Collaborative Research: EAGER--Tropical Cyclone Vortex Characteristics Identified by Liutex

The eyewall in mature hurricanes contains small vortices, which have been seen in satellite and weather radar data. While the presence of these vortices is well-known, their impact on the hurricane structure and intensity is still uncertain. In this award, the research team will use a recently derived mathematical framework to analyze hurricane vortices with a goal of better explaining how the small-scale vortices relate to the large-scale hurricane structure. The primary societal benefit of this project would be through the potential for improved forecasting of hurricanes. A graduate student and postdoctoral researcher would be involved in the project, allowing for the training of the next generation of scientists. Liutex is a recent methodological advancement in the field of mathematics and fluid dynamics that intends to better represent vortices in fluids, like the atmosphere. Liutex is a vector whose direction is aligned with the rotational axis and whose magnitude is twice the angular speed. It separates the pure rigid rotation from shear. Small-scale vortices within hurricanes provide a strong test case for Liutex. The research team plans to apply Liutex to observations and numerical modeling of three-dimensional winds in hurricanes to quantify the relationship between vortex structure and storm intensity and to identify mechanisms of vortex formation and mergers. The overarching goal of the project is to gain a deeper understanding both theoretically and numerically of how the eye-eyewall meso- and miso- vortices form and provide a sound method to identify them and quantify their structures. 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.