A 200 year sulfate record from 16 Antarctic ice cores and associations with Southern Ocean sea-ice extent

Chemistry data from 16, 50–115 m deep, sub-annually dated ice cores are used to investigate spatial and temporal concentration variability of sea-salt (ss) SO4 2– and excess (xs) SO4 2– over West Antarctica and the South Pole for the last 200 years. Low-elevation ice-core sites in western West Antarctica contain higher concentrations of SO4 2– as a result of cyclogenesis over the Ross Ice Shelf and proximity to the Ross Sea Polynya. Linear correlation analysis of 15 West Antarctic ice-core SO4 2– time series demonstrates that at several sites concentrations of ssSO4 2– are higher when sea-ice extent (SIE) is greater, and the inverse for xsSO4 . Concentrations of xsSO4 2– from the South Pole site (East Antarctica) are associated with SIE from the Weddell region, and West Antarctic xsSO4 2– concentrations are associated with SIE from the Bellingshausen–Amundsen–Ross region. The only notable rise of the last 200 years in xsSO4 , around 1940, is not related to SIE fluctuations and is most likely a result of increased xsSO4 2– production in the mid–low latitudes and/or an increase in transport efficiency from the mid–low latitudes to central West Antarctica. These high-resolution records show that the source types and source areas of ssSO4 2– and xsSO4 2– delivered to eastern and western West Antarctica and the South Pole differ from site to site but can best be resolved using records from spatial ice-core arrays such as the International Trans-Antarctic Scientific Expedition (ITASE).