Effects of Island-induced Circulation on Localized Heavy Rainfall

9730072陈一段时间以来，人们就知道地形在暴雨的产生中起着重要的作用。地形引发的山洪是一个世界性的问题。1987年，美国与台湾联合开展了一项研究项目，旨在调查山区暴雨的动态。这项被称为台湾地区中尺度实验(TAMEX)的项目产生了大量数据，这些数据被用来了解环境和地形诱导的气流之间的相互作用及其对降水产生的影响。在这项研究中，首席调查员将继续分析TAMEX数据，同时使用先进的中尺度数值模式进行建模研究。具体目标包括：1)在锋前西南季风气流作用下，台湾西北沿岸障碍急流的结构和动力学；2)偏转气流和环境气流产生的中尺度辐合在西北沿海局地暴雨发生中的作用。此外，随着密集的地面和雨量网络已经到位，首席调查员将研究岛屿尺度气流的每日演变和岛屿上的降雨量分布。这项研究的成功完成将有助于更好地了解地形引发的山洪暴发的关键动力结构，并可能导致对这种危及生命的事件进行更好的预报。***

9730072 Chen It has been known for some time that orography plays a substantial role in the production of heavy rainfall. Orographic induced flash floods are a problem world- wide. In 1987, the U.S. in conjunction with Taiwan executed a research project aimed at investigating the dynamics of heavy rainfall in mountainous terrain. This project, known as the Taiwan Area Mesoscale Experiment (TAMEX) produced a wealth of data which is being used to understand the interactions between environmental and orographic induced flows and their impact on precipitation production. In this study, the Principal Investigator will continue analysis of TAMEX data in conjunction with modeling studies using an advanced mesoscale numerical model. Specific objectives include to investigate 1) the structure and dynamics of the barrier jet along the northwestern coast of Taiwan under the pre-frontal southwesterly monsoon flow; 2) the role of mesoscale convergence generated by the deflected airflow and environmental flow on the occurrences of localized heavy rainfall along the northwestern coast. In addition, with the dense surface and rain gauge networks that are already in place, the Principal Investigator will study the diurnal evolution of island-scale airflow and rainfall distributions over the island. Successful completion of this research should lead to a better understanding of critical dynamical structures of orographic induced flash floods and may lead to better forecasts of such life-threatening events. ***