On the use of energy balance models with an underlying ocean

By Riccardo Farneti and Peter D. Killworth

Southampton Oceanography Centre, Southampton, United Kingdom


This paper shows the existence of an erroneous growing planetary-wavelike ocean mode, with a decadal period and growth rate, which appears when a stratified, diffusive ocean is coupled to a simple atmosphere via an energy balance model (EBM). Such modes are not found when simpler surface ocean conditions are applied. The mode is low order in the vertical and, because of its slow growth, is likely to be observed in Earth System Models using an EBM in place of a fuller set of atmospheric dynamics. There is no physical energy source for such a mode. The mode is analysed through a hierarchy of simple models which differ only through their surface boundary condition.