The step-change in surface properties along coastlines represents a special challenge for models. In particular, the model’s boundary-layer description needs to cope with very rapid transitions, often from unstable to stable conditions. Low-level wind-speed jets are frequent along many coastlines. Low-level wind maximums are also common in katabatic flows, often found over melting glaciers for example in the continental Arctic, and inertial low-level jets are often found in the Arctic boundary layer. In polar regions, the ice edge is basically a coastline from a meteorological perspective. Additionally, boundary-layer processes are here critical also since they are an important factor for ice drift and melt.

Common to these cases are complex wind-speed profiles, surface heterogeneity and stably stratified boundary layers. Situations where we perhaps expect models to have problems. In this presentation we intend to take step back and review our capability to model complex and stable boundary layers in coastal and Arctic environments in a broad context. We will be using field experiment data and modeling from the US west coast, Island and central Arctic from different projects to illustrate our capability to correctly describe the atmospheric boundary layer during such complex conditions.