Extended Abstract (1.4M)25.4
Dependence of Hurricane Intensity and Structures on Vertical Resolution
Da-lin Zhang, University of Maryland, College Park, MD; and X. Wang
In view of the growing interests in the explicit modeling of clouds and precipitation, the effects of varying vertical resolution on the 72-h explicit simulation of Hurricane Andrew (1992) are studied using the PSU/NCAR mesoscale model (i.e., MM5) with the finest grid size of 6 km.
It is found that changing vertical resolution has significant effects on hurricane intensity and inner-core cloud/precipitation, but little impact on the hurricane track. In general, increasing vertical resolution tends to produce a deeper storm with lower central pressure and stronger three-dimensional winds, and more precipitation. It is also found that increasing the low-level vertical resolution is more efficient in intensifying a hurricane, whereas changing the upper-level vertical resolution has little impact on the hurricane intensity. Moreover, the use of a thicker surface layer tends to produce higher maximum surface winds. It is concluded that the use of higher vertical resolution, a thin surface layer and smaller time-step sizes, along with higher horizontal resolution, is desirable to model more realistically the intensity and inner-core structures and evolution of tropical storms as well as the other convectively driven weather systems.
Session 25, Model Numerics
Thursday, 15 January 2004, 3:30 PM-5:00 PM, Room 607
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