65th IHC Booklet/Program (pdf - 4.9MB) - Office of the Federal ...

Controlling Factors of the Radius of Maximum Winds in HWRF
Jian-Wen Bao, Sara A. Michelson, Sundararaman G. Gopalakrishnan
(Jian-Wen.Bao@noaa.gov)
NOAA/ESRL and NOAA/AMOL
This presentation highlights major results from a series of numerical experiments with
NOAA’s Hurricane WRF (HWRF) model. The purpose of the experiments is to investigate the
sensitivity of the radius of maximum winds of an idealized tropical storm to the model’s internal
controlling factors (such as the size of the initial vortex, cloud physics and vertical diffusion) and
external conditions (such as the latitude-dependent Coriolis parameter). The model is initialized
with a weak axisymmetric vortex disturbance in an idealized tropical environment that is
favorable for the vortex disturbance to develop into a hurricane. The initial mass and wind fields
associated with the weak vortex disturbance are obtained by solving the nonlinear balance
equation for the given wind distributions of the initial vortex, and the prescribed background
thermal sounding and winds. Results from the idealized HWRF sensitivity runs are compared in
terms of the radius of maximum winds along with the azimuthally averaged storm structure and
the surface wind-pressure relationships, to gain an insight into how to improve the model.
Session 7 – Page 6