Trace element chemistry of Antarctic snow as a record of past climate

This MSc research project aims to establish transfer functions between trace element chemistry (an indication of aerosol deposition) in snow pit samples and corresponding meteorological data. The relationship will be analysed for the last few decades at two coastal sites in Antarctica; Whitehall and Evans Piedmont Glaciers. Short term climate cycles (decadal, annual and seasonal) such as El Nino Southern Oscillation, Southern Annular Mode and highly variable meso-scale events in the Antarctic remain poorly understood, requiring long-term, high-resolution proxy data. By developing transfer functions between recently measured meteorological data (surface and snow temperature, snow accumulation, solar irradiance, humidity, wind velocity and direction, and barometric pressure) and snow pit geochemistry (both major cation and trace element chemistry) the relationship between aerosol-transported element abundances and their climatic depositional controls can be established. Snow samples, collected using ultra-clean techniques at Whitehall Glacier during the 2006/07 field season, and Evans Piedmont Glacier in the up coming 2007/08 season will be analysed by inductively coupled plasma mass spectrometry (ICP-MS) in the new VUW geochemistry laboratory. Dating will be constrained by characteristic annual layer counts of isotope-temperature proxies (oxygen and hydrogen) and aerosols species with a strong seasonal dependency (e.g. sea salt - Na, Sr). The effect of small scale (centimetre to metre) chemical variation resultant of sastrugi features, localised melting, temperature gradients, and differences in the ratio of wet and dry deposition of aerosols will also be determined by the comparison of multiple pits at each site. This will determine at what resolution the chemical signal of each pit is site indicative rather than pit specific.

This project is part of the New Zealand International Trans-Antarctic Scientific Expedition (NZ ITASE) programme and through a greater understanding of trace element species abundances, will be important to fully utilise long term, high resolution ice-core records in paleoclimatology.