Research Fellows Directory
Gwendolyn Leysinger Vieli
Dr Gwendolyn Leysinger Vieli
University of Durham
The Antarctic ice-sheet has traditionally been seen as almost inert, responding to the climate only very slowly. However, recent surveys of the ice-sheet surface from space show that the Antarctic ice-sheet, and the water system (hydrology) beneath it, is far more dynamic than previously thought.
It has been speculated that subglacial water discharge events may explain changes in the ice sheets internal structure, seen as layers in radio-echo-sounding (RES) data from Antarctica. Radar sends pulses of energy of a certain wavelength through the ice-sheet that are reflected back to the surface by layers of unusual electric properties. These radar profiles show vertically distributed reflecting layers within the ice-sheet, which were deposited at the same time (isochrones). Such RES layers provide information about the history of ice-sheet flow and conditions at the bed. Radar layers are the only way to obtain information about past ice-flow in a locality without drilling into the ice. Information from internal radar layers has never previously been used to explore time-dependent changes in subglacial hydrology (meltwater) and other subglacial conditions.
The aim of this project is to understand the influence of changes in ice flow and subglacial processes, in particular major subglacial melt or drainage events, upon englacial layer structure in the Antarctic ice-sheet, as observed in RES data and thereby quantify former basal processes. To this aim, englacial layer architecture will be simulated using numerical modelling and then compared with observed internal layers over regions where changing subglacial conditions are known to occur.
Although ice dynamics has been recognised to be crucial for the ice loss from Antarctica (e.g. IPCC report 2007), there is still a lack of understanding of the role of subglacial melt, freeze-on and drainage on the flow of ice-sheets. The findings from this project will provide an important step towards understanding ice-sheet dynamics.