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  • The Intensity-dependence of Tropical Cyclone Intensification Rate in a Simplified Energetically Based Dynamical System Model
Title: The Intensity-dependence of Tropical Cyclone Intensification Rate in a Simplified Energetically Based Dynamical System Model
Abstract In this study, a simple energetically based dynamical system model of tropical cyclone (TC) intensification is modified to account for the observed dependence of the intensification rate (IR) on the storm intensity. According to the modified dynamical system model, the TC IR is controlled by the intensification potential (IP) and the weakening rate due to surface friction beneath the eyewall. The IP is determined primarily by the rate of change in the potential energy available for a TC to develop, which is a function of the thermodynamic conditions of the atmosphere and the underlying ocean, and the dynamical efficiency of the TC system. The latter depends strongly on the degree of convective organization within the eyewall and the inner-core inertial stability of the storm. At a relatively low TC intensity, the IP of the intensifying storm is larger than the frictional weakening rate, leading to an increase in the TC IR with TC intensity in this stage. As the storm reaches an intermediate intensity of 30-40 m s -1 , the difference between IP and frictional weakening rate reaches its maximum, concurrent with the maximum IR. Later on, the IR decreases as the TC intensifies further because the frictional dissipation increases with TC intensity at a faster rate than the IP. Finally, the storm approaches its maximum potential intensity (MPI) and the IR becomes zero. The modified dynamical system model is validated with results from idealized simulations with an axisymmetric nonhydrostatic, cloud-resolving model.  more » « less
Award ID(s):
1834300
PAR ID:
10318112
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Journal of the Atmospheric Sciences
ISSN:
0022-4928
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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