The Age Structure of the Greenland ice sheet from Airborne Radar Data (ASGARD)

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Recent observations suggest that the Greenland Ice Sheet, is losing ice at an accelerating rate. Because the ice sheet contains 2.85 million cubic km, equivalent to a global sea level rise of 7.2 m, this melting could contribute substantially to future sea level rise. Despite this, current sea level projections specifically exclude changes in the ice flow of the Greenland ice sheet. This is because of difficulties in knowing whether projected changes in the ice sheet are being correctly modelled. Improving the ability to be able to model ice flow dynamics in Greenland is an urgent problem.To quantify the potential threat that Greenland poses to longer-term global sea-level rise we need a more profound understanding of the internal ice sheet structure. This will help inform how the ice sheet may responses to changing climate. Airborne geophysics provides a means to observe the internal structure of the Greenland ice sheet. Previously, technical difficulties in extracting information, have prevented the use of existing aerogeophysical data. Here, it is proposed to apply new means to overcome these difficulties. The new methods are based on using techniques which have been developed in other research fields. They will be applied here to this new ice sheet aerogeophysical problem, thereby helping to make the best use of pre-existing expensive aerogeophyscial observations. The new methods will describe quantitatively the internal ages of the ice sheet. The new age information extracted will allow glaciologists to test, at the continental-scale, whether models of ice flow are correct. This will help to provide a better understanding of ongoing Greenland ice sheet changes, helping to understand the past and predict the future. This is a necessary step in reducing uncertainties on Greenland mass loss predictions.