A 200-year Sulfate Record from 16 Antarctic Ice Cores and Associations with Southern Ocean Sea Ice Extent

Daniel A. Dixon

As of 2002, Degree of Master of Science (MS) Quaternary and Climate Studies published under the auspices of the Climate Change Institute.


Data from sixteen, 50m- to 115m-deep, sub-annually dated ice cores are used to examine the recent spatial and temporal concentration variability of sea salt (ss)S04 " and excess (xs)S04 " over West Antarctica for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than one year based on known global scale volcanic events. A dual transport source for West 9 9 Antarctic SSSO4 " and XSSO4 " is observed: lower tropospheric for areas below 1000m elevation and mid-upper tropospheric/stratospheric for areas located above 1000m. The XSSO4 " records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West Antarctic SO4 ' concentrations but do reveal that a major climate transition takes place over West Antarctica -1940. Global-scale volcanic eruptions appear as significant peaks in the robust spline residual XSSO4 " records from sites located above 1000m elevation but do not appear in the residual records from sites located below 1000m. These high-resolution records show that the controls on ss- and XSSO42" deposition vary from site to site and can only be resolved using the type of framework of ice core records available from the International Trans-Antarctic Scientific Expedition (ITASE). Sources of SO42" from Ross Sea sea ice and Ross Sea Polyna primary production, combined with transport over the Ross Ice Shelf via frequent cyclogenesis, significantly increases the net transport of SSSO42" and XSSO42" aerosols to low elevation sites in western West Antarctica. Based on linear correlation analysis, ssS04 " concentrations are higher when sea ice extent (SIE) is greater, and XSSO4 " concentrations are higher when SIE is lesser. The South Pole receives the majority of its XSSO4 " from different sources than the rest of West Antarctica, and the Weddell region may be a significant source of aerosol chemistry for eastern West Antarctic sites.