THE NUMERICAL PREDICTION OF HURRICANE
MOVEMENT WITH THE BAROTROPIC MODEL
University of Chicago
(Manuscript received January 10, 1957, in final form May 8,
In order to increase the accuracy of prediction of hurricane
movement beyond that which has been obtained with methods now
in use, a numerical procedure based upon the barotropic model
is presented here.
A vortex field is separated from the total flow to obtain the
residual-steering flow field. By solving the equation for the
steering field, which does not include any parameters related
to the vortex, the prediction of the steering flow is executed
in the ordinary manner.
By solving the other equation, which includes the interaction
terms between the hurricane and the steering flow, the movement
of the vortex pattern is predicted. To make the latter problem
more tractable, a velocity formula for the movement of the vortex
center is derived on the basis of a few reasonable assumptions
concerning the structure of the vortex and of the steering field.
The variables in the formula are expressed only in terms of
quantities determined by the steering field and a single characteristic
parameter related to the scale of the hurricane. By this means,
a forecast of the hurricane movement can be programmed as a
subroutine which is executed in the course of the prediction
of the steering flow.
Five cases of predicting the 24-hour and 48-hour movements of
hurricane iane?and onnie?(August 1955) at the 500-mb level
are presented here. These results have been obtained by the
use of a high-speed computer, from initial maps which were be-analyzed
using all available data.