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SPRI Review 1999: Glacier Hydrology Group

Glacier Hydrology Group

Dr N. Arnold

Dr G. de Q. Robin, Dr I. Willis (Department of Geography),
Dr D. Mair (Department of Geography), D. Rippin, A. Fox

The Glacier Hydrology Group has continued to expand its activities in high Arctic environments. This year, the second six-week field trip linked with the NERC-funded PhD studentship held by D. Rippin (supervised by Drs Neil Arnold and I. Willis) took place in Ny-Ålesund, Svalbard. Dr Arnold and Rippin were accompanied by two undergraduate students from the Department of Geography, who, as well as acting as field assistants, were carrying out work for their undergraduate dissertations. The main focus of Rippin's work continued to be detailed, spatially extensive surveys of the motion of Midre Lovenbreen, a polythermal valley glacier. This research aims to evaluate intra-annual and inter-annual motion patterns on a high Arctic glacier that could be linked to seasonal changes in the glacier hydrological system. This work is linked to theoretical reconstructions of the possible subglacial hydrological system, using digital elevation models of the glacier surface and bed surface to define subglacial hydraulic potentials, which are believed to govern the flow of subglacial water. This year also saw an intensive ground-based radio-echo survey of the glacier, following a successful application for equipment from the NERC Geophysical Equipment Pool. These radio-echo surveys aimed to evaluate the spatial extent of ice at, or below, the pressure melting point, and if any temporal variation in the extent of the temperate area occurred during a summer. These data are currently being processed, but initial results seem very promising.

The ongoing collaborative work with Dr A.J. Hodson of Sheffield University on Midre Lovenbreen continues. Three years' worth of hourly meteorological data have now been collected, and these data are being analysed for both temporal and spatial patterns within the glacier surface energy balance.

Following a successful application for a NERC Small Grant, Dr Arnold also carried out fieldwork on Midre Lovenbreen for a new project to evaluate spatial and temporal variability in glacier surface characteristics, especially snow depth, albedo, and surface roughness. These are all important controls on glacier mass balance, and the project aims to investigate small-scale variability in these parameters, in order more effectively to model the spatial variability of surface properties in distributed mass-balance models, such as the one that has already been developed by the group. Dr Gareth Rees is also involved in this project, as it aims to use remotely sensed data, both visible and SAR, to evaluate spatial variations in these surface characteristics at a glacier-wide scale. A second, late-winter trip associated with this project will be made next in April next year by Drs Arnold and Rees.

Dr Arnold made a second trip during the summer, to present the work he has been involved with for the Stage Three Project, an international, interdisciplinary group based in the Department of Earth Sciences, Cambridge. The project aims to reconstruct the climate of Europe during Oxygen Isotope Stage 3, a warmer period during the last glacial period, around 40,000 years ago. Dr Arnold's input was a modelling-based study of the possible extent of the Scandinavian Ice Sheet at this time, for use as a boundary condition in a global climate model. The intensive climate modelling phase, by Dr Eric Barron and his research group at Pennsylvania State University, is now underway. These initial results were presented by Dr Arnold at the XVth International Quaternary Association Congress in Durban, South Africa, in August, less than a week after Dr Arnold's return from the Arctic. The ice-sheet modelling results are also being linked with a comprehensive Earth model, developed by Professor Kurt Lambeck of the Australian National University, to reconstruct patterns of isostatic adjustment in Europe during the last glacial period. Dr Arnold is also working with Dr David Pollard of Penn State to develop the ice-sheet model from two-dimensional to three-dimensional.

Andy Fox joined the group in October, on a NERC-funded PhD studentship, held jointly between Drs Arnold and Willis, in the Department of Geography. Fox has just completed a Master's degree at the University of Colorado, Boulder, on snow hydrology, and his research aims to develop this work into a distributed, physically based model of snow hydrology, which can be used in conjunction with the group's existing energy-balance model to calculate the delivery of surface melt during the course of a melt-season to the en- and sub-glacial hydrological system. Fox will undertake field work in association with this project, initially at Haut Glacier d'Arolla, in the Swiss Alps, but subsequently in the Arctic, where snow conditions are quite different, due to the lower precipitation rates and lower winter temperatures.

The extensive SPRI archive of airborne radio-echo transects of Antarctica has been used intensively by Dr Gordon Robin, in ongoing investigations of Lake Vostok beneath the Antarctic Ice Sheet. This work has been carried out in collaboration with Dr Martin Seigert, at the University of Bristol. The discovery of this lake, the largest beneath the Antarctic Ice Sheet, and believed to have been isolated by the overlying ice sheet for several million years, has provoked intense scientific and public interest. The Institute is in discussions with the BBC, concerning the making of a film about these discoveries.