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。其中一些向北迁移，在日本群岛造成各种危害。当台风向北迁移时，它与中纬度斜压环境相互作用并改变其结构。这种变形过程被称为温带过渡。在温带过渡过程中，各种中尺度系统的发展是造成气象灾害的主要原因。对于在近基地区特别是奈良白信地区造成严重风害的T9807(Vicki)，利用128个消防站的地面气象资料对其地表结构进行了严密的调查。在大多数台站，最大的风发生在台风中心通过后的背面。与回波数据的比较表明，大风事件发生在台风中心后方形成的雨带周围。利用PSU NCAR MM5中尺度气象模式模拟了此次暴雨过程，模拟结果再现了暴雨带的形成过程和强风的形成过程。对引起日本西部风暴的T9918(Bart)，在日本中部太平洋沿岸也引起了龙卷风风暴，进行了一套不同分辨率的数值模拟。在细网格模拟的基础上，对台风环流中的对流层风暴和环境进行了细致的研究。通过区域尺度模拟再现了台风的整个历史，包括其显著的再强化，并利用模拟结果诊断了热带外过渡过程中的动力学。秋季台风有时伴有中β尺度扰动，称为气压下降，台风环流。研究了该扰动的气候特征和结构。用MM5模拟了这种扰动，分析了扰动的详细结构和产生原因。

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.