Surface Heat and Moisture Exchange in the Marginal Ice Zone: Observations and a New Parameterization Scheme for Weather and Climate Models

Aircraft observations from two Arctic field campaigns are used to characterize and model surface heat moisture exchange over the marginal ice zone (MIZ). We show that roughness lengths for uninterrupted sea vary with Reynolds number (; itself a function of length momentum, , wind stress), peak at transition between aerodynamically smooth (<0.135) rough (>2.5) regimes. A pre-existing theoretical based on surface-renewal theory accurately reproduces this peak, in contrast simple parameterizations currently employed state-of-the-art numerical weather prediction models, which insensitive . propose new, parameterization MIZ blends water as concentration. In offline tests, new scheme performs much better than existing schemes conditions observed during ‘Iceland Greenland Seas Project’ campaign. The bias total turbulent flux across is reduced only 13 W m?2 scheme, 48 80 Met Office Unified Model ECMWF Integrated Forecast System schemes, respectively. It also marginally comparatively ‘Aerosol-Cloud Coupling Climate Interactions Arctic’ has benefit being physically-motivated, accurate straightforward implement, although reap full benefits an improvement representation topography via required.