Studies on the extra-tropical transition of typhoons and accompanied meteorological hazards due to meso-scale disturbances

台风起源于西太平洋。其中几个向北迁徙，在日本群岛造成了各种危险。台风北移时，会与中纬度斜压环境相互作用，改变台风结构。这种变形过程被称为温带过渡。在温带过渡的过程中，各种中尺度系统的发展是造成气象灾害的主要原因。对于在近木地区特别是奈良拜辛造成严重风害的T9807(Vicki)，利用从消防站(128个站)收集的地面气象资料，仔细研究了其表面结构。在大部分站点，最大风速出现在台风中心在其后侧通过后。与资料回波的对比表明，大风事件发生在台风中心后方形成的雨带附近。用PSU NCAR MM5中尺度气象模式对该个例进行了数值模拟，再现了雨带的形成和伴随的大风。对造成日本西部风暴袭击和日本中部太平洋沿岸龙卷风天气的T9918(BART)进行了不同分辨率的数值模拟。在精细网格模拟的基础上，对台风环流中的热带风暴和环流环境进行了仔细的分析。通过区域尺度模拟再现了台风的整个历史过程，包括其显著的再加强过程，并利用模拟结果对热带外转换过程中的动力学进行了诊断。秋季台风有时会伴随中尺度扰动，称为气压下降，即台风环流。研究了这种扰动的气候学特征和结构。并用MM5进行了仿真，分析了该扰动的具体结构和产生原因。

Typhoons originated in the western pacific ocean. Several of them migrate to the north and cause various hazard in Japanese Islands.. When a typhoon migrates to the north, it interact with the mid-latitudes baroclinic environments and change it structure. This deformation process is called extratropical transition. In the cource of extratropical transition various meso-scale systems developes, which act as a major cause of meteorological hazard.As for T9807(Vicki) which caused serious wind damages in the Kinki district, especially in the Nara Baisin, its surface structure was closely investigated using surface meteorological data collected from fire stations(128 stations). At the most of stations, the highest wind took place after the passage of the typhoon center at its rear side. A comparison with data echoes shows that high wind events took place around a rain band formed to the rear of the typhoon center. This case was also simulated with a Meso-scale Meteorological Model, PSU NCAR MM5, and the formation of the rain band and the associated strong wind were reproduced by the model simulation.For T9918(Bart) which caused storm serege at the western Japan and also caused tornadic storm at the Pacific coast of central Japan, a suit of numerical simulation was conducted in var4ious resolution. The tronadic storm and the environment in the typhoon circulation were closely examined based on the fine mesh simulation. The entire history of the typhoon including its remarkable reontensification were reproduced by regional scale simulations and the dynamics in the process of extra-tropical transition is dignosed using the simulated results.Autumn typhoons sometimes accompany meso-β scale disturbance, termed as the pressure dip, the typhoon circulation. The climatological features and the structure of this disturbance were examined. This was also simulated by the MM5 and the detailed structure and the cause of this disturbance were analyzed.