The intraseasonal evolution of angular momentum in aquaplanet and realistic GCMs

Abstract

This paper describes the evolution of global angular momentum (GAM) on intraseasonal timescales in data from two general circulation model (GCM) runs: an aquaplanet GCM and a fully "realistic' GCM that includes continents, topography, and observed climatological sea surface temperatures. For both GCMs, the angular momentum budget is quite well balanced. Composite analysis shows that the GAM tendency is largest as a precipitation anomaly propagates eastward along the equator. Associated with the precipitation anomaly is a tropical circulation that shows some of the characteristics of the Gill model, particularly in the aquaplanet GCM, and a Rossby wave train that propagates from the Tropics into midlatitudes. -from Authors