Weather and climate in the Northern Hemisphere is profoundly affected by the Arctic Oscillation, a quasi-periodic fluctuation in atmospheric pressure that occurs on interannual to interdecadal timescales. Reconstructions of the Arctic Oscillation over longer timescales have suggested additional centennial- to millennial-scale variations in the phase of the oscillation, but often with conflicting results. Here we assess patterns of sea-ice drift in the Arctic Ocean over the past 8,000 years by geochemically determining the source of ice-rafted iron grains in a sediment core off the coast of Alaska. We identify pulses of sediment carried by sea ice from the Kara Sea, which can reach the coast of Alaska only during a strongly positive Arctic Oscillation. On the basis of these observations, we construct a record of the Arctic Oscillation phase, and identify a 1,500-year periodicity similar to that found in Holocene records of ice-rafted debrisin the North Atlantic, distinct from a 1,000-year cycle that has been found in total solar irradiance. We conclude that the 1,500-year cycle in the Arctic Oscillation arises from either internal variability of the climate system or as an indirect response to low-latitude solar forcing.
Darby, D., Ortiz, J., Grosch, C., & Lund, S. (2012). [Untitled]. Nature Geoscience. https://doi.org/10.1038/ngeo1629
Darby, Dennis, Joseph Ortiz, Chester Grosch, and Steven Lund. 2012. “[Untitled]”. Nature Geoscience. https://doi.org/10.1038/ngeo1629.
Darby, D., J. Ortiz, C. Grosch, and S. Lund. [Untitled]. Nature Geoscience, 1 Nov. 2012, doi:10.1038/ngeo1629.