Toward Understanding the Dynamics of Spinup in Emanuel’s Tropical Cyclone Model
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2019
- Source ID
- 10.1175/jas-d-19-0051.1
Entities
People
- Michael T. Montgomery
- Roger K. Smith
Organizations
- Ludwig-Maximilians-Universität München
- National Science Foundation
- Naval Postgraduate School
- Office of Naval Research