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How Well Do Climate Models Mimic Atmospheric Teleconnections?

Reference
Handorf, D. and Dethloff, K. 2012. How well do state-of-the-art atmosphere-ocean general circulation models reproduce atmospheric teleconnection patterns? Tellus A 64: org/10.3402/tellusa.v64i0.19777.
According to Handorf et al. (2012), "atmospheric teleconnections describe important aspects of the low-frequency atmospheric variability on time-scales of months and longer," and they say that "in light of the increased need to provide reliable statements about seasonal to decadal predictability, it is necessary that state-of-the-art climate models simulate the spatial and temporal behavior of atmospheric teleconnections satisfactorily." And, therefore, as they continue, "an evaluation of climate models requires the evaluation of the simulated climate variability in terms of teleconnection patterns."

Against this backdrop, Handorf and Dethloff evaluated "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." This they did using the CMIP3 multi-model ensemble for the period 1958-1999, for which reliable re-analysis data were available for comparison. So what did they learn from this exercise?

When all was said and done, the two researchers concluded that "current state-of-the-art climate models are not able to reproduce the temporal behavior, in particular the exact phasing of the dominant patterns due to internally generated model variability." In addition, they concluded that "the state-of-the-art climate models are not able to capture the observed frequency behavior and characteristic time scales for the coupled runs satisfactorily ... in accordance with Stoner et al. (2009) and Casado and Pastor (2012)," both of which studies concluded, in their words, that "the models are not able to reproduce the temporal characteristics of atmospheric teleconnection time-series."

Based on their study, and "in light of the strong need to provide reliable assessments of decadal predictability," Handorf and Dethloff state that "the potential of atmospheric teleconnections for decadal predictability needs further investigations" that "require a better understanding of [1] the underlying mechanisms of variability patterns and flow regimes, [2] an improvement of the skill of state-of-the-art climate and Earth system models in reproducing atmospheric teleconnections and [3] the identification of sources for long-range predictive skill of teleconnecdtions," all of which requirements clearly suggest that we aren't there yet, in terms of doing what needs to be done.

Additional References
Casado, M. and Pastor, M. 2012. Use of variability modes to evaluate AR4 climate models over the Euro-Atlantic region. Climate Dynamics 38: 225-237.

Stoner, A.M.K., Hayhoe, K. and Wuebbles, D.J. 2009. Assessing general circulation model simulations of atmospheric teleconnection patterns. Journal of Climate 22: 4348-4372.

Archived 15 May 2013