和近海台风活动(130°E以西的台风)进行分析。结果发现,陕西重大洪灾与近海台风活动相关率达90%。重大洪灾事件主要集中在7、8两个月,约占88%,当影响台风在南海区域生成或从西太平洋西移穿越过130°E时,对陕西重大洪灾影响明显。其暴雨的水汽、能量主要依靠台风低压外围的偏东风急流来输送,以850 hPa层输送最为显著。近海台风活动为引发陕西重大洪灾的暴雨发生、加强,提供了必需的能量和水汽条件,台风的作用是造成陕西重大洪灾事件相当重要的因素。

The offing typhoon in west of 130°E and major flooding events in Shaanxi during the past 35 years（1970-2004） were analytically studied by applying methods of statistics,synoptic,satellite cloud image analysis and physical diagnosis.Results show that the correlation is close to 90%.Major flooding events are concentrated in July and August,occupying nearly 88%of the total.When a typhoon originates in 130°E or moves westwards from the West Pacific across 130°E,it has more obvious influences on major flooding events in Shaanxi.The required water vapor and energy are transited through easterly winds around the typhoon center,especially in 850 hPa level.The offing typhoon provides necessary water vapor and energy to the occurrence and enhancement of flood-causing torrential rain in Shaanxi,and typhoon influence is an important factor to induce major flooding events in Shaanxi.