Sensitivity of air-sea heat exchange to lead width and orientation as well as model resolution

Modeling air-sea interactions during cold air outbreaks poses a major challenge because of the vast range of scales and physical processes involved. Using the WRF model, we investigate the sensitivity of air mass transformation in an idealised cold air outbreak across a lead-fractured sea ice to (a) lead width, (b) lead orientation relative to the atmospheric flow, and (c) model resolution.

The extent to which leads are resolved in WRF strongly affects the overall air-sea heat exchange. In fact, even the direction of the heat exchange is dependent on model resolution. Further, the dependence of the overall heat exchange on model resolution is strongly non-linear, with the worst representation of the heat exchange through leads occuring when they are just about to become resolved by the model grid. In addition, the orientation of the leads relative to the atmospheric flow affects the air-sea heat exchange. Heat exchange is least effective when the leads are oriented perpendicular to the atmospheric flow.