Environmental controls over tropical cyclone formation

Tropical cyclones (TCs, also known as hurricanes in the North Atlantic basin) are among the major extreme weather events that pose a high risk to the economy and society every year. Despite great progress in studying TC development over the last several decades, our current understanding of TC processes is still inadequate. A direct consequence of this lack of understanding of TC formation is our limited capability in predicting TC formation in practice. Thus, improving the understanding of TC formation processes and TC subsequent development is of significance for both the advance of science and social safety and risk management. Using numerical simulations along with recent machine learning techniques, this project introduces a new approach to TC research that can help unfold the dominant mechanisms underlying TC formation in different ocean basins. Unlike the traditional vortex tracking methods in the current TC research and operation, the approach in this project offers an alternative way to search for new environmental factors governing TC formation. By exploring the practicality of these machine learning methods for TC research, this project will not only introduce an innovative way of studying tropical cyclogenesis but also help train a new generation of workforce in the area of artificial intelligence applications for atmospheric research. This project combines several new modelling and machine learning methods to investigate two key scientific questions: 1) what are the key environmental factors that control different TC formation pathways in different ocean basins, and 2) whether global tropical cyclogenesis possesses an episodic development, and if so, what environmental factors determine the frequency of this global TC formation. Using a combination of model simulations, physical diagnostic analyses, and machine learning algorithms, this project will look into major environmental conditions and their dynamical constraints in the tropical atmosphere that are insufficiently represented in the current TC genesis potential index framework. These environmental constraints will help determine different favorable conditions for TC formation and how to use these factors for studying the shift of TC climatology in the past and future climates. The outcomes from this project will also bring more insights into the physical mechanisms behind the maximum capacity of the tropical atmosphere in generating TCs annually in our current Earth’s atmosphere. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.