Observations over recent decades have shown the Greenland Ice Sheet to be losing mass at a rapidly increasing rate. This increase in mass loss has been associated with the acceleration, thinning and retreat of many of Greenland’s large outlet glaciers – so called ‘dynamic thinning’. My interests lie in understanding the processes underlying this recent dynamic thinning, and their significance for the stability of the ice sheet in a warming climate. My PhD research focussed on subglacial hydrology as a source of short term variability in glacier velocity, while my present research examines the impact of processes occurring at the calving front, where the largest outlet glaciers make contact with the ocean.
Present: Lecturer at University of St Andrews
2016: PDRA, Universities of Edinburgh and Sheffield, “Investigating controls on flow variability in Greenland’s tidewater glaciers: the impact of runoff on fjord circulation and termini melt rates”.
2013: PhD at University of Edinburgh: “The hydrology of a land-terminating Greenlandic outlet glacier”.
Ice sheet hydrology
Melt water forms on the surface of the ice sheet during the summer months. This meltwater may flow down crevasses or moulins to reach the bed of the ice sheet, where it then drains towards the ice margin. This summer input of meltwater is associated with an increase in water pressure at the bed of the ice sheet and a consequent increase in the sliding velocity of the overlying ice. It has been suggested that this process could lead to faster ice flow and a consequent thinning of the ice sheet if the climate continued to warm and melting increased. However, great uncertainty surrounded this hypothesis, due in large part to a lack of data and a poor knowledge of what happens to the meltwater at the ice sheet bed.
We sought to address these uncertainties through a multiyear field campaign, collecting hydrology and ice velocity data from Leverett Glacier, an outlet glacier in west Greenland.
Ice-ocean interaction
The most dramatic examples of dynamic thinning have occurred at Greenland’s tidewater glaciers – outlet glaciers that terminate in the ocean. Observations have suggested that this thinning may be associated with a recent warming of subsurface waters around the coast of Greenland, but how these waters come into contact with the glaciers (which often lie at the head of lengthy fjords), and exactly how water temperature controls glacier stability, remains poorly understood.
In this research we intend to examine these issues using a combination of field data, remote sensing and numerical modelling.
Cowton, T, Sole, A, Nienow, P, Slater, D, Wilton, D & Hanna, E 2016, ‘Controls on the transport of oceanic heat to Kangerdlugssuaq Glacier, east Greenland’ Journal of Glaciology, vol In press.
Slater, DA, Nienow, PW, Goldberg, DN & Cowton, TR 2016, ‘Scalings for Submarine Melting at Tidewater Glaciers from Buoyant Plume Theory’ Journal of Physical Oceanography, vol 46, no. 6, pp. 1839-1855. DOI: 10.1175/JPO-D-15-0132.1
Cowton, T, Nienow, P, Sole, A, Bartholomew, I & Mair, D 2016, ‘Variability in ice motion at a land-terminating Greenlandic outlet glacier: the role of channelized and distributed drainage systems’ Journal of Glaciology, vol 62, no. 233, pp. 451-466. DOI: 10.1017/jog.2016.36
Hawkings, J, Wadham, J, Tranter, M, Lawson, E, Sole, A, Cowton, T, Tedstone, A, Bartholomew, I, Nienow, P, Chandler, D & Telling, J 2015, ‘The effect of warming climate on nutrient and solute export from the Greenland Ice Sheet’ Geochemical Perspectives Letters, pp. 94-104. DOI: 10.7185/geochemlet.1510
Cowton, T, D Slater, A Sole, D Goldberg, P Nienow (2015), Modeling the impact of glacial runoff on fjord circulation and submarine melt rate using a new parameterization for glacial plumes. Journal of Geophysical Research: Oceans, v. 120, p. 796-812
Slater, D, P Nienow, T Cowton, D Golderg, A Sole (2015), Effect of near terminus subglacial hydrology on tidewater glacier submarine melt rates. Geophysical Research Letters, 42(8), p2861-2868
Hawkings, J, J Wadham, M Tranter, E Lawson, A Sole, T Cowton, A Tedstone, I Bartholomew, P Nienow and D Chandler (2015), The effect of warming climate on nutrient and solute export from the Greenland Ice Sheet. Geochemical Perspectives Letters, v.1, p. 94-10
Cowton, T, P Nienow, A Sole, J Wadham, G Lis, I Bartholomew, D Mair, D Chandler (2013), Evolution of drainage system morphology at a land-terminating Greenlandic outlet glacier. Journal of Geophysical Research (Earth Surface), v. 118.
Chandler, D, J Wadham, G Lis, T Cowton, A Sole, I Bartholomew, J Telling, P Nienow, E Bagshaw, D Mair, S Vinen and A Hubbard (2013), Evolution of the subglacial drainage system beneath the Greenland Ice Sheet revealed by tracers. Nature Geoscience.
