Spatial and temporal variability of surface mass balance near Talos Dome, East Antarctica

Abstract

[1] Predictions concerning Antarctica's contribution to sea level change have been hampered by poor knowledge of surface mass balance. Snow accumulation is the most direct climate indicator and has important implications for paleoclimatic reconstruction from ice cores. Snow accumulation measurements (stake, core, snow radar) taken along a 500-km transect crossing Talos in plateau areas and up to 260 kg m À2 yr À1 in slope areas and account for 20-75% of precipitation, whereas depositional features are negligible in surface mass balance.

Spatial and temporal variability of snow chemical composition and accumulation rate at Talos Dome site (East Antarctica)

“…In this work, we find a statistically significant agreement among the calculated accumulation rates (see later). The slight differences actually appear to follow the pattern observed by Frezzotti et al (2007), with accumulation rate in SSW sector (SP2 and SP3 points or West and South point: 92 and 81 mm w.e. year −1 respectively) higher than those in NNE sector (SP1 and SP4 or North and East points: 70 and 74 mm w.e.…”

“…At TD, wind blows uphill from the SW with a gradient of 1-2 m km −1 for a distance of 100 km. As pointed out by Frezzotti et al (2007), the higher accumulation in the SSW sector can be correlated with reduced winddriven sublimation in this area, which is due to the positive slope gradient that reduces wind velocities. In this work, we find a statistically significant agreement among the calculated accumulation rates (see later).…”

“…Our results show indeed that such redistribution processes are not able to mix summer and winter layers because of a clear seasonal signal is observed and used for stratigraphic dating. Previous studies on the same site, Frezzotti et al (2004Frezzotti et al ( , 2007 reported that accumulation decreases downwind of TD (N-NE) and is higher in the SSW sector. TD surface contour lines are elliptical and elongated in a NW-SE direction; the NW and NE slopes are steeper.…”

“…Stake measurements and sastrugi heights suggest that the annual local noise in snow accumulation can be ±30 mm w.e., which constitutes about 35% of the average annual accumulation (Stenni et al, 2002). Previous work by Frezzotti et al (2007) shows that the largest irregularity in snow morphology occurs in early summer whereas the minimum is recorded in late summer thus limiting the layering disturbance only to the summer season. In this way, annual signal can still be identified.…”

Observations: Cryosphere

“…They also demonstrate a good correlation exists between temporal variations in SMB and solar activity on the scale of the 200-year de Vries cycle. Beyond these studies, the preparation of the required full mass balance budget for an ice sheet requires accounting for Dynamic Ice Loss (DIL) as well as SMB; DIL, which represents the breakup and melting of the terminus of peripheral or valley outlet glaciers, is a difficult number to estimate accurately (Magand et al 2007;Frezzotti et al, 2007). Boening et al (2012) point out "an improved understanding of processes dominating the sensitive balance between mass loss primarily due to glacial discharge and mass gain through precipitation is essential for determining the future behavior of the Antarctic ice sheet and its contribution to sea level rise."…”