SEMINAR: CIMAS Visiting Scientist - Prof. Da-Lin Zhang - Friday, March 26 - 2:00PM - SA103

[mloi@rsmas.miami.edu]

CIMAS VISITING SCIENTIST SEMINAR

WHO:    PROFESSOR DA-LIN ZHANG
        Department of Atmospheric and Oceanic Science
        University of Maryland
        College Park, MD

TITLE:  ON THE RAPID INTENSIFICATION OF HURRICANE WILMA (2005)

WHEN:   FRIDAY, MARCH 26, 2010 AT 2:00 PM

WHERE:  SLAB SEMINAR ROOM, SA 103
        SCIENCE AND ADMINISTRATION BLDG., RSMAS

***********************************************************************
ABSTRACT

In this study, a 72-hour cloud-resolving prediction of Hurricane Wilma
(2005), covering its initial 18-h spin up, an 18-h rapid deepening and the
subsequent 36-h weakening period, is performed using the Weather Research
Forecast (WRF) model with the finest grid length of 1 km. The model
initial and lateral boundary conditions, including its bogus vortex, are
taken from the Geophysical Fluid Dynamics Laboratory's then operational
forecast data, but with the specified daily sea-surface temperatures from
satellite observations.

It is shown that the WRF model prediction compares favorably to the best
track analysis, satellite, radar and reconnaissance flight observations as
well as the vortex message. In particular, the model reproduces Wilma?s
rapid intensity intensification (RI) rate of more than 7 hPa h-1 for a
12-h period, its minimum central pressure of less than 880 hPa, and the
subsequent weakening and reintensification in the surface maximum wind. Of
significance is that the model captures a sequence of important inner-core
structural changes associated with Wilma?s intensity variations, namely,
from a partial eyewall open to the west prior to RI to a full eyewall at
the onset of RI, rapid eyewall contraction during RI, the formation of
double eyewalls at the most intense stage, and the subsequent eyewall
replacement leading to the weakening of Wilma, followed by another eyewall
replacement cycle near the end of the 72-h prediction. In addition, the
model reproduces the polygonal eyewalls, and the boundary-layer growth up
to 750 hPa with an intense inversion layer above near the eye center.

Recognizing that a single case does not provide a rigorous test of the
model predictability, our results suggest that it is possible to improve
the forecasts of hurricane intensity and intensity changes if the
inner-core structural changes and storm size could be well predicted using
high-resolution cloud-resolving models with realistic initial conditions.




---------------------------------------------------------------------
Seminars and symposia at RSMAS

To unsubscribe, e-mail: seminar-unsubscribe@lists.rsmas.miami.edu
For additional commands, e-mail: seminar-help@lists.rsmas.miami.edu
Post to: seminar@rsmas.miami.edu