Orographically Triggered Tropical Cyclones in the Eastern North Pacific

Zehnder博士将继续研究一种假设，即大多数东太平洋热带气旋的形成是由东风波与墨西哥和中美洲地形的相互作用造成的。在之前的一个奖项中，他完成了对吉列尔莫飓风的案例研究，该研究表明地形学在风暴的形成中发挥了重要作用。这项研究的下一阶段将包括对ECMWF网格数据（复合数据）、GOES数据的分析，以及MM5模式的模拟，以进一步记录地形强迫环流的存在及其在热带气旋形成中的作用。利用卫星数据来识别深层对流区域，Zehnder博士将根据ECMWF的数据集构建之前24-48小时内各种场的复合材料。他将寻找东风波的证据，并比较深层对流团发展成热带气旋和没有发展成热带气旋的情况。在建模部分，他将进行一些理想化的流动实验，以观察地形、东风波和北美季风槽的作用。

Dr. Zehnder will continue to investigate the hypothesis that most cases of Eastern Pacific tropical cyclogenesis results from the interaction between easterly waves and the orography of Mexico and Central America. Under a previous award, he completed a case study of Hurricane Guillermo which suggests that orography played a strong role in the formation of the storm. The next phase of this research will involve analysis of ECMWF gridded data (composites), GOES data, and simulations with the MM5 model to further document the existence of orographically forced circulations and their role in tropical cyclogenesis. Using satellite data to identify areas of deep convection, Dr. Zehnder will construct composites of various fields for the prior 24-48 hour period from the ECMWF data sets. He will look for evidence of easterly waves and compare those cases where deep convective clusters developed into tropical cyclones and those when they did not. For the modeling component, he will carry out a number of idealized flow experiments to look at the roles of orography, easterly waves, and the North American monsoon trough.