High basal melting forming a channel at the grounding line of Ross Ice Shelf, Antarctica

作者：Marsh Oliver J^*; Fricker Helen A; Siegfried Matthew R; Christianson Knut; Nicholls Keith W; Corr Hugh F J; Catania Ginny

来源：Geophysical Research Letters, 2016, 43(1): 250-255.

DOI：10.1002/2015GL066612

• ice shelf channels
• phase-sensitive radar
• Whillans Ice Stream

Antarctica's ice shelves are thinning at an increasing rate, affecting their buttressing ability. Channels in the ice shelf base unevenly distribute melting, and their evolution provides insight into changing subglacial and oceanic conditions. Here we used phase-sensitive radar measurements to estimate basal melt rates in a channel beneath the currently stable Ross Ice Shelf. Melt rates of 22.20.2ma(-1) (>2500% the overall background rate) were observed 1.7km seaward of Mercer/Whillans Ice Stream grounding line, close to where subglacial water discharge is expected. Laser altimetry shows a corresponding, steadily deepening surface channel. Two relict channels to the north suggest recent subglacial drainage reorganization beneath Whillans Ice Stream approximately coincident with the shutdown of Kamb Ice Stream. This rapid channel formation implies that shifts in subglacial hydrology may impact ice shelf stability.

• 出版日期2016-1-16