Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Key observations related to the evolution of the basal environment of a large ice stream  (KOEBELI)

Outline
The Greenland ice sheet is expected to change rapidly under warmer climate conditions. The evolution of total mass balance is closely linked to the evolution of the outlet ice streams. These ice streams transport ice from the interior ice sheet to the ocean at very high flow velocities. The highest mass fluxes and flow velocities are reached in Jakobshavn Isbrae which drains about 6.5 % of the Greenland ice sheet. Jakobshavn Isbrae retreated dramatically since 1998, while the flow velocity increased from 7 km/a to about 12 km/a. One likely explanation is that the calving front retreated behind pinning points at the bed or on the fjord walls. Some measurements also indicate changes in the mode of flow as far as 50 km inland. If the ice stream accelerated because of faster motion over the bedrock is a matter of debate. Our main goal is to measure water pressure at the glacier base, and ice deformation and temperature throughout the ice thickness. We propose to place instruments at the bedrock and in the ice on the center line of the ice stream. These data will allow us to constrain the relative importance of ice deformation vs. basal motion. Changing water pressure under the ice stream can alter the basal motion on very short timescales (hours to days). Higher water pressure in the subglacial drainage system can lead to higher ice stream velocities, and therefore greatly enhanced mass flux. Earlier attempts to drill through the ice stream center have not been successful, due to the great thickness (2500 m) and the cold temperature of the ice. We will improve on our hot water drilling system used earlier to drill through to bedrock at the ice stream margins. We intend to test our new drilling system at Swiss Camp on the ice sheet far from ice stream influence. We will deploy the same instruments as described above. These data will allow us to observe the influence of increasing melt water fluxes on the dynamics of the ice sheet close to the margins. The data will be interpreted with help of a finite element ice stream model that includes ice deformation (full equations), advection and diffusion of heat, phase transition, basal hydrology, and calving of the floating ice.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
The mass balance of the Greenland Ice Sheet is one of the major unknowns in predicting seal level change. Snow accumulation and melt seem to be balanced, as rising temperatures are partly compensated by higher precipitation in central parts of the ice sheet. The dynamics of the outlet ice streams is largely independent of mass balance, but it can significantly affect the overall mass balance of the ice sheet. More mass flux through faster ice streams directly affects the melt water flux into the North Atlantic, and therefore ocean circulation and sea level. How sensitive polythermal polar ice streams are to climate change (mainly melt water influx) is as yet unknown. Jakobshavn Isbrae produces a large fraction of the icebergs in the North Atlantic. Changes in this ice stream affect deep water production, iceberg frequency and size. This affects ocean traffic, fishing and subsistence hunting on the Greenland West Coast.

What international collaboration is involved in this project?
The main partners in this project are University of Alaska, Fairbanks (USA) and ETH Zurich (Switzerland). We invite collaborators with interest in hydrology, ocean currents and fisheries.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
West Greenland ice sheet (Ilulisat/Jakobshavn Area) Jakobshavn Isbrae 69.2N 49W Swiss Camp 69.6N 49.3W

Approximate timeframe(s) for proposed field activities:
Arctic: 05/2007-07/2007      05/2008-08/2008      
Antarctic: n/a

Significant facilities will be required for this project:
Transportation from Illulisat to the Greenland ice sheet. This can be accomplished with commercial carriers (e.g. Groenlandsfly). Other drilling and field equipment is available or will be purchased.

Will the project leave a legacy of infrastructure?
An improved hot water drilling system capable of drilling through cold ice streams. Finite Element ice stream code.

How is it envisaged that the required logistic support will be secured?
Own national polar operator
Commercial operator
Own support

In addition to commercial operators, we will seek support from the US NSF Arctic Logistics Program.

Has the project been "endorsed" at a national or international level?

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
New

This is a new project, although it builds on experience and infrastructure from earlier projects funded by US NSF, Swiss NSF, and NASA

How will the project be organised and managed?
[UAF: University of Alaska, Fairbanks, USA, ETHZ: Swiss Federal Institute of Technology, Zurich, Switzerland] Deep drilling system: development, test: UAF, ETHZ Data recording and transmission system: development, test: ETHZ Field work: UAF, ETHZ Data ev

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
Project with local school in Illulisat: facts, history of their local ice stream. Climate changes in their local environment (ice stream) and world wide. Involving teachers in the field work. Invite local school to operate measurements of fjord temperatures / icebergs / calving activity. Involvement of Journalists/TV in the field work.

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Data will be available at WDC (Glaciology) Boulder, and the websites of the institutes UAF/ETHZ. Data will be stored in ASCII (Borehole data, time series) and NetCDF files. The Finite Element code builds on open source libraries, and the ice stream model will be published under an open source license.

How is it proposed to fund the project?
Application for grants from NSF Office of Polar Programs, Swiss National Science Foundation, and ETH Zurich, Switzerland.

Is there additional information you wish to provide?
This proposal fulfills all the characteristics for an IPY proposal as outlined in "A Framework for the International Polar Year 2007/2008".

PROPOSER DETAILS

Pro Martin Truffer
Geophysical Institute
University of Alaska Fairbanks
Fairbanks, AK
99775
USA

Tel: 1-907-474-5359
Mobile: no
Fax: 1-907-474-7290
Email:

Other project members and their affiliation