Theme 3: Arctic-ocean-to-land

Northern land surfaces are affected by processes in the Arctic Ocean (e.g. reduced sea ice cover and regional feedbacks) and by direct advection of heat, humidity and substances (e.g. black carbon). The relative importance of both sources is explored in theme 1.

Here we will address the topic by analyzing budgets of heat and moisture in systematic sensitivity tests with e.g. artificially and locally reduced sea ice cover under conditions of recent climate and near future climate in RCAO and EC-Earth. This will allow for analysis of signal transfer mechanisms and for estimating a first order response on northern latitude land surface (in the LPJ_GUESS coupled component model) and other climate components. Previous work by Koenigk et al. (2008) with a global coupled GCM indicates a significant effect of Barents Sea ice changes on Northern Scandinavia and Russia, due to changes in the ocean heat release and consequent air temperature and atmospheric circulation changes.

Another link between the Arctic Ocean and land surface is through hydrological feedbacks in terms of river runoff. A new globally applicable prognostic river routing scheme has recently been introduced into RCAO and interactively connects land runoff with freshwater runoff into the ocean. The performance of this routing scheme in the Arctic will be evaluated by comparison with observations.

References

Koenigk, T., U. Mikolajewicz, J.H. Jungclaus, A. Kroll, 2008: Sea ice in the Barents Sea: seasonal to interannual variability and climate feedbacks in a global coupled model. Climate Dynamics, doi:10.1007/s00382-008-0450-2