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Victoria University Antarctic Research Expedition Science and Logistics Reports 2003-04: VUWAE 48

Analyses of Snow Properties

Analyses of Snow Properties

A 4m deep snow pit was excavated to allow high resolution snow analysis. The snow profile was sampled with 1cm resolution for analysis on snow chemistry (Na, Ca, K, Mg, Cl, NO3, SO4, MS, Al, Fe, Si, Sr, Tr, Zn) and isotopic composition (δ18O and δD), dust content and mineralogy (Fig.5). The data are used to establish transfer functions between meteorological records and the snow/ice core record, for temperature, precipitation, airmass origin, wind strength and direction, storm frequency, etc. The high sampling resolution provides sub-annual resolution of the climate record. Furthermore density and temperature of the snow pack was measured with 5cm resolution (Fig.5), and snow crystal structure was investigated. This information is important to calculate annual accumulation rates and to evaluate the potential of re-crystallisation in the snow pack. Our initial results suggest excellent characteristics for ice core analysis.

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Fig.5: Analysis of snow properties including high resolution snow sampling (left), and density and temperature measurements with 5cm resolution (right).

Fig.5: Analysis of snow properties including high resolution snow sampling (left), and density and temperature measurements with 5cm resolution (right).

During our stay at Evans Piedmont Glacier two snow precipitation events occurred which provided the opportunity to sample hourly throughout the snowfall (Fig.6). This will allow us to fingerprint snow chemistry and isotopic composition with the meteorological situation as seen in the satellite image, enabling airmass trajectory reconstruction in ice core material from this site. While the first event was caused by mesoscale cyclonic activity and consisted of blowing and precipitating snow, the second event was caused by intrusion of local moist, marine airmass, leading to crystal growth at the snow surface.

Fig.6: Two snowfall events at Evans Piedmont Glacier.

Fig.6: Two snowfall events at Evans Piedmont Glacier.