Mass budgets of the Lambert, Mellor and Fisher Glaciers and basal fluxes beneath their flowbands on Amery Ice Shelf

Abstract

respectively. We find a much larger total basal melting and net melting than the results for the whole Amery Ice Shelf derived from previous modeling and oceanographic measurements.

Analysis of velocity field, mass balance, and basal melt of the Lambert Glacier–Amery Ice Shelf system by incorporating Radarsat SAR interferometry and ICESat laser altimetry measurements

“…Since the airborne RES signals may not penetrate a basal marine ice layer [ Fricker et al , 2001], we also estimated the ice thickness for the floating ice shelf based on a hydrostatic equilibrium model [ Fricker et al , 2001; Joughin and Padman , 2003] applied to the ICESat laser altimetry data. In our hydrostatic calculation, the column‐averaged ice density value varies from the ice shelf front to the grounding zone in the range of 890.5–921.0 kg m −3 as in the work of Wen et al [2007]. The comparison of the hydrostatic ice thickness estimates with airborne RES ice thickness measurements confirms the existence of an extensive marine ice layer in the downstream section of the ice shelf as reported by Fricker et al [2001], Wang et al [2006], Wen et al [2007], Craven et al [2009], and Wen et al [2010].…”

“…In our hydrostatic calculation, the column‐averaged ice density value varies from the ice shelf front to the grounding zone in the range of 890.5–921.0 kg m −3 as in the work of Wen et al [2007]. The comparison of the hydrostatic ice thickness estimates with airborne RES ice thickness measurements confirms the existence of an extensive marine ice layer in the downstream section of the ice shelf as reported by Fricker et al [2001], Wang et al [2006], Wen et al [2007], Craven et al [2009], and Wen et al [2010]. The RES ice thickness measurements are used for the fluxgates located in the grounding zone, where we found that hydrostatically derived ice thickness values were not reliable, apparently because the hydrostatic equilibrium condition was not satisfied.…”

“…In a similar fashion to Fricker et al [2002a], Rignot [2002], Rignot et al [2002], Wen et al [2007], and Wen et al [2010], we also placed fluxgates in the Amery Ice Shelf to estimate basal melting (or accretion) beneath the ice shelf (Figure 3). While Wen et al [2007] concentrated on a detailed study of the basal mass budget along the Fisher, Mellor, and Lambert flow bands, the three cascading gates used here simply give broad area coverage of the whole ice shelf. The width of the Amery Ice Shelf increases from about 40 km at the southern end to about 200 km at the front.…”

“…They also observed mass balance variations between drainage sectors with the more northerly sectors tending toward a slightly negative mass balance. Wen et al [2007] studied the Mellor, Fisher, and Lambert glaciers and estimated the overall mass budget was near to balance (−2.6 ± 6.5 Gt a −1 ). Wen et al [2008] extended their analysis to include the entire region of grounded ice flowing into the Amery Ice Shelf.…”

“…Previous studies of the mass balance of the Lambert–Amery system mainly focused on the three fast‐moving southern tributary glacial systems, either separately [ Wen et al , 2007] or as a whole [ Allison , 1979; Fricker et al , 2000b; Rignot , 2002; Rignot and Thomas , 2002; Bentley and Giovinetto , 1991]. Wen et al [2008] studied ice flow from the eastern and western sectors into the Amery Ice shelf and reported aggregated mass budgets.…”