Numerical Tendency Computations from the Barotropic Vorticity Equation

As a preliminary test of the usefulness of the barotropic vorticity equation for numerical forecasting a series of tendency computations have been made for a period of ten days in February 1951. Despite the difficulty of comparing instantaneous tendencies with observed changes over a finite time interval (12 hours) some positive information was obtained concerning computational errors as well as errors in the atmospheric model. The computations support the conclusion reached by CHARNEY and ELIASSEN (1949) that the Rocky Mountains are of importance in their influence on the large scale upper level flow pattern over the United States.