200 likes | 302 Views
Sarah Boon(1); Dave Burgess(2); Luke Copland(3); Gwenn Flowers(4); Jeff Kavanaugh(2); Shawn Marshall(5); Martin Sharp(2); Lev Tarasov(6) (1)U of N.B.C, (2)U. of Alberta, (3)U. of Ottawa, (4)Simon Fraser, (5)U. of Calgary, (6)M.U.N.
E N D
Sarah Boon(1); Dave Burgess(2); Luke Copland(3); Gwenn Flowers(4); Jeff Kavanaugh(2); Shawn Marshall(5); Martin Sharp(2); Lev Tarasov(6) (1)U of N.B.C, (2)U. of Alberta, (3)U. of Ottawa, (4)Simon Fraser, (5)U. of Calgary, (6)M.U.N. Global warming and polar tidewater glacier response: A Canadian IPY project on Belcher Glacier, Nunavut B.Beauchamp
THE CLIMATE SYSTEM IS MORE SENSITIVE THAN WE THOUGHT Mauna Loa CO2 record Global Mean Annual Air Temperature c.f. IPCC Scenarios Global Mean Sea Level c.f. IPCC Scenarios Rahmstorf et al, Science Express, Feb 2007
WHAT’S DRIVING THE SEA LEVEL RISE ?? Luthcke et al, Science, 2006 Alley et al., Annals of Glaciology, in press ENHANCED MASS LOSS FROM GREENLAND
WHY THE ENHANCED LOSS? Outlet Glacier velocities m/yr Glacier Earthquakes Rignot & Kanagaratnam, Science, 2006 Ekstrom et al, Science, 2006 ACCELERATED OUTLET GLACIER FLOW
OUTLET GLACIER RETREAT, THINNING AND ICEBERG CALVING Helheim Glacier 2000 2004 Thickness Change Frontal Retreat Velocity I. Howat et al., GRL, 2005
WHAT’S DRIVING THESE CHANGES? • Two main hypotheses: • From the top – increased or more widespread penetration of surface meltwater to the glacier bed enhances sliding • From the bottom – terminus destabilisation by flotation (due to rising sea level or thinning caused by increased surface or marine melt) reduces flow resistance • But which is it ? Hard to measure in Greenland A. Gardner
IPY GLACIODYN: International • Researchers from 17 countries • Tidewater Arctic glaciers – role of dynamics in response to climate warming • Canada, Alaska, Greenland, Iceland, Svalbard, Russia B.Danielson
IPY GLACIODYN Canada Canadian Participants Martin Sharp, Jeff Kavanaugh, (U. Alberta) Shawn Marshall (U. Calgary), Gwenn Flowers (SFU) Sarah Boon (UNBC), Luke Copland (U. Ottawa) Trevor Bell, Lev Tarasov (Memorial) Dave Burgess,Laurence Gray (CCRS) International Collaborators Tony Payne, Jemma Wadham (Bristol University, UK) Bernd Kulessa (University of Wales, Swansea) Andy Smith (British Antarctic Survey)
Canadian site: Devon Island Ice Cap Queen Elizabeth Islands Devon
Goals • Develop high order coupled model of outlet glacier dynamics • incorporate surface mass balance, glacier hydrology, ice flow and iceberg calving • Collect detailed field and remotely sensed data • Design, initialize, drive, and validate model • Run model • Explore Belcher Glacier response to climate change • atmospheric and oceanic climate • amount and distribution of surface water inputs to glacier bed • Ice dynamics, terminus stability and iceberg calving • What are the important processes?
Methods: Modelling snow • Surface mass balance model • Whole ice cap flow model • Coupled hydrology/ thermomechanical outlet glacier flow model • Iceberg calving mechanics Lev Tarasov G. Flowers
Methods: Surface Processes & Properties • Mass balance • radar, ice cores, AWS, stakes, remote sensing of summer melt • Hydrology & Drainage • remote sensing, time lapse photography, hydrometric measurements, • Topography • Kinematic GPS, Airborne laser altimetry, Photogrammetry B.Danielson Surface elevation change (m/yr) Distance from Glacier Head (km) S. Boon Thickness Changes 1960-2005
Methods: Sub-surface characteristics M. Davis • Subglacial topography • RES, GPR • Bed properties and their temporal variability • seismic reflection and monitoring NOAA W.Krabill
Methods: Offshore bathymetry and water column properties • RCGS Amundsen
Methods: Ice velocities • Remote sensing • InSAR • Field measurements • wireless GPS D. Burgess D. Burgess et al., J.Glaciology, 2005
Key questions (1) • On what timescale does Belcher Glacier respond to climate warming? • How is glacier response regulated by changes in the rate and mechanism of ice flow? If so, what causes these changes? • How do these changes amplify those caused by surface mass balance alone? F. Cawkwell
Key questions (2) • Are changes in flow dynamics and iceberg calving related, and how? • What controls the calving rate and its variation over time – is ocean climate important? Vexcel A.Gardner
Challenges • NSERC IPY/PCSP Logistics mis-communication: dollar stretching • Polar Bears
Funding • NSERC • IPY SRO • RTI • Discovery Grant • Northern Research Supplement • CFI • ASRIP, OIT • ArcticNet • PCSP F. Cawkwell