Toward Understanding the Dynamics of Spinup in Emanuel’s Tropical Cyclone Model

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Montgomery, Michael T.
Smith, Roger K.
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Hurricanes
Mesoscale processes
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2019-10
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AMS
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Abstract
We seek to understand the mechanism of vortex spinup in Emanuel’s 2012 axisymmetric theory for tropical cyclone intensification in physical coordinates, starting from first principles. It is noted that, while spinup of the maximum tangential wind must occur at low levels, within or at the top of the friction layer, this spinup is unconstrained by a radial momentum equation in this layer. Instead, the spinup is controlled by a parameterization of turbulent mixing in the upper-tropospheric outflow layer, which, as is shown, determines indirectly the rate of inward movement of the absolute angular momentum surfaces. Nevertheless, the physics of how upper-tropospheric mixing leads to spinup in or at the top of the friction layer are unclear and, as discussed, may be irrelevant to spinup in the model.
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The article of record as published may be found at https://doi.org/10.1175/JAS-D-19-0051.1
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https://hdl.handle.net/10945/65297
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5 p.
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Montgomery, Michael T., and Roger K. Smith. "Toward Understanding the Dynamics of Spinup in Emanuel’s Tropical Cyclone Model." Journal of the Atmospheric Sciences 76.10 (2019): 3089-3093.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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