P2D.8 The modulation of tropical cyclone structure and intensity by evolving outflow layer environmental flow

Thursday, 1 May 2008
Palms ABCD (Wyndham Orlando Resort)
Eric D. Rappin, University of Miami, Miami, FL; and G. J. Tripoli and M. C. Morgan

The purpose of this study is to gain deeper insight into the response of the tropical cyclone (TC) core to organized, asymmetric outflow. Recent work has shown how an ensemble of convective clouds could utilize low outflow layer inertial stability to produce rapid intensification of idealized TCs. We hypothesize that the connection between TC structure and the surrounding environment is the TC outflow. That is, updrafts organize such that the angular momentum transports within the core give TC outflow access to weak inertial stability in the environment. This in turn minimizes a significant TC energy sink and, in the absence of other sinks, permits intensification to near the maximum potential intensity.

High resolution simulations using a cloud resolving model are applied to the case of super typhoon Ma-On (2004), a TC evolution that bore remarkable similarity to previous simulations completed by the author. Simulations with and without the planetary trough-jet couplet are performed to gauge the environmental impact on intensification. Angular momentum budgets are provided to assess environmental influence on cloud and eyewall structure.

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