Jenna Hill NASA 2002 Map Formation history and the LGM Larsen B Ice Shelf Tributaries Fracture propagation Lateral rifting Surface meltwater Ice shelf geometry Uniaxial stress Pinning points ID: 459116
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Slide1
Dynamic Changes of the Antarctic Peninsula in the Past 50 Years
Jenna Hill
(NASA, 2002)Slide2
MapFormation history and the LGMLarsen B Ice Shelf
TributariesFracture propagationLateral riftingSurface meltwaterIce shelf geometry
Uniaxial stressPinning pointsShear zonesOverview
OutlineSlide3Slide4
Early Oligocene
Opening of Drake PassageAntarctic circumpolar current
Mountain glaciationLGM
FormationSlide5
10ka ice sheet, 6 week collapse
3200km^2Flow response by adjacent glaciers
Welch Mountain RangeTributary glaciers tidewater glaciers
Larsen B Ice Shelf
(NASA, 2002)Slide6
Larsen B Ice Shelf Tributaries
(
Wuite
et al., 2015)
33 tributary glaciers
Combined mass loss of 8.4Gt/a between 2001-2006.
Other studies indicate flow velocity has remained fairly constant since.Slide7
Fracture Densities
(Albrecht and
Levermann, 2012)
Initiated by principal stresses
Weakening mechanisms
Ice shelf stability and softening
Fracture propagation
Larsen
A
Larsen
BSlide8
Rapid thinning and extensional stress parallel to flow
Downward propagation of
meltwater through crevasses
Acceleration of fragmentation
Internal Plumbing
Moulin
Recent large-scale rift systems
Rifting and Surface
Meltwater
(Baker, 2011)
(Gould, 2013)Slide9
Jones Ice Shelf
Significant depletion after areal advancementTwo ice frontsThe role of geometry and lateral forces
(Cook and Vaughan, 2010)
(Cook and Vaughan, 2010)Slide10
EmbaymentPinning pointsUniaxial compression
Jones Ice ShelfConvergent vs. Divergent mouthLateral stresses
Ice Shelf Geometry and Stress
(
Doake
, 2001)Slide11
Ice rises
Major factor in retreat of Wordie Ice Shelf
Periods of stasis and rapid retreatPinning pointsNonuniform pressure
overall tension broken
Wedges, splitting, fracture propagation
Ice Rise PinningSlide12
Differences in flow unit velocityWeakening of sutures
Structural irregularities and uneven stressLinear fracturesShear margins
Sutures and shearing
(
Hambrey
, 2012)Slide13
Tributary
flow
Lateral riftingFracture propagationSurface
meltwater
and internal plumbing
Ice shelf geometry and lateral compression
Pinning points
Weakening of shear zones
Factors in recession
(
Colla
, 2011)Slide14
Böning, C., A.
Dispert, M. Visbeck, S. Rintoul, and F. Schwarzkopf, 2008: The response of Antarctic Circumpolar Current to recent climate change,
Nature Geoscience, v. 1, p. 864-869.Cook, A. J. and Vaughan, D. G, 2010: Overview of areal changes of the ice shelves on
the Antarctic Peninsula over the past 50 years,
The
Cryosphere
, v. 4, p. 77–98.
Cook, A. J., D. G. Vaughan, A. J.
Luckman
, and T. Murray, 2014: A new Antarctic Peninsula
glacier basin inventory and observed area changes since the 1940s,
Antarctic Science,
v. 6, p. 614-624.
Cook, A. J., A. J. Fox, D. G. Vaughan, and J.G.
Ferrigno
, 2005: Retreating Glacier
Fronts on the Antarctic Peninsula over the Past Half-Century.
Science 22,
v. 309, p. 541-544.
Davies, B.J., J.L.
Carrivick
, N.F.
Glasser
, M.J.
Hambrey
, and J. L.
Smelle
, 2012:
Antarctic Peninsula Ice Sheet evolution during the Cenozoic Era,
Quaternary Science Reviews
, v. 6, p. 30-66.
Denton, G. H., and T. J. Hughes, 2002: Reconstructing the Antarctic Ice shelf at the Last Glacial
Maximum.
Quaternary Science Reviews
, v. 21, p. 193-202.
Fox, A. J. and Vaughan, D. G., 2005: The retreat of Jones Ice Shelf, Antarctic Peninsula.
Journal
of Glaciology
, v. 51, p. 555–560.
Glasser
, N. F. and T. A.
Scambos
: 2008: A structural glaciological analysis of the 2002
Larsen B ice-shelf collapse.
Journal of Glaciology
. v. 54, p. 3–16.
Huss, M. and D.
Farinotti
, 2014: A high-resolution bedrock map for the Antarctic Peninsula, v. 8, p. 1261-1273.Kushner, P., I. Held, and T. Delworth, 2001: Southern Hemisphere Atmospheric Circulation Response to Global Warming, Journal of Climate, v. 14, p. 2238-2249.Marshall, G., Orr, A., Lipsig, N., King, J., 2006: The Impact of a Changing Southern Hemisphere Annular Mode on Antarctic Peninsula Summer Temperatures. Journal of Climate, v. 150, p. 5388-5404 Matsuoka, K., R. Hindmarch, G. Moholdt, M. Bentley, H. Pritchard, J. Brown, h. Conway, R. Drews, G. Durand, D. Goldberg, T. Hattermann, J. Kingslake, J. Lenaerts, C. Martín, R. Mulvaney, K. Nicholls, F. Pattyn, N. Ross, T. Scambos, and P. Whitehouse, 2015: Antarctic rises and rumples: Their properties and significance for ice-sheet dynamics and evolution. Earth-Science Reviews, v. 150, p. 724-745.Naish, T., R. Powell, R. Levy, G. Wilson, R. Scherer, F. Talarico, L. Krissek, F. Niessen, M. Pompilio, T. Wilson, L. Carter, R. DeCnto, P. Huybers, R. McKay, D. Pollard, J. Rocc, D. Winter, P. Barrett, G. Browne, R. Cody, E. Cowan, J. Crampton, G. Dunbar, N. Dunbar, F. Florindo, C. Gebhardt, I. Graham, M. Hannah, D. Hansaraj, D. Harwood, D. Helling, S. Henrys, L. Hinnov, G. Kuhn, P. Kyle, A. Läufer, P. Maffioli,, D. Magens, K. Mandernack, W. McIntosh, C. Millan, R. Morin, C. Ohneiser, T. Paulsen, D. Persico, I. Raine, J. Reed, C. Riesselman, L. Sagnotti, D. Schmitt, C. Sjunneskog, P. Strong, M. Taviani, S. Vogel, T. Wilch, and T. Williams, 2009: Obliquity-paced Pliocene West Antarctic Ice Sheet Oscillations. Nature, v. 458, p. 322-328.Pritchard, S., S. Ligtenberg, H. Fricker, D. Vaughan, M. Broeke, and L. Padman, 2012: Antarctic ice-sheet loss driven by basal melting of ice shelves. Nature, v. 484, p. 502-505.Scambos, T.A., J. A. Bohlander, C. A. Shuman, and P. Skvarca, 2004: Glacier acceleration and thinning after ice shelf collapse in the Larsen B embayment, Antarctica. Geophysical Research Letters, v. 31, p. 402-406.Scambos, T. A., H. A. Fricker, C. Liu, J. Bohlander, J. Fastook, A. Sargent, R. Massom, and A. Wu, 2009: Ice shelf disintegration by plate bending and hydro-fracture: Satellite observations and model results of the 2008 Wilkins ice shelf break-ups. Earth and Planetary Science Letters, v. 280, p. 51-60.SCAR, 2006: A Brief Account of the Evolution of SCAR (The Scientific Committee on Antarctic Research). At http://www.scar.org/scar_media/documents/aboutscar/Evolution_of_SCAR_1958-2006.pdf (accessed 20 November, 2014)Shepherd, A., Wingham, D., Payne, T., and P. Skvarca, 2003: Larsen ice shelf has progressively thinned. Science, v. 302, p. 856–859.Siegert, M.J., Florindo, F., 2009. Antarctic climate evolution. Philadelphia, PA: Elsevier; 11 Pp.Stewart, J. (2011) Antarctic Encyclopedia McFarland & Company Inc, New York. 1776 pp.Vieli, A., Payne, A. J., Shepherd, A., and Z. Du, 2007: Causes of precollapse changes of the Larsen B ice shelf: Numerical modelling and assimilation of satellite observations. Earth Planet. v. 259, p. 297–306.
Sources