Spatial and temporal variability in summer snow pack in Dronning Maud Land, Antarctica

T Vihma,O.-P Mattila,R Pirazzini,M M Johansson

doi:10.5194/tc-5-187-2011

T Vihma, O.-P Mattila + Show 2 more

Open Access

https://doi.org/10.5194/tc-5-187-2011

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Abstract

Abstract. To quantify the spatial and temporal variability in the snow pack, field measurements were carried out during four summers in Dronning Maud Land, Antarctica. Data from a 310-km-long transect revealed the largest horizontal gradients in snow density, temperature, and hardness in the escarpment region. On the local scale, day-to-day temporal variability dominated the standard deviation of snow temperature, while the diurnal cycle was of second significance, and horizontal variability on the scale of 0.4 to 10 m was least important. In the uppermost 0.2 m, the snow temperature was correlated with the air temperature over the previous 6–12 h, whereas at the depths of 0.3 to 0.5 m the most important time scale was 3 days. Cloud cover and radiative fluxes affected the snow temperature in the uppermost 0.30 m and the snow density in the uppermost 0.10 m. Both on the intra-pit and transect scales, the ratio of horizontal to temporal variability increased with depth. The horizontal standard deviation of snow density increased rapidly between the scales of 0.4 and 2 m, and more gradually from 10 to 100 m. Inter-annual variations in snow temperature and density were due to inter-annual differences in air temperature and the timing of the precipitation events.

Highlights

Horizontal heterogeneity in the snow pack is primarily introduced by the underlying topography, which influences the distribution of accumulation, and by the prevailing meteorological conditions, through mechanical stress by wind and melting due to radiation and air-snow heat flux (Colbeck, 1991; Rotschky et al, 2007)
Day-to-day temporal variability dominated the standard deviation of snow temperature, while the diurnal cycle was of second significance, and horizontal variability on the scale of 0.4 to 10 m was least important
Horizontal heterogeneity in the snow pack is primarily introduced by the underlying topography, which influences the distribution of accumulation, and by the prevailing meteorological conditions, through mechanical stress by wind and melting due to radiation and air-snow heat flux (Colbeck, 1991; Rotschky et al, 2007)

Summary

Introduction

Horizontal heterogeneity in the snow pack is primarily introduced by the underlying topography, which influences the distribution of accumulation, and by the prevailing meteorological conditions, through mechanical stress by wind and melting due to radiation and air-snow heat flux (Colbeck, 1991; Rotschky et al, 2007). Even slight topographic variations interacting with the weather often generate horizontal heterogeneity (Frezzotti et al, 2002a, b). Synoptic-scale variations in weather generate heterogeneity in the snow pack at scales of tens to hundreds of kilometres but, according to Sturm and Benson (2004), the heterogeneity often approaches a peak value at a scale of 100 m, related to wind-drift structures of approximately this size. Layers formed during windy conditions are likely to be more spatially variable than other layers (Kronholm et al, 2004)

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