摘要:2016年9月14~15日超强台风“莫兰蒂”（1614）登陆厦门后在福建省中北部引发了特大暴雨天气过程，特大暴雨由台风登陆后北侧至东北侧一个缓慢移动的长生命史中尺度强对流螺旋雨带活动造成。利用中尺度数值模式WRF（V3.9）对台风登陆引发福建省中北部特大暴雨过程进行了大区域无嵌套数值模拟，较准确地模拟了台风引发特大暴雨的强度和落区，并成功地再现了台风登陆后北侧至东北侧长生命史中尺度强对流螺旋雨带的发生、发展过程。分析发现，台风大风区外围几个零散的中尺度辐合区在移入台湾地形下游的弱风切变区、正涡度带、湿静力能（假相当位温、比湿）锋区后，组织发展成一个带状的中尺度辐合带而形成强对流螺旋雨带，长时间地维持和发展，并向东北方向缓慢移动。台湾地形在有利于强对流螺旋雨带长时间组织发展和维持的中尺度环境场的形成中扮演着重要角色，即地形效应在其下游形成的正涡度带（正位涡带）、雨带（位于高湿静力能区）南侧低湿静力能带（即湿静力能锋区），对强对流螺旋雨带的长时间发展维持非常重要。地形敏感性试验的结果进一步证实了台湾地形在台风登陆后东北侧长生命史中尺度强对流螺旋雨带形成及维持中的重要作用。
关键词:台风/
特大暴雨/
中尺度地形/
数值模拟
Abstract:The super typhoon "Meranti" (1614) landed at Xiamen City and produced extremely heavy rain in the central-northern Fujian Province during 14-15 September 2016. A slow-moving long-lasting intensive convective spiral rain-band in the northern and northeastern parts of the typhoon circulation led to the extremely heavy rain after the typhoon made its landfall. A large-domain numerical modelling without nesting was carried out to simulate the extremely heavy rain produced by the landfalling typhoon "Meranti" using mesoscale numerical model WRF (V3.9). The model accurately simulated the intensity and location of the extremely heavy rain, and successfully reproduced the formation and development of the long-lasting intensive convective spiral rain-band after the typhoon made landfall. Analysis of the results indicates that several scattered mesoscale convergences were organized into a mesoscale convergence band and triggered the intensive convective spiral rain band, which maintained and developed for a long time and moved northeastward slowly after they moved into the area of weak-wind shear, positive vorticity band and moist static energy (pseudo equivalent potential temperature, specific humidity) front in the downstream of the Taiwan topography. The Taiwan topography plays a very important role in the formation of the mesoscale environment favorable for the long-time maintenance and development of the mesoscale intensive convective spiral rain-band. The topographic effect is helpful for the formation of a positive vorticity band (positive potential vorticity band) and a low moist static energy area to the south of the rain band (that is, a moist static energy front) in the downstream of the Taiwan topography, which is very important for the long-time maintenance and development of the mesoscale intensive convective spiral rain-band. The results of topographic sensitivity experiment further verify the important role of the Taiwan topography in the formation and maintenance of the long-lasting intensive convective spiral rain-band in the northeastern part of the typhoon circulation after the typhoon made landfall.
Key words:Typhoon/
Extremely heavy rain/
Mesoscale topography/
Numerical simulation
PDF全文下载地址:
http://www.iapjournals.ac.cn/dqkx/article/exportPdf?id=20190103
