Clim. Past Discuss., 9, 3125-3174, 2013
© Author(s) 2013. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper is under review for the journal Climate of the Past (CP).
Centennial-scale shifts in the position of the Southern Hemisphere westerly wind belt over the past millennium
B. G. Koffman1,2,*, K. J. Kreutz1,2, D. J. Breton2,3,**, E. J. Kane1, D. A. Winski1,2,***, S. D. Birkel2, A. V. Kurbatov1,2, and M. J. Handley2
1School of Earth and Climate Sciences, University of Maine, 5790 Bryand Global Sciences Center, Orono, ME 04469, USA
2Climate Change Institute, University of Maine, 300 Bryand Global Sciences Center, Orono, ME 04469, USA
3Department of Physics and Astronomy, Bennett Hall, University of Maine, Orono, ME 04469, USA
*now at: Lamont-Doherty Earth Observatory of Columbia University, P.O. Box 1000, 61 Route 9W, Palisades NY, 10964, USA
**now at: Thayer School of Engineering, Dartmouth College, 14 Engineering Drive, Hanover, NH 03755, USA
***now at: Stantec Consulting Inc., 100 Pearl Street, 11th Floor, Hartford, CT 06103, USA

Abstract. We present the first high-resolution (sub-annual) dust particle dataset from West Antarctica, developed from the West Antarctic Ice Sheet (WAIS) Divide deep ice core (79.468° S, 112.086° W), and use it to reconstruct past atmospheric circulation. We find a background dust flux of ∼4 mg m−2 yr−1 and a mode particle size of 5–8 μm diameter. Through comparison with other Antarctic ice core particle records, we observe that coastal and lower-elevation sites have higher dust fluxes and coarser particle size distributions (PSDs) than sites on the East Antarctic plateau, suggesting input from local dust sources at lower elevations and sites closer to the coast. In order to explore the use of the WAIS Divide dust PSD as a proxy for past atmospheric circulation, we make quantitative comparisons between mid-latitude zonal wind speed and the dust size (coarse particle percentage, CPP) record, finding significant positive interannual relationships. Using our CPP record, and through comparison with spatially distributed climate reconstructions from the Southern Hemisphere (SH) middle and high latitudes, we infer latitudinal shifts in the position of the SH westerly wind belt during the Medieval Climate Anomaly (MCA; ∼950–1350 C.E.) and Little Ice Age (LIA; ∼1400–1850 C.E.) climate intervals. We suggest that the SH westerlies occupied a more southerly position during the MCA, and shifted equatorward at the onset of the LIA (∼ 1430 C.E.) due to cooler surface temperatures and a contraction of the SH Hadley cell.

Citation: Koffman, B. G., Kreutz, K. J., Breton, D. J., Kane, E. J., Winski, D. A., Birkel, S. D., Kurbatov, A. V., and Handley, M. J.: Centennial-scale shifts in the position of the Southern Hemisphere westerly wind belt over the past millennium, Clim. Past Discuss., 9, 3125-3174, doi:10.5194/cpd-9-3125-2013, 2013.
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