Some numerical calculations of the vertical velocity field in hurricanes

The commonly observed crescent-shaped geometry of the tangential wind field in hurricanes is imposed on the primitive equations of atmospheric motion, and solutions for the vertical velocity field are obtained. It is shown that the numerically computed vertical motion field exhibits a spiral form, very similar to what is observed in radar pictures in individual hurricanes.

Aircraft flight data from the National Hurricane Research Project are utilized to carry out the numerical calculations in several hurricanes over the Atlantic.

An attempt is made to obtain an analytic solution for the same complete system of equations for a generalized Rankine vortex with a prescribed crescent-shaped geometry. It is shown that the analytic solution has an interesting spiral form. This solution for the Rankine vortex is compared with the corresponding finite difference solution to estimate the errors in the finite difference solution.