Simulating the Structure of Hurricane Katrina

Hurricane Katrina underwent an asymmetric transition near landfall and has a double eyewall. While the asymmetries could largely be attributed to the vertical shear and fast movement, previous studies have also revealed the time-varying nature of the convective activities over the right portion of the eyewall at landfall. In this study we attempt to simulate these features with the WRF-ARW model.

Preliminary results with high temporal resolution (1 min.) output verified the fast-varying characteristics of rainfall. The relationship between the simulated rainfall and the surface wind and turbulent kinetic energy are being investigated. Their validity are checked against available observations.

The evolution of the double eyewall will also be simulated by initialization with radiance/radar observations and bogus vortex observations that permit two wind maxima, and the influence on the intensity and structure changes will be studied.