Is the observed NAO variability during the instrumental record unusual?
نویسندگان
چکیده
[1] Observed multidecadal variability (30 yr runningmeans, trends, and moving standard deviations) of the North Atlantic Oscillation (NAO) during the instrumental record is compared to that simulated by two different coupled general circulation models in extended-range control experiments. Simulated NAO exhibits strong low frequency fluctuations, even on multi-centennial time scale. Observed multi-decadal NAO variations agree well with the model variability. Trend probability distribution functions, observed and simulated, were not found to be different with statistical significance. Thus, multi-decadal NAO changes similar to those observed during the instrumental record, including the recent increase in 1965–1995, may be internally generated within the coupled atmosphere-ocean system without considering external forcing. Citation: Semenov, V. A., M. Latif, J. H. Jungclaus, and W. Park (2008), Is the observed NAO variability during the instrumental record unusual?, Geophys. Res. Lett., 35, L11701, doi:10.1029/2008GL033273.
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