Kinematic analysis of upper wind fields

Abstract

The paper explains a method of computing the velocity and direction of movement of trough-experiment a lines, cyclonic centres etc associated with upper wind fields by evaluating vectorial changes of wind with time. The method is similar to the one first proposed for surface pressure fields by Petterssen, but has the advantages that it can be used for any level for which sufficient wind data are available. The displacement of a trough line in a pressure field is obtained by Petterssen In terms of pressure derivatives of the second order; In the present paper It is shown that the displacement of a trough line in a wind field is obtained in terms of wind velocity derivatives of the first order. The inaccuracy of upper wind data as compared to surface pressure data is somewhat offset by the lower order of the terms in the equations for the displacement of troughlines.