Advances in regional climate modelling must be strongly based on analysis of physical processes in comparisonwith data. In a data-poor region such as the Arctic, this procedure may be enhanced by a community-basedapproach, that is, though collaborative analysis by several research groups. To illustrate this approach,simulations were performed with two regional climate models HIRHAM and ARCSyM, over the Arctic basin to65oN, laterally driven at the boundaries by observational analyses. It was found that both models are able toreproduce reasonably the main features of the large-scale flow and the surface parameters in the Arctic. Distinctdifferences in the simulations can be attributed to specific characteristics of the boundary layer and surfaceparameterizations which result in surface flux differences, and to the lateral moisture forcing, both of which affectmoisture availability in the atmosphere. Further disparities are associated with the additional degrees of freedomallowed in the coupled model ARCSyM. Issues of model configuration and experimental design are discussed,including domain size, grid spacing, boundary formulations, model initialization and spinup, and ensemble approaches. In order to reach definitive conclusions in a regional climate model intercomparison, ensemble simulationswith adequate spin-up and equivalent initialization of surface fields will be required.
AWI Organizations > Climate Sciences > Observational Oceanography
AWI Organizations > Climate Sciences > Climate Dynamics
AWI Organizations > Climate Sciences > Sea Ice Physics