Large-Scale Influences on Tropical Cyclogenesis

这个项目涉及大尺度大气流动的三个方面对热带气旋形成的影响的研究。以往的观测研究表明，与对流层上层反气旋外流相关的负涡度异常与环境正涡度异常之间的相互作用与这些异常的强度有关。一个浅水模式将用于进行数值实验，以试图更好地了解这些相互作用在随后的热带气旋发展中的性质。该项目的第二部分涉及对垂直风切变方向在热带气旋发展中的作用的观测研究，特别是相对于高层涡度的相反影响。这将使用ECMWF网格分析来完成。第三部分将通过分析ECMWF网格场和数值模拟工作，考察时间平均位涡场在大西洋和东太平洋热带气旋的形成和运动中的作用。＊＊＊

9529771 Molinari This project involves the study of the influence of three aspects of large-scale atmospheric flow on tropical cyclogenesis. Previous observational studies have suggested that interactions between the negative vorticity anomalies associated with upper tropospheric outflow from anticyclones and environmental positive vorticity anomalies are related to the strength of those anomalies. A shallow water model will be used to conduct numerical experiments to try to better understand the nature of these interactions in subsequent tropical cyclone development. The second part of the project involves an observational study of the role the direction of vertical wind shear in tropical cyclone development, particularly relative to the opposing influence of upper level vorticity. This will be accomplished using ECMWF gridded analyses. The third part will consist of an examination of the role of the time-averaged potential vorticity field on the genesis and movement of tropical cyclones in the Atlantic and eastern Pacific through analysis of the ECMWF gridded fields and numerical modeling work. ***