Large-Scale Influences on Tropical Cyclogenesis

本项目将研究“热带气旋的归属”，以确定每个热带气旋在一个季节中发展出来的主要预先存在的扰动(S)。研究人员将(1)开发和应用一种将热带气旋发生归因于一种或多种赤道波的方法；(2)处理关于热带气旋前兆文献中现有论文的巨大分歧；(3)尝试将传统的热带气象学做法与利用赤道波理论的替代框架相结合。最后一部分工作的目标是将一些想法从研究界转移到热带气旋预报业务界。研究人员在之前的NSF支持中研究了混合Rossby重力、赤道Rossby、东风波和Madden-Julian振荡在热带气旋发生中的作用。在这个项目中，他们将研究“季风环流”中热带气旋的形成。这些都是广袤的副热带低压地区，经常会产生多个热带气旋。这两部分工作的最终目标是制定一种统一的方法来理解热带气旋的前兆扰动。该项目的更广泛影响包括：(1)将依赖卫星图像的业务预报方法与一些更好地界定前兆扰动的新理论办法结合起来，最终改进5-10天时间尺度上的飓风形成预报；(2)对研究生进行培训；(3)在会议、讲习班和参考文献中广泛传播结果和结论。作为外联工作的一部分，首席调查员还将向非专业团体发表关于飓风的演讲。

This project will examine "tropical cyclone attribution" to identify the primary pre-existing disturbance(s) out of which each tropical cyclone in a season develops. The investigators will (i) develop and apply a means of attributing tropical cyclogenesis to one or more types of equatorial waves; (ii) address the wildly divergent views of existing papers in the literature on tropical cyclone pre-cursors; and (iii) attempt to merge traditional tropical meteorology practice with an alternative framework that makes use of equatorial wave theory. The goal of the last part of the work is to move some ideas from the research community into the operational tropical cyclone forecast community.The investigators have examined the role of mixed Rossby-gravity, equatorial Rossby, easterly waves and the Madden-Julian Oscillation on tropical cyclogenesis in their previous NSF support. In this project they will study tropical cyclone formation within "monsoon gyres". These are broad subtropical low pressure areas that often produce multiple tropical cyclones. The ultimate goal of the two parts of this work is to develop a unified approach to understanding the precursor disturbances for tropical cyclones. The broader impacts of this project include (i) the potential in merging operational forecast methods that rely on satellite images with some new theoretical approaches that better define the precursor disturbances, to ultimately improve the forecasts of hurricane formation on a time scale of 5-10 days, (ii) the training of graduate students and (iii) wide dissemination of results and findings in conferences, workshops, and the refereed literature. The principal investigator will also give talks on hurricanes to lay groups as part of outreach efforts.