On The Evaluation of the Role of Large-Scale Control in Arctic Surface Heat Flux Parameterizations

Traditionally, surface flux parameterization development has focused on the issue of fidelity, of how to represent the nuances of the physical processes acting in the atmospheric boundary layer and in the sea ice. Much of the work and discussion in improving surface heat flux parameterization has revolved around the inclusion of additional physical processes and variability; in the Arctic some of these issues include surface roughness changes due to ice ridging, albedo changes due to melt ponds, and sensible and latent heat flux effects of leads and polynyas.

Less explicit attention though has been paid to the evaluation of surface flux parameterizations as parameterizations, that is as a description of how well the parameterizations describe sub-grid phenomena and their interactions with the large-scale in terms of the large-scale variables. In the current work, measurements of surface fluxes taken by the Atmospheric Surface Flux Group (ASFG) and values derived from ECMWF reanalyses, both taken as part of the Surface Heat Budget of the Arctic Ocean Experiment (SHEBA) are analyzed to provide a first-cut, exploratory look at how well current "state-of-the-practice" parameterizations function as parameterizations. Preliminary results suggest that for most terms of the surface energy budget, while various features of local timeseries are reasonably captured by current parameterizations, such parameterizations do not adequately represent large-scale control of the sub-grid phenomena.