The vertical structure of tangential winds in tropical cyclones: theory vs. observations

In this study, three-dimensional Doppler wind analyses of several intense hurricanes are examined in an effort to gain some insight into the vertical structure of tropical cyclones. In particular, the decay of axisymmetric tangential winds both in the vertical and along sloping absolute angular momentum (M) surfaces are examined and compared to existing theoretical predictions. The slope of the Radius of Maximum Winds (RMW) is objectively determined and compared to the slope of the M surfaces. It is shown that in some cases, the observed vertical structure conforms with the expectations of theory, whereas in others it clearly does not. Examples are also presented which demonstrate that the slope of the RMW is not always a monotonic function of intensity or radius.

One of the primary goals of this research is to develop more realistic parameterizations for the vertical structure of tropical cyclones for use in idealized dynamics and modeling studies. Presently, most such studies specify vortices with entirely arbitrary vertical structures that have some unrealistic qualities. Some preliminary work towards developing realistic parameterizations will be presented.