Variations in snow and firn chemistry along US ITASE traverses and the effect of surface glazing

Abstract

This study 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. It is the first study to measure more than 25 chemical constituents in the surface snow and firn across extensive regions of Antarctica. We present 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 East and West Antarctica. In each sample we measure dissolved concentrations of Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl^&minus;, NO₃⁺, SO₄^2&minus;, and MS^&minus; using ion chromatography and total concentrations of Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Al, S, Ca, Ti, V, Cr, Mn, Fe, Co, Na, Mg, Li, and K using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). We also measure &delta;¹⁸O by isotope ratio mass spectrometry. <br><br> Satellite remote sensing measurements of microwave backscatter and grain size are used to assist in the identification of glaze/dune areas across Antarctica and determine if these areas can possibly contain useful 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. <br><br> The elements Cd, Pb, As and Bi are enriched across Antarctica relative to both ocean and upper crust elemental ratios. Local and global volcanic outgassing may account for the majority of the Bi measured in East and West Antarctica and for a significant fraction of the Cd and As. However, significant concentrations of Cd, Pb, and As remain across much of Antarctica

Spatial–temporal dynamics of chemical composition of surface snow in East Antarctica along the Progress station–Vostok station transect

“…almost exponential decrease with inland distance and altitude. Similar trends were noted for the majority of coast to inland traverses (Kreutz and Mayewsky, 1999;Bertler et al, 2005;Kärkäs et al, 2005;Dixon et al, 2013). It should be noted that, unlike Na, Mg shows decreasing trend only at the beginning of the traverse (between 55 and 519 km or from 1200 to 3100 m a.s.l.).…”

“…The Antarctic surface snow chemistry was previously studied along the traverses from coast to inland (Legrand and Delmas, 1985;Kreutz and Mayewsky, 1999;Bertler et al, 2005;Kärkäs et al, 2005;Dixon et al, 2013). In particular, concentrations of dissolved snow components (major ions) were studied versus such physical parameters as distance, elevation and accumulation rate along the traverses (Cincinelli et al, 2001;Udisti et al, 2004;Bertler et al, 2005).…”

Determinação de elementos-traço em testemunho de firn antártico usando ICP-MS

“…Para calcular a contribuição do spray marinho foi utilizado o fator de enriquecimento oceânico (FE o ), calculado a partir da seguinte equação, segundo Dixon et al (2013): O sódio foi escolhido como elemento de referência por ser o principal constituinte do sal marinho (Weller et al 2008, Dixon et al 2013. Neste trabalho, as razões de concentrações elementares de referência correspondem à composição média da água oceânica (Lide 2005).…”

“…Para separar essas duas fontes potenciais, foram calculadas a fração marinha e crustal de cada elemento de acordo com a seguinte fórmula (Dixon et al 2013 A fração oceânica foi subtraída de cada amostra e então foi calculada a fração crustal utilizando a mesma fórmula, porém substituindo sódio por manganês como material de referência.…”

Non-climatic signal in ice core records: lessons from Antarctic megadunes

“…The first reports on the existence of the huge waves on the surface of the Antarctic ice sheet were made soon after the beginning of the extensive exploration of the Antarctic interior during the International Geophysical Year (IGY) (Dolgushin, 1958).…”