EMAD: an empirical model of air-sea fluxes

An empirical model of daily fluxes at the sea surface is proposed. The model, referred to as EMAD (Empirical Model of Atmospheric Dynamics), concentrates on the linear dynamics of the time-varying part of the air-sea fluxes. It is based on a general formulation that allows different types of air-sea interactions depending on the relative dominance of the model parameters. The parameters are obtained by fitting the model to a long integration with a coupled atmosphere ocean general circulation model. EMAD is able to reproduce air-sea interactions found in a coupled general circulation model. In particular, EMAD reveals realistic stationary responses to different sea surface conditions. The variance distributions produced by EMAD are comparable to those obtained from an integration with a coupled general circulation model. Finally, the characteristic air-sea interactions as described by the cross-correlation functions and found in an integration with a coupled general circulation model are captured by EMAD. Given these properties of EMAD, the ocean circulation and its variability can be studied using an ocean general circulation model driven by EMAD.