Characteristics of Boundary Layer Structure and Evolution of a Landfalling Hurricane with High-Resolution Numerical Simulations

This study aims for a better understanding of the evolution of hurricane structure and its interaction with the atmospheric boundary layer during its landfall. Our research objectives include 1) examining the influence of the atmospheric boundary layer (environmental) conditions on the intensity and structure of landfalling hurricanes, 2) to determine how the hurricane vortex and secondary circulations interact with the atmospheric boundary layer environmental conditions. In order to achieve the objectives, a high-resolution numerical simulation was conducted for Hurricane Katrina (2005) to simulate part of its life cycle before and during its landfall in Louisiana using an advanced research version of the Weather Research and Forecasting (WRF) model. The model simulations are validated by observations made from the NASA TRMM satellite data, radar, and dropsondes observations collected by the NOAA Hurricane Research Division (HRD) operational/research flights. Results show that the simulation has captured the main features of Hurricane Katrina based off the comparisons made with the radar observations, precipitation measurements, HRD wind analysis, and NHC best track data. The numerical simulation data is also used to diagnose the characteristics of Hurricane Katrina's evolution, intensity and structural changes, and its interaction with environmental boundary layer conditions during its landfall. The implications of the numerical results for the mechanisms that control the evolution of landfalling hurricanes are also further investigated.layer conditions during its landfall. The implications of the numerical results for the mechanisms that control the evolution of landfalling hurricanes are also further investigated.