Resolving subglacial properties, hydrological networks and dynamic evolution of ice flow on the Greenland Ice Sheet (RESPONDER)
Funding: European Research Council (Lead PI: P. Christoffersen, U. Cambridge)
€824,645 to Aberystwyth U. (2016-2021)
RESPONDER will begin in late 2016 and my direct responsibility involves drilling and instrumenting boreholes to depths of ~1,200 m on Store Glacier, Greenland.
The Greenland Ice Sheet is losing mass at a growing rate and has since 2010 caused sea level rise of 1 mm/year. The most severe changes occur in the drainage basins of marine-terminating glaciers, which flow rapidly and drain 88% of the ice sheet. The latest report by the Intergovernmental Panel on Climate Change concluded that the widespread acceleration of these glaciers in recent years was a response to interaction with the ocean and unrelated to basal lubrication of ice flow; yet, observations have since shown that many of these glaciers respond to the growing volume of surface meltwater, which reaches the bed when surface lakes drain. This basal lubrication mechanism is unknown, but exhibits contrasting control on ice flow at the coast and in the interior where surface melting increasingly forms lakes. This lack of knowledge is a major source of uncertainty in the current generation of ice sheet models used to predict sea level change.
The fundamental goal of RESPONDER is to understand how hydrological networks at the base of the Greenland Ice Sheet evolve over seasons and over multiple years, and how this evolution impacts on ice flow in the interior and at the coast. The project has the following aims:
AIM 1 is to identify glaciological ‘hotspots’ and sites for subglacial access drilling and borehole exploration by tracking hydrological pathways beneath Store Glacier, a large marine-terminating glacier in Uummannaq Fjord, using novel geophysical imaging techniques and unmanned aerial vehicles (UAVs).
AIM 2 is to observe and quantify the hydrological networks of Store Glacier while measuring basal slip and strain within ice with probes and sensors installed in boreholes drilled at ‘coastal’ and ‘interior’ targets.
AIM 3 is to predict the co-evolution of ice flow and hydrological networks in the Store Glacier drainage basin, and assess the vulnerability of the Greenland Ice Sheet as a whole, by integrating field observations in state-of-the-art ice sheet models.
Impact of surface melt and ponding on ice-shelf dynamics and stability (MIDAS)
Funding: Natural Environment Research Council (NE/L006707/1) (with A Luckman, B. Kulessa and I Rutt, Swansea U.)
£302,744 to Aberystwyth U. (2014-2017)
MIDAS fieldwork has now come to completion with a second fieldseason in October - December 2015. This provided a substantial quantity of empirical data from a series of boreholes drilled along two flow-line transects on the ice shelf. These are to be combined with radar, seismic and remote sensing data over the next couple of years.
Ice shelves fringe around half of the Antarctic coastline and exert a fundamental control on the discharge of ice from the Antarctic ice sheets. They can gain and lose mass through interactions with both the ocean and the atmosphere. In the long term their evolution and impact on the ice sheets is controlled by the ocean, but the effect of a warming atmosphere may dominate in the shorter term by providing the conditions and mechanisms for abrupt ice shelf collapse. The atmosphere on the Antarctic Peninsula, where ice shelves have recently undergone most change, is warming faster than anywhere else on Earth. Atmospheric warming leading to surface melt and ponding has already been implicated in the collapse of ice shelves of the Antarctic Peninsula - the loss of the Larsen B ice shelf in 2002 led to significant and ongoing glacier acceleration, drawdown of grounded ice from the interior, and contribution to sea level rise. There is no doubt that climate warming will lead to more ice shelves being subject to temperatures above freezing for significant periods. The much larger southerly neighbour of the Larsen B ice shelf, Larsen C, annually experiences periods of surface melt and ponding, and appears in parts to be approaching the level of firn densification that preceded the Larsen B collapse. Very little is known, however, about the spatial and temporal pattern of melt and firn densification, the distribution and size of ponds, or the impact of these factors on flow and fracture. A key control on ice sheet mass balance is therefore inadequately understood.
Our project will address this issue through a combined program of fieldwork, remote sensing and numerical modelling. We will focus on the Larsen C Ice Shelf as an ideal example of a large ice shelf experiencing a wide variety of surface melt and ponding conditions, and which is readily accessible for field measurements. Using borehole camera survey and monitoring instrumentation, and surface geophysics, we will acquire much needed new data about the density and temperature across the ice shelf in the upper half of the ice column. We will probe layers of ice going back hundreds of years to understand the history of melt and ponding on Larsen C Ice Shelf. To understand the impact on the ice shelf of past and future melt and ponding, we will develop a coupled simulation which will use a regional climate model to predict surface melt and ponding and an ice shelf numerical model to test the impact of this meltwater on flow and fracture. These models will be optimised by data from fieldwork and remote sensing that we will collect. The outcome will be the most accurate model of an ice shelf to date which will allow us fully understand impact of melt and ponding on ice shelves and to predict the future evolution of Larsen C Ice Shelf over the next century.
3-D ice-mass access and mapping facility (3-D Ice)
Funding: Higher Education Funding Council for Wales: Research Capital Funding
£145,450 to Aberystwyth U. (2013-2015)
This support has allowed the construction of a hot water drill with a depth capacity of ~1 km, to be used in Greenland for SAFIRE (below) and further adapted for RESPONDER (above)
Subglacial Access and Fast Ice Research Experiment (SAFIRE)
Funding: Natural Environment Research Council (NE/K006126/1) (with A Hubbard, Aberystwyth U. and P Christoffrsen, U. Cambridge)
£426,090 to Aberystwyth U. (2013-2016)
SAFIRE continues into its second full field season in summer 2016, when we will once again be drilling boreholes to the bed of Store Glacier - this time to focus on sampling subglacial sediment, obtaining optical televiewer borehole logs, and installing new fibreoptic borehole strings alongside traditional wired sensors. Season 1, completed in summer 2014, was a great success resulting in four boreholes to the bed of the glacier and the installation of various englacial and subglacial sensors.
Marine-terminating outlet glaciers drain 88% of the Greenland Ice Sheet and are responsible for at least half of the ice sheet's net annual mass loss, which at present is around 200 km3/year. Understanding the processes that drive the fast flow of these glaciers is crucial because a growing body of evidence points to a strong, but spatially varied and often complex, response to both oceanographic and atmospheric forcing. While the bed of glaciers elsewhere is known to strongly influence the flow of ice, no observations have ever been made from beneath a marine-terminating glacier in Greenland; a potential and likely cause of significant error in current predictions of sea level rise. This project will correct this paucity of observational constraint by gaining access to the bed of a major marine-terminating outlet glacier (Store Gletscher) in West Greenland, in order to observe and characterise the basal interface. With instruments deployed at the bed and on the glacier's surface and forefield, the project will fully resolve the basal control on ice flow and the glacier's response to iceberg calving, including the effects of meltwater input to the bed. The observational outcome will inform the glacier's sensitivity to atmospheric as well as oceanographic forcing while also enabling numerical ice flow modelling of unprecedented detail and accuracy.
Constraining ice-mass changes in coastal Dronning Maud Land, Antarctica (IceCon)
Funding: Belgian Science Policy Office (Lead PI: F. Pattyn, UL Brussels)
€970,395 total grant (2012-2016)
Extended-range optical televiewer imaging of the NEEM deep ice borehole, Greenland
Funding: Natural Environment Research Council (NE/J013544/1)
£65,509 to Aberystwyth U. (2012-2013)
Character and formation of meteoric and marine ice facies: Roi Baudouin Ice Shelf, Antarctica
Funding: Natural Environment Research Council Isotope Geosciences Facilities (IP-1244-0511)
£17,500 in kind to Aberystwyth U. (2011-2012)
Digital optical televiewing of the North Greenland Eemian (NEEM) Ice Drilling Project test borehole
Funding: Royal Society
£10,740 to Aberystwyth U. (2008-2010)
Ice and Climate Exploration Facility
Funding: Aberystwyth University: Capital Investment Strategy
£280,000 to BH (2008-2013)
Global Change Research Facility: Ice coring and physical analysis
Funding: HEFCW Science Research Investment Fund II
£122,681 to Aberystwyth U. (2005-2006)
Quantification of the relationships between glacier recession, water-levels in moraine-dammed lakes, and dam-wall erosion: Rio Santa, Cordillera Blanca, Peru
Funding: University of Wales, Aberystwyth Research Fund (AB22/716)
£6,135 to BH (2004-2005)
Effect of the spatial variability of physical parameters on the rheology of temperate glaciers and their modelled response to climate change
Funding: Natural Environment Research Council (NER/A/S/2002/00607) (with T. Murray & J. West, U. Leeds and H. Mader, U. Bristol)
£187,734 total grant (2004-2007)
Direct measurement of basal sliding at temperate glaciers
Funding: University of Wales Aberystwyth Research Fund
£1,844 to BH (2000-2001)
Geotechnical centrifuge modelling of ice rheology
Funding: University of Wales Academic Support Fund (with Brice R. Rea & John McKinley, UW Cardiff)
£9,210 total grant (1999-2000)
Three-dimensional patterns of velocity and stress in glaciers
Funding: Natural Environment Research Council (GR3/11216) (with I. Willis , U. Cambridge and P. Nienow, U. Glasgow)
£102,679 total grant (1998-2000)
Laboratory-based investigations of the hydraulic conductivity of deforming subglacial sediments
Funding: University of Wales Research Fund (with A. Maltman and D. McCarroll)
Quantitative characterisation of the roughness of glacier beds
Funding: University of Wales Collaboration Fund (with M. Siegert and D. McCarroll, UW Swansea)
Basal ice character and rheology: Taylor Glacier, Antarctica
Funding: The Royal Society
Geophysical investigations of the presence and character of englacial meltwater drainage pathways
Funding: U.K. Natural Environmental Research Council (GR9/2530) (with A. Binley, U. Lancaster)
The formation of clear facies basal ice at Alpine glaciers: implications for subglacial water chemistry
Funding: U.K. Natural Environment Research Council (GR9/2026)
Regelation and the precipitation of subglacial calcite crusts
Funding: Nuffield Foundation
Investigations of subglacial sediment eluviation at Alpine glaciers
Funding: University of Wales, Aberystwyth