Current research in air-sea interaction is attempting to apply our understanding of molecular and turbulence scale processes to global scale phenomena. There are many unknowns in the fundamental processes that control the global climate. For example, what processes control the amount and distribution of water in the atmosphere; what is the effect of cloud variability on the sea surface temperature? How do changes in the ocean circulation affect the atmospheric circulation and, hence, the distribution of wind stress, temperature and precipitation, and how does this feed back to the ocean? These, and many other related questions, form the rationale for some of the studies of the interaction of the atmosphere and the ocean.
Major uncertainties remain in our understanding of the fundamental processes of air-sea interaction, particularly, in heterogeneous and nonequilibrium conditions; for example, we do not know enough about the relationships between the directional wave spectra, surface fluxes and the properties of the oceanic and atmospheric boundary layers to develop satisfactory predictive models. The ocean and atmosphere are interdependent, or coupled, because of the dependence of the atmosphere on heat and moisture at the sea surface and the dependence of the ocean circulation on the wind. Studies rarely combine investigations of both environments to determine the extent of the fedbacks between the ocean and the atmosphere. Understanding the coupled ocean-atmosphere system depends largely on the scales of interaction between the two fluids and the processes that provide the strongest feedbacks. Advances are most likely through multidisciplinary process studies that connect the upper ocean and lower atmosphere.
For global studies more comprehensive parameterizations of the surface processes are required as well as improvements in satellite retrievals and assimilation in numerical models. The high spatial and temporal variability of surface processes needs to be properly considered. In situ measurements are revealing very complex horizontally and vertically heterogeneous fields that cannot be resolved by current remote sensing techniques. High resolution models, which include the physics of the processes that contribute to this variability, combined with satellite data seems to offer the best opportunity to provide global analysis and prediction.
Acknowledgments. This work was supported by the Office of Naval Research, Marine Meteorology Program (N00014-90-J-1265 and N00014-94-I-0232).