Further Development and Applications of an Efficient and Configurable Vortex Initialization Technique

Building from a highly configurable vortex initialization method for tropical cyclones that was previously developed at RSMAS, a new efficient Fortran 90 version of the software has been completed.

Some of the tunable parameters for the synthetic vortex are the radius of maximum wind, maximum wind speed, boundary layer depth, vortex depth, radial structure, vertical structure, and inner core moisture. The vortex is in gradient wind and hydrostatic balance, but is not balanced with the environment.

Previous work with this technique has shown that there is little sensitivity to whether the bogus vortex is balanced with the environment. In fact, many models which employ sophisticated vortex initialization methods still suffer from dramatic initial spin-down of the winds during dynamic adjustment.

We plan on running experiments using WRF and COAMPS-TC on real storm cases to isolate any features of the initial vortex that enhance or suppress the initial dynamic adjustment.

This software is available to the community. It is already being utilized as a research tool at the Naval Research Laboratory in Monterey to help improve the operational COAMPS-TC hurricane model, and is also being modified for possible use with polar vortices.