A simple model of the convective internal boundary layer and its application to surface heat flux estimates within polynyas

• Main Authors: Renfrew, Ian A., King, John. C
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Kluwer 2000
• Subjects: Atmospheric Sciences; Sea ice
• Online Access: http://nora.nerc.ac.uk/id/eprint/502330/; https://doi.org/10.1023/A:1002492412097

A simple model of the convective (thermal) internal boundary layer has been developed for climatological studies of air-sea-ice interaction, where in situ observations are scarce and first-order estimates of surface heat fluxes are required. It is a mixed-layer slab model, based on a steady-state solution of the conservation of potential temperature equation, assuming a balance between advection and turbulent heat-flux convergence. Both the potential temperature and the surface heat flux are allowed to vary with fetch, so the subsequent boundary-layer modification alters the fluxconvergence and thus the boundary-layer growth rate. For simplicity, microphysical and radiative processes are neglected. The model is validated using several case studies. For a clear-sky cold-air outbreak over a coastal polynya the observed boundary-layer heights, mixed-layer potential temperatures and surface heat fluxes are all well reproduced. In other cases, where clouds are present, the model still captures most of the observed boundary-layer modification, although there are increasing discrepancies with fetch, due to the neglected microphysical and radiative processes. The application of the model to climatological studies of air-sea interaction within coastal polynyas is discussed.