The role of ocean waves and SST in seasonal variability

We construct a model for atmosphere-ocean wave coupled dynamics, implemented regionally for the North Atlantic. Time-scales ranging from synoptic to seasonal are considered. The model system consists of the NCAR RegCM2 climate model and the WAM ocean wave model. The sea-state dependent sea surface roughness Zo parameterization derived by Smith et al. (1992) in the HEXOS North Sea experiment provides the coupling mechanism. Verification of the model system is achieved, using the recent LSDCE (Labrador Sea Deep Convection Experiment) data. We show that atmosphere-wave coupling has impact on both waves and atmospheric dynamics. Specifically, the coupled model system exhibits enhanced forecast capability, compared to uncoupled simulations. This enhancement includes an intensification of storm systems, typified by deeper low pressure depressions and elevated wind stress fields.