World Library  

Add to Book Shelf
Flag as Inappropriate
Email this Book

Present Dynamics and Future Prognosis of a Slowly Surging Glacier : Volume 4, Issue 4 (01/10/2010)

By Flowers, G. E.

Click here to view

Book Id: WPLBN0003990153
Format Type: PDF Article :
File Size: Pages 38
Reproduction Date: 2015

Title: Present Dynamics and Future Prognosis of a Slowly Surging Glacier : Volume 4, Issue 4 (01/10/2010)  
Author: Flowers, G. E.
Volume: Vol. 4, Issue 4
Language: English
Subject: Science, Cryosphere, Discussions
Collections: Periodicals: Journal and Magazine Collection (Contemporary), Copernicus GmbH
Publication Date:
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications


APA MLA Chicago

Pimentel, S., Roux, N., & Flowers, G. E. (2010). Present Dynamics and Future Prognosis of a Slowly Surging Glacier : Volume 4, Issue 4 (01/10/2010). Retrieved from

Description: Department of Earth Sciences, Simon Fraser University, Burnaby, BC, Canada. Glacier surges are a well-known example of an internal dynamic oscillation whose occurrence is not a direct response to the external climate forcing, but whose character (e.g. period, mechanism) may depend on the glacier's environmental or climate setting. We examine the dynamics of a small (~5 km2) valley glacier in the Yukon Territory of Canada, where two previous surges have been photographically documented and an unusually slow surge is currently underway. To characterize the dynamics of the present surge, and to speculate on the future of this glacier, we employ a higher-order flowband model of ice dynamics with a Coulomb-friction sliding law in both diagnostic and prognostic simulations. Diagnostic (force balance) calculations capture the measured ice-surface velocity profile only when high basal water pressures (55–90% of flotation) are prescribed over the central region of the glacier, consistent with where evidence of the surge has been identified. This leads to sliding accounting for 50–100% of the total surface motion. Prognostic simulations, where the glacier geometry evolves in response to a prescribed surface mass balance, reveal a significant role played by a large bedrock bump beneath the current equilibrium line of the glacier. This bump provides resistance to ice flow sufficient to cause the formation of a bulge in the ice-surface profile. We suggest that the bedrock bump contributes to the propensity for surges in this glacier, such that conditions suppressing ice-bulge formation over the bump may also inhibit surges. In our calculations such a situation arises for sufficiently negative values of mass balance. Collectively, these results corroborate our interpretation of the current glacier flow regime as indicative of a slow surge, and confirm a relationship between surge incidence or character and the net mass balance. Our results also highlight the importance of glacier bed topography in controlling ice dynamics, as observed in many other glacier systems.

Present dynamics and future prognosis of a slowly surging glacier

Aðalgeirsdóttir, G., Björnsson, H., Pálsson, F., and Magnússon, E.: Analyses of a surging outlet glacier of Vatnajökull ice cap, Iceland, Ann. Glaciol., 42, 23–28, 2005.; Anonymous: Mass-balance terms, J. Glaciol., 8, 3–7, 1969.; Arendt, A. A., Echelmeyer, K. A., Harrison, W. D., Lingle, C. S., and Valentine, V. B.: Rapid wastage of Alaskan glaciers and their contribution to rising sea level, Science, 297, 382–386, 2002.; Arendt, A. A., Luthcke, S. B., Larsen, C. F., Abdalati, W., Krabill, W. B., and Beedle, M. J.: Validation of high-resolution grace mascon estimates of glacier mass changes in the St. Elias Mountains, Alaska, USA, using aircraft laser altimetry, J. Glaciol., 54, 778–787, 2008.; Barrand, N. E. and Sharp, M. J.: Sustained rapid shrinkage of Yukon glaciers since the 1957–1958 International Geophysical Year, Geophys. Res. Lett., 37, L07501, doi:10.1029/2009GL042030, 2010.; Belliveau, P.: Dynamics and hydrology of a small mountain glacier, B.Sc. thesis, Simon Fraser University, 2009.; Björnsson, H.: Hydrological characteristics of the drainage system beneath a surging glacier, Nature, 395, 771–774, 1998.; Berthier, E., Schiefer, E., Clarke, G. K. C., Menounos, B., and Rémy, F.: Contribution of Alaskan glaciers to sea-level rise derived from satellite imagery, Nat. Geosci., 3, 92–95, 2010.; Blatter, H.: Velocity and stress fields in grounded glaciers: a simple algorithm for including deviatoric stress gradients, J. Glaciol., 41, 333–344, 1995.; Budd, W. F.: A first simple model for periodically self-surging glaciers, J. Glaciol., 14, 3–21, 1975.; Clarke, G., Schmok, J., Ommanney, C., and Collins, S.: Characteristics of surge-type glaciers, J. Geophys. Res., 91, 7165–7180, 1986.; Glen, J. W.: The creep of polycrystalline ice, Proc. R. Soc. Lon. Ser.-A, 228, 519–538, 1955.; Clarke, G. K. C. and Blake, E. W.: Geometric and thermal evolution of a surge-type glacier in its quiescent state – Trapridge Glacier, Yukon Territory, Canada, 1969–89, J. Glaciol., 37, 158–169, 1991.; Clarke, G. K. C., Collins, S. G., and Thompson, D. E.: Flow, thermal structure, and subglacial conditions of a surge-type glacier, Can. J. Earth Sci., 21, 232–240, 1984.; Colinge, J. and Rappaz, J.: A strongly nonlinear problem arising in glaciology, Math. Model. Numer. Anal., 33, 395–406, 1999.; De Paoli, L.: Dynamics of a small surge-type glacier, St. Elias Mountains, Yukon Territory, Canada: characterization of basal motion using 1-D geophysical inversion, M.Sc. thesis, Simon Fraser University, 2009.; De Paoli, L. and Flowers, G. E.: Dynamics of a small surge-type glacier investigated using 1-D geophysical inversion, J. Glaciol., 55, 1101–1112, 2009.; Dowdeswell, J. A., Hamilton, G. S., and Hagen, J. O.: The duration of the active phase on surge-type glaciers – contrasts between Svalbard and other regions, J. Glaciol., 37, 388–400, 1991.; Dowdeswell, J. A., Hodgkins, R., Nuttall, A. M., Hagen, J. O., and Hamiltonf, G. S.: Mass-balance change as a control on the frequency and occurrence of glacier surges in Svalbard, Norwegian high arctic, Geophys. Res. Lett., 22, 2909–2912, 1995.; Eisen, O., Harrison, W. D., and Raymond, C. F.: The surges of Variegated Glacier, Alaska, USA, and their connection to climate and mass balance, J. Glaciol., 47, 351–358, 2001.; Eisen, O., Harrison, W. D., Raymond, C. F., and Echelmeyer, K. A.: Variegated Glacier, Alaska, USA: a century of surges, J. Glaciol., 51, 399–406, 2005.; Fowler, A.: A Theory of glacier surges, J. Geophys. Res., 92, 9111–9120, 1987.; Frappé, T.-P. and Clarke, G. K. C.: Slow surge of Trapridge Glacier, Yukon Territory, Canada, J. Geophys. Res.


Click To View

Additional Books

  • Mass Balance, Runoff and Surges of the B... (by )
  • Large Sensitivity of a Greenland Ice She... (by )
  • Ice Sheet Mass Loss Caused by Dust and B... (by )
  • Transition of Flow Regime Along a Marine... (by )
  • Snowdrift Modelling for Vestfonna Ice Ca... (by )
  • Glaciochemical Investigations on the Sub... (by )
  • Impact of Varying Debris Cover Thickness... (by )
  • Union Glacier: a New Exploration Gateway... (by )
  • Polynyas in a Dynamic-thermodynamic Sea-... (by )
  • Thresholds in the Sliding Resistance of ... (by )
  • Do Crustal Deformations Observed by Gps ... (by )
  • Evolution of Ice-shelf Channels in Antar... (by )
Scroll Left
Scroll Right


Copyright © World Library Foundation. All rights reserved. eBooks from Nook eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.