Exploring the potential of sea salt as a proxy for sea ice extent on glacial-interglacial timescales

Sea ice is both a reflection of, and a feedback on, the Earth's climate; it is also a source of chemically-reactive trace gases that profoundly affect polar atmospheric chemistry. A record of the extent and geographical distribution of sea ice, and their co-evolution with past climate, would therefore be highly valuable, and the hope is that one or more chemical proxies measurable in polar ice cores could contribute to this. Diatom assemblages in Antarctic marine sediment cores provide robust records of when transitions between permanent sea ice, seasonal sea ice and permanent open ocean occurred at specific sites. However, it remains difficult to piece together from these the polar-wide temporal evolution of sea ice, and it is here where ice-core records, for example of sea salt, could potentially provide complementary, regionally-integrated and long-term proxies for sea-ice extent. Besides uncertainties surrounding the sources of sea salt reaching ice-core sites (e.g. the relative importance of sea-ice related sources c.f. the open ocean), the influence that the climate has on the efficiency of sea-salt transport to these sites remains uncertain. Here, we present findings from a series of idealized model experiments aimed at quantifying the relative influences of sea-salt sources and transport on the flux of sea salt to Dome C, Antarctica, with a view to ultimately assessing the potential of sea salt (and methane sulfonic acid) to infer regionally-integrated records of sea-ice extent, here and at other ice-core sites, on a range of timescales up to glacial-interglacial.