Some Basic Dynamics Relevant to the Design of Atmospheric Model Dynamical Cores

Abstract

The dynamics of the global atmosphere is highly complex and multiscale. In this chapter a few aspects are discussed that are considered especially important for the design of numerical models of the atmosphere. Commonly used approximations to the governing equations are discussed. The dynamics of fast acoustic and inertio-gravity waves is briefly explained along with their role in maintaining the atmosphere close to hydrostatic and geostrophic balance. The balanced dynamics is exemplified through quasigeostrophic theory, which embodies the key ideas of advection and invertibility of potential vorticity. Finally, some important effects of nonlinearity are discussed, in particular the interaction between different scales and the transfer of energy and potential enstrophy across scales.