Abstract: The temporal variability and spatial pattern of the Arctic Oscillation (AO) simulated in the historical experiment of 26 coupled climate models participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5) were evaluated. Spectral analysis of the monthly AO time series indicates that 23 out of 26 of the CMIP5 models exhibit no statistically significant spectral peak in the historical experiment, as seen in the observed time series. Also, these models are able to reproduce the AO pattern in the sea level pressure anomaly field during boreal winter. But the strength of AO pattern tends to be overestimated in all the models. The zonal-mean zonal wind anomalies associated with the winter AO exhibit a dipole in latitude, which is only well reproduced by a few models. Most models show significant biases in both strength and location of the meridional dipole in the zonal-mean zonal wind anomaly filed associated with the winter AO. In considering the temporal variability as well as spatial structures in both horizontal and vertical directions, the model MPI-ESM-P reproduces an AO pattern that more resembles the observation.

Key words: Arctic Oscillation, model evaluation, coupled climate model, CMIP5