Sulfur cycle at Last Glacial Maximum: Model results versus Antarctic ice core data

For the first time, an atmospheric general circulation and sulfur chemistry model is used to simulate sulfur deposition in Antarctica at the Last Glacial Maximum (LGM). Dimethylsulfide (DMS), emitted by phytoplankton, is the dominant source of atmospheric sulfur in Antarctica. Once in the atmosphere, it is oxidized into sulfur aerosols which are measured in ice cores. Such measurements allow for validating climate and chemistry models for glacial-interglacial changes. Our glacial simulations test the effect of a recent re-evaluation of glacial sea-ice coverage on DMS sources and sulfur aerosol deposition. Using the present-day oceanic concentrations of DMS, the model reproduces observed glacial and interglacial sulfur concentrations in the ice. This result suggests that climate change at the LGM did not greatly impact on DMS production in the oceanic sectors where sulfur aerosols deposited in central East Antarctica originate from.