地形对0604号"碧利斯"登陆台风暴雨的影响

利用NCEP再分析日资料和常规观测资料等,对2006年第4号强热带风暴"碧利斯"登陆后造成内陆暴雨特别是湘东南特大暴雨的成因进行了分析。结果表明,华南大范围暴雨带与低气压南部的一条切变—槽以及从低压西侧卷入的干、湿两股气流间形成的"湿度锋区"有关;而独立存在于湘东南的尺度较小而强度特大的一条NNE—SSW向的暴雨带则与罗宵山脉的地形影响有密切关系,地形强迫上升及其对暴雨的触发主要不在山坡上,而是在迎风坡气流上游平原地区(即湘东南),实况与理论估算和推断结果一致。由于气流在湘东南平地辐合上升,它的触发作用成为湘东南特大暴雨发生的重要原因。

The Effect of Terrain on Landing Typhoon 0604 Bilis

Used NCEP reanalysis data and observations,the causes of rainstorm occured in inland area,particular in the southeast of Hunan by the landing Typhoon 0604 Bilis was analysed.The results shows that,in the circulation condition of landing Tropical Cyclone,the heavy rain in South China is related to the shear-trough at the south side of the cyclonic circulation and the "moisture frontal zone" between a dry stream and a wet stream immixtured from the west of low press area.But the heavy rain in the southeast of Hunan is immediately related to the terrain of Luoxiaoshan mountain range.The terrain-forced ascending motion and its triggering heavy rain don't occurred on the hillside but the plain,which is the upstream zone of the airflow over the windward mountain slope.This fact can be well explained with Pierrhumbert's theorem.