Summary
Law Dome, in coastal East Antarctica, is a relatively low-latitude site (6646S) with a strong maritime climate, dominated by cyclonic precipitation which produces high snow accumulation rates and very well-resolved ice core records. These records exhibit strong maritime influence with links to climate at mid-latitudes. The annual accumulation record has a strong correlation (r>0.6) with sea-level pressure across Southern Australia. Here we present a new technique for partitioning the annual accumulation signal into nominal summer and winter series. The summer component is identified with the accumulation in which the sulphate/chloride ratio exceeds that in sea-water; the remaining portion of the year, during which sea-salt dominates the sulphate budget, is the nominal winter component. Sulphate from sporadic volcanic input can be excluded or treated separately. This marker is found to exhibit a sharp transition that gives a reliable identification of onset and termination of biogenic summer sulphate input. The winter accumulation, defined in this way, comprises ~54% of annual accumulation over the last century but exhibits higher variability than summer accumulation. We explore the interpretation and calibration of this new proxy and investigate the connections with mid-latitude meteorology