ON THE CONSERVATION OF FINITE-DIFFERENCE ABSOLUTE VORTICITY IN BAROTROPIC FORECASTS

Abstract

In solving the differential equations used in numerical weather prediction, one resorts to the use of finite-difference techniques. In the barotropic model it is assumed that the absolute vorticity is conserved. Even though the differential form of the vorticity equation insures conservation, the finite-difference form may not. The purpose of this study is to test this assumption in order to find out how serious truncation errors really are. The results indicate that the finite-difference absolute vorticity is reasonably well conserved, at least up to 48 hours.