Quasi-Stationary Waves in the Southern Hemisphere: An Examination of Their Simulation by the NCAR Climate System Model, with and without an Interactive Ocean

Abstract

The three primary quasi-stationary waves in the geopotential height field of the Southern Hemisphere, as simulated by the National Center for Atmospheric Research (NCAR) Climate System Model (CSM1) and the Community Climate Model, version 3 (CCM3), are examined and compared with the NCAR?National Centers for Environmental Prediction reanalyses. Fourier analysis is used to decompose the geopotential heights into its zonal harmonic components. Both models are able to simulate the mean and zonal asymmetry of the geopotential heights; however, the CSM1 simulates the interannual variability considerably better than the CCM3. The amplitude and phase of wave 1 are well simulated by the models, particularly in the subantarctic region. The models are also able to reproduce the interannual variation in phase and amplitude of wave 1. The success of the simulation is attributed to the models? ability to simulate well the important features of the geopotential height and temperature distributions. The models vary in their ability to simulate waves 2 and 3. Reasons for these variations are discussed.