Date of Award

2011

Level of Access Assigned by Author

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Earth Sciences

Advisor

Paul A. Mayewski

Second Committee Member

Karl Kreutz

Third Committee Member

Gordon Hamilton

Abstract

The first section of this study presents major ion, trace element, heavy metal, rare earth element and oxygen isotope data from a series of surface snow samples and shallow firn sections collected along four US ITASE traverses across extensive regions of East and West Antarctica. In each sample the dissolved major ion, total trace element, and d18O concentrations are measured. This provides a baseline from which changes in the chemistry of the atmosphere over Antarctica can be monitored under expected warming scenarios and continued intensification of industrial activities in the Southern Hemisphere. Satellite remote sensing measurements of microwave backscatter and grain size assist in the identification of glaze/dune areas across Antarctica and show how chemical concentrations are higher in these areas, precluding them from containing useful high-resolution chemical climate records. The majority of the non-glaze/dune samples in this study exhibit similar, or lower, concentrations to those from previous studies. Consequently, the results presented here comprise a conservative baseline for Antarctic surface snow chemical concentrations. The second section of this study presents a 200-year proxy for Northerly Air Mass Incursions (NAMI) into central and western West Antarctica. The NAMI proxy is developed from the examination of 19 shallow (21m – 150m deep) Antarctic ice core non-sea-salt (nss) Ca2+ concentration records and it exhibits a significant rise in recent decades. This rise is unprecedented for at least the last 200 years and is coincident with anthropogenically-driven changes in other large-scale Southern Hemisphere (SH) environmental phenomena such as greenhouse gas induced warming, ozone depletion and the associated intensification of the SH westerlies. Statistical analysis suggests that atmospheric circulation is the dominant factor affecting nssCa2+ concentrations throughout central and western West Antarctica.

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