This paper evaluates the ability of state-of-the-art climate models to
reproduce the low-frequency variability of the mid-tropospheric winter
flow of the Northern Hemisphere in terms of atmospheric teleconnection
patterns. Therefore, multi-model simulations for present day
conditions, performed for the 4th assessment report of the
Intergovernmental Panel on Climate Change have been analysed and
compared with reanalysis data sets.

The spatial patterns of atmospheric teleconnections are reproduced
reasonably by most of the models. The comparison of coupled with
atmosphere-only runs confirmed that a better representation of the
forcing by sea surface temperatures has the potential to slightly
improve the representation of only wave train-like patterns. Due to
internally generated climate variability, the models are not able to
reproduce the observed temporal behaviour.

Insights into the dynamical reasons for the limited skill of climate
models in reproducing teleconnections have been obtained by
studying the relation between major teleconnections and zonal wind
variability patterns. About half of the models are able to
reproduce the observed relationship. For these cases, the quality of
simulated teleconnection patterns is largely determined by the quality of
zonal wind variability patterns. Therefore, improvements of
simulated eddy-mean flow interaction have the potential to improve the
atmospheric teleconnections.

Full Article: http://www.tellusa.net

Last Updated: 2012-12-04