Treatment of the Coriolis Terms in Semi-Lagrangian Spectral Models

Abstract

In a conventional three-time-level semi-Lagrangian scheme, the Coriolis terms are treated in an explicit centred fashion. This option is not available in a two-time-level scheme, and an alternative treatment must be sought. Two possible alternatives are tested here in the framework of a three-time-level scheme. Both are stable and accurate, but only one generalizes easily to a rotated coordinate system; this alternative is based on absorbing the Coriolis terms into the semi-Lagrangian advection.