On the Discretization of the Continuity Equation in Semi-Lagrangian Models with a Pressure-Type Vertical Coordinate

Abstract

This note presents an alternative way to perform discretization of the column-integrated continuity equation in pressure-type vertical coordinate semi-Lagrangian models. The properties of this alternative form have not yet been pointed out in the literature to the authors' knowledge, and the aim of this paper is to briefly review some of its potential advantages or disadvantages for NWP modeling, namely with respect to behavior with mountains and to mass-conservation properties.