Conditions Favorable for the Development of Heavy Precipitation During TAMEX

山洪暴发是全球范围内发生的重大气象灾害。理解这一现象是一个具有挑战性的问题，因为有必要理解运动尺度上的复杂动态和微物理过程，这些运动尺度比传统气象网络通常测量的要小。这种运动尺度被气象学家称为风暴尺度或中尺度。台湾国家科学委员会建立了一个多重灾害缓解项目，其气象部分的重点是改善山洪暴发的预测。1987年春，台湾地区中尺度实验(TAMEX)举行了一次重要的实地考察项目。该项目是台湾多个机构的共同努力，国家海洋和大气管理局和国家科学基金会(NSF)都参与了该项目。科学目标是研究中尺度系统，这些系统形成在被称为梅雨锋的准静止和一致的特征上，并导致被称为“梅雨”的暴雨。在之前的一次奖励中，首席调查员使用在TAMEX期间收集的特殊观测数据进行诊断研究，以确定暴雨形成的重要因素。这些研究使首席调查员专注于三个主题--低空急流的动力学；盛行的西南风下在台湾西北向风海岸形成的障碍急流；以及高层环流。除了利用观测数据进行进一步分析外，首席调查员还将利用数值模式帮助确定暴雨产生的重要动力因素。

Flash floods are major meteorological disasters which occur around the globe. Understanding of this phenomenon is a challenging problem because it is necessary to understand both complex dynamic and microphysical processes at scales of motion that are smaller than typically measured by conventional weather networks. This scale of motion is termed storm-scale or mesoscale by meteorologists. The National Science Council of Taiwan established a Multiple Hazards Mitigation Project whose meteorological component focused on improving flash flood predictions. A major field project, entitled the Taiwan Area Mesoscale Experiement (TAMEX), was held in the Spring of 1987. The project was a joint effort of various Taiwanese agencies with participation from the National Oceanic and Atmospheric Administration and the National Science Foundation (NSF). The scientific goals were to study the mesoscale systems that form on a quasi-stationary and consistent feature known as the Mei-Yu front and cause the heavy rains known as the "plum rains". Under a previous award, the Principal Investigator used the special observations collected during the TAMEX in diagnostic studies that identified important factors for the formation of heavy rainfall. These studies have lead the Principal Investigator to concentrate on three topics -- the dynamics of the low level jet; the barrier jet which forms along the northwest windward coast of Taiwan under the prevailing southwesterlies; and the upper-level circulations. In addition to further analysis using the observational data, the Principal Investigator will utilize a numerical model to help identify the important dynamic factors for heavy rain production.