How well do state-of-the-art atmosphere-ocean general circulation models reproduce atmospheric teleconnection patterns?

Abstract

This article evaluates the ability of state-of-the-art climate modelsto reproduce the low-frequency variability of the mid-troposphericwinter flow of the Northern Hemisphere in terms of atmospheric teleconnectionpatterns. Therefore, multi-model simulations for present-day conditions,performed for the 4th assessment report of the IntergovernmentalPanel on Climate Change, have been analysed and compared with re-analysisdata sets. The spatial patterns of atmospheric teleconnections arereproduced reasonably by most of the models. The comparison of coupledwith atmosphere-only runs confirmed that a better representationof the forcing by sea surface temperatures has the potential to slightlyimprove the representation of only wave train-like patterns. Dueto internally generated climate variability, the models are not ableto reproduce the observed temporal behaviour. Insights into the dynamicalreasons for the limited skill of climate models in reproducing teleconnectionshave been obtained by studying the relation between major teleconnectionsand zonal wind variability patterns. About half of the models areable to reproduce the observed relationship. For these cases, thequality of simulated teleconnection patterns is largely determinedby the quality of zonal wind variability patterns. Therefore, improvementsof simulated eddy-mean flow interaction have the potential to improvethe atmospheric teleconnections.