Use of the Vorticity Equation in Dual-Doppler Analysis of the Vertical Velocity Field

Abstract

Abstract The anelastic vertical vorticity equation is imposed as a flow constraint in dual-Doppler wind analysis techniques, with emphasis on improving retrievals of the vertical velocity field. Several new techniques in which the vorticity equation is imposed as a weak constraint are presented. In one method, the vorticity equation is used to obtain the vertical velocity boundary condition field required when mass continuity is used as a strong constraint. In a second method, the vorticity equation is used to solve for the set of two boundary condition fields required when the vertical velocity is expressed in a “weak constraint form.” A final correction step to the horizontal wind field ensures that mass continuity is satisfied exactly in the final analysis. This latter method can be easily adapted to retrieve a single boundary condition when an opposing boundary condition can be accurately assessed using another method. These new analysis techniques are tested and compared with each other and to common...