Reconstruction of Antarctic Climate Change Using Ice Core Proxy Records from the Coastal Dronning Maud Land, East Antarctica

Abstract

Antarctic ice core records have provided unprecedented information on past climatic changes and forcing factors on decadal to millennial timescales. The glaciochemical and stable isotope records of a shallow ice core from the coastal Dronning Maud Land (East Antarctica) were used here to reconstruct the coastal Antarctic environmental variability during the past ~470 years. Sea salt ion data indicate a significant additional contribution of chloride ions compared to sea water values, possibly through atmospheric scavenging. The nitrate (NO 3 -) profile exhibit significant temporal shifts than that of the sulphate (SO 4 2-), with a major shift around 1750 AD. The changes in NO 3 record are synchronous with the proxy record of solar activity ( 10 Be profile from a South Pole ice core), suggesting enhanced NO 3 values during periods of reduced solar activity like the Dalton Minimum (~1790-1830 AD) and Maunder Minimum (~1640-1710 AD). The G 18 O records reveal that the more negative G 18 O values were coeval with several events of increased NO 3 concentrations, suggesting enhanced preservation of NO 3 during periods of reduced air temperatures. The G 18 O and GD records of the core also suggest significant short-term and long-tem variability with more negative values indicating relatively lower air temperatures prior to 1715 AD. The G 18 O records also revealed a significant warming of 2.7°C for the past 470 years, with a warming of ~0.6°C per century.

Past, Present and Future Climate of Antarctica

“…The spatial variability of marine phytoplankton sourced methane sulphonic acid ranges from 3 to ~160 ppb. With the exception of some coastal pockets, the highest concentration of methane sulphonic acid occurs at coastal sites, which decreases inland with distance, altitude of the site and influenced by seasonal atmospheric circulation pattern [30]. Terrestrial and marine based Ca ++ , Mg ++ , and K + concentrations range from 0.1 to 740 ppb, from 0.2 to ~2000 ppb, and from 0.1 to 600 ppb, respectively [29].…”