Tropical cyclones (TCs) are not only some of the most destructive storms on the planet, but also fascinating to study. However, the dynamics of TCs–including their genesis and intensification–are challenging to fully understand for a variety of reasons including the complex multi-scale interactions between small-scale convection and the large-scale forcing, as well as the coupled ocean-atmosphere processes at work, and the difficulty in obtaining observation over the vast ocean where they spend the majority of their lifetime. These challenges make TC dynamics an exciting and rich research field. My research to date has sought to improve our understanding of TC intensification.

One example comes from recent work examining the record-breaking intensification of Hurricane Patricia (2015). Using high-resolution (1-km horizontal grid spacing) WRF ensemble forecasts, initialized from the EnKF analysis of a cycling ensemble data assimilation system, I found the vortex breadth and radial structure especially important in simulating a Patricia-like intensification. Despite ensemble members having initially similar maximum wind speeds, ensemble members with a broader vortex beyond the RMW were found to intensify the greatest, which we hypothesize to be the case primarily because ensemble members with greater angular momentum beyond the RMW can radially advect this angular momentum inward, thus strengthening the storm through conservation of angular momentum. It is also possible that a broader initial vortex may be more resilient to detrimental environmental conditions (e.g. dry air or vertical wind shear), although the environmental conditions were generally favorable for intensification in the case of Patricia.

I am also working to better understand the air-sea interactions associated with tropical cyclones, which have been previously shown to significantly modulate the development, structure and intensification of tropical cyclones. I am specifically interested in the uncertainties in the representation and parameterization of the air-sea fluxes of enthalpy and momentum that currently exist, at least in part, because of the difficulty in obtaining observations of the air-sea fluxes at high wind speeds. I have found, using the current uncertainty estimates of the physics of the air-sea fluxes, manifested through altering the enthalpy and momentum exchange coefficients in the air-sea flux parameterization scheme, that the intensity forecast uncertainty resulting from only the uncertainty related to the air-sea fluxes is comparable to that from initial condition uncertainty, suggesting realistic physics uncertainty associated with the representation and parameterization of air-sea fluxes can be a significant source of uncertainty limiting the current predictability of intense TCs. I hope by better understanding the dynamics associated with the air-sea fluxes to reduce the associated physics uncertainty, ultimately improving the predictability of TCs.