The Generation and Maintenance of Hollow PV Towers in a Forced Primitive Equation Model†
AbstractDiabatic heating from deep moist convection in the hurricane eyewall produces a towering annular structure of elevated potential vorticity (PV), known as a hollow PV tower. For sufficiently thin annular structures, eddies can extract energy from the mean flow, leading to hollow tower breakdown with significant changes in vortex structure and intensity. A forced primitive equation model in isentropic coordinates is used to understand the role of diabatic heating in the generation, maintenance, and breakdown of the hurricane PV tower. It is shown that diabatic heating produces a strengthening and thinning PV tower in time due to the combined effects of the diabatic heating and the radial PV advection by the induced secondary circulation. If the forcing makes the eyewall thin enough, then the PV tower can become dynamically unstable and cause air parcels with high PV to be mixed preferentially into the eye at lower levels, where unstable PV wave growth rates are largest. The breakdown of the hollow PV tower leads to a transient break in vortex intensification, a decrease in minimum central pressure, and an inward shift and tilt of absolute angular momentum surfaces. It is shown that the maintenance of the PV tower structure depends on the strength of the heating-induced secondary circulation.
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Williams Jr., G.J. The Generation and Maintenance of Hollow PV Towers in a Forced Primitive Equation Model. Proceedings 2017, 1, 156.
Williams Jr. GJ. The Generation and Maintenance of Hollow PV Towers in a Forced Primitive Equation Model. Proceedings. 2017; 1(5):156.Chicago/Turabian Style
Williams Jr., Gabriel J. 2017. "The Generation and Maintenance of Hollow PV Towers in a Forced Primitive Equation Model." Proceedings 1, no. 5: 156.
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