A New Finite-Differencing Scheme for the Tracer Transport Equation

Abstract

A new finite-differencing scheme for solving the tracer transport equation given prescribed winds is presented. The prognostic quantities predicted by the new scheme are the mean concentration and its spatial gradients. In one and two-dimensional tests using uniform air masses, the new scheme is roughly comparable to a fourth-order differencing scheme in accuracy. When the air masses are not uniform, the new scheme is superior to fourth-order differencing. An application of the schemes to three-dimensional tracer modeling is included.