Climate Studies with a Multi-Layer Energy Balance Model. Part I: Model Description and Sensitivity to the Solar Constant

Abstract

Abstract A nine-layer, zonally averaged, steady-state model has been developed for use in climate sensitivity studies. The model is based upon thermal energy balance and includes recently developed accurate treatment of radiative transfer, parameterized meridional and vertical energy transport, and thermodynamic interaction between the surface and the atmosphere. Cloud cover and relative humidity are prescribed parameters. Using present day boundary conditions for the Northern Hemisphere, the simulated temperature field, heat fluxes and radiation quantities are in good agreement with observations. In a study of sensitivity to changes in the solar constant, the model exhibits a high degree of nonlinearity. The change in the hemispheric mean surface temperature is +3.1°C in response to a 2% increase in the solar constant and −4.3°C in response to a 2% decrease in the solar constant. The sensitivity varies with latitude. In the polar region it is about three times larger than in the tropics, due mostly to th...