A 200 year sub-annual record of sulfate in West Antarctica, from 16 ice cores

Sixteen high-resolution ice-core records from West Antarctica and South Pole are used to examine the spatial and temporal distribution of sulfate for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than 1 year based on known global-scale volcanic events. A dual transport source for West Antarctic sea-salt (ss) SO4 2– and excess (xs) SO4 2– is observed: lower-tropospheric for areas below 1000m elevation and mid-/upper-tropospheric/stratospheric for areas located above 1000 m. Our xsSO4 2– records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West Antarctic SO4 2– concentrations but do reveal that a major climate transition takes place over West Antarctica at ∼1940. Global-scale volcanic eruptions appear as significant peaks in the robust-spline residual xsSO4 2– records from sites located above 1000m elevation but do not appear in the residual records from sites located below 1000 m.