Katabatic Wind‐Driven Exchange in Fjords Journal of Geophysical Research: Oceans

The general issue of katabatic wind-driven exchange in fjords is considered using an idealized numerical model, theory, and observations. Two regimes are identified. For fjords narrower than a viscous boundary layer width, the exchange is limited by a balance between wind and friction in lateral boundarylayers. For the nonlinear viscous parameterization used here, this boundary layer thickness depends on the properties of the fjord, such as stratification and length, as well as on the wind stress and numerical parame- ters such as grid spacing and an empirical constant. For wider fjords typical of east Greenland, the balanceis primarily between wind, the along-fjord pressure gradient, and acceleration, in general agreement with previous two-layer nonrotating theories. It is expected that O(10%) of the surface layer will be flushed out of the fjord by a single wind event. Application of the idealized model to a typical katabatic wind event produ-ces outflowing velocities that are in general agreement with observations in Sermilik Fjord, a large glacial