Australia: The Land Where Time Began

A biography of the Australian continent 

Antarctica - Persistent Wind Scour influence on Surface Mass Balance

According to the authors¹ a key constraint for estimates of mass balance in Antarctica is accurate quantification of the accumulation of surface snow on the continent, as well as for climatic interpretations of ice core records (Frezzotti et al., 2005; Arthern, Winebrenner and Vaughn, 2006). Snow is eroded and sublimated over Antarctica by near-surface winds that accelerate down the surface slopes that are relatively steep. Many localised regions, of  ≤ 200 sq km, with reduced surface accumulation (Scambos et al., 2012; Frezzotti et al., 2004; Scarchilli et al., 2010; Siegert, Hindmarsh & Hamilton, Jiahong, et al., 2006), result from this scour. Sparse point measurements or coarse atmospheric models that don't capture these local processes, and overestimate the net mass input in the wind-scour zones (Scambos et al., 2012) are the basis for estimates of surface mass balance in Antarctica. In this study the authors¹ combined airborne radar observations of stratigraphic layers, that are unconformable, with lidar-derived measurements of surface roughness to identify extensive wind-scour zones over Dome A, in the East Antarctica interior. As bedrock topography controls the scour zones they are persistent. The authors¹ developed an empirical model to predict the locations of wind-scour zones throughout Antarctica, based on their Dome A observations, their results indicate that East Antarctica contains most of the these zones. The authors¹ have estimated that of the surface area of Antarctica about 2.7-6.6  % has negative net accumulation that is persistent as a result of wind scour, and this suggests that the snow mass input across the continent is overestimated by 11-36.5 Gt/year in mass balance calculations at the present.

Sources & Further reading

1. Das, Indrani, Robin E. Bell, Ted A. Scambos, Michael Wolovick, Timothy T. Creyts, Michael Studinger, Nicholas Frearson, et al. "Influence of Persistent Wind Scour on the Surface Mass Balance of Antarctica." Nature Geosci 6, no. 5 (05//print 2013): 367-71.