登陆台风云系中列车效应回波带形成机制研究

Landing typhoon in China is a very important factor that cause great loss of life and property in coastal area. Typhoon rainstorm is closely related to spiral rainbands. And in typhoon's rainbands, heavy rainstorm is commonly related to convective cells that move in line. In other words, strong narrow linear radar echoes usually exist in typhoon spiral rainbands. Sometimes radar echoes' motion is tangential to typhoon's spiral flow. When convective cells move continuously, the radar echoes appear to be a band, thus becoming “echo training” and causing great damage. Therefore, this project will use conventional and unconventional data, assimilation scheme, and high resolution mesoscale simulation result to analyze linear radar echoes in spiral rainbands of landing typhoon in Zhejiang and Fujian, as well as its formation mechanism and evolution process. Based on this, we are going to make further research about the relationship between mesoscale heavy rainstorm and mesoscale circulation of linear radar echoes in typhoon spiral rainbands. We will also study rainstorm's schematic model of mesoscale system in which typhoon's linear echoes exist.

我国登陆台风是严重影响沿海地区经济、生命和财产损失等的重要因素。观测发现台风暴雨与螺旋云带密切相关，而强暴雨灾害又常与台风螺旋云带的对流单体带状偏离台风中心运动有关，即台风螺旋云带常存在呈强、狭、长带状雷达回波，该强回波带有时与台风螺旋环绕气流呈短时切向运动，并随对流单体连续运动而成呈现带状走向，由此造成暴雨对流单体的“列车效应”而产生重大灾害。因此，本项目研究将利用台风强暴雨的常规和非常规资料及同化方案，利用较好的中尺度数值模拟高分辨结果，分析研究我国东部登陆台风螺旋云系中的线状回波带，以及线状回波带发生发展形成机理与演变过程。在此基础上进一步分析探讨登陆台风螺旋雨带中的线状回波带的中尺度强暴雨与中尺度环流之间的关系和预报信息。研究台风线状回波这一类型所发生的强暴雨带中尺度系统发展的概念模型。