Tropical Cyclogenesis in the Northwest Pacific

弗兰克博士将对导致西太平洋热带气旋发展的过程进行调查。这项研究结合了观测分析和数值模拟实验，将重点放在气旋发生的最早阶段。偶尔，在组织松散的热带云团内会形成一个强烈的中尺度涡旋。多年来，研究人员已经相当清楚地描绘了导致其中一些涡旋成长为成熟热带气旋的过程(飓风/台风生命周期的“强化”阶段)。相比之下，人们对“创世”阶段知之甚少。弗兰克博士将研究热带气旋发生期间出现的大尺度环流模式，这些模式的起源，以及导致涡旋形成的物理过程。天气尺度的西南气流涌入西太平洋季风槽经常被观测到在该地区气旋生成之前。将特别注意它们在环流发生中的作用。观测分析将基于五年的全球数据集，以及弗兰克参加的1990年热带气旋运动实验期间收集的高分辨率数据集。模拟研究将使用新开发的PSU/NCAR中尺度模式的非静力版本来模拟西太平洋典型各种条件下的涡旋形成。这项研究对于理解并最终预测热带气旋的发展将是重要的。

Dr. Frank will conduct an investigation of the processes that lead to tropical cyclone development in the western Pacific. The study, which combines observational analyses and numerical modeling experiments, will focus on the earliest stages of cyclogenesis. Occasionally, a strong mesoscale vortex forms within a loosely organized tropical cloud cluster. Over the years, researchers have developed a fairly clear picture of the processes which cause some of these vortices to grow into mature tropical cyclones (the "intensification" phase of the hurricane/typhoon life cycle). By comparison, the "genesis" phase is very poorly understood. Dr. Frank will examine the large scale circulation patterns present during tropical cyclogenesis, the origins of these patterns, and the physical processes leading to vortex formation. Synoptic-scale surges of southwesterly flow into the West Pacific Monsoon Trough are frequently observed to precede cyclogenesis in this region. Particular attention will be given to their role in cyclogenesis. The observational analyses will be based on a five year global data set, and on high resolution data sets collected during the Tropical Cyclone Motion experiment of 1990, in which Frank participated. The modeling studies will employ the newly developed nonhydrostatic version of the PSU/NCAR mesoscale model to simulate vortex formation under a variety of conditions typical of the West Pacific. This research will be important for understanding, and ultimately predicting, the development of tropical cyclones.