[en] Neighboring tidewater glaciers often exhibit asynchronous dynamic behavior, despite relatively uniform regional atmospheric and oceanic forcings. This variability may be controlled by a combination of local factors, including glacier and fjord geometry, fjord heat content and circulation, and glacier surface melt. In order to characterize and understand contrasts in adjacent tidewater glacier and fjord dynamics, we made coincident ice-ocean-atmosphere observations at high temporal resolution (minutes to weeks) within a 10 000 km2 area near Uummannaq, Greenland. Water column velocity, temperature and salinity measurements reveal systematic differences in neighboring fjords that imply contrasting circulation patterns. The observed ocean velocity and hydrography, combined with numerical modeling, suggest that subglacial discharge plays a major role in setting fjord conditions. In addition, satellite remote sensing of seasonal ice flow speed and terminus position reveal both speedup and slow-down in response to melt, as well as differences in calving style among the neighboring glaciers. Glacier force budgets and modeling also point toward subglacial discharge as a key factor in glacier behavior. For the studied region, individual glacier and fjord geometry modulate subglacial discharge, which leads to contrasts in both fjord and glacier dynamics.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Bartholomaus, Timothy C.; University of Texas Institute for Geophysics, Austin, United States
Stearns, Leigh A.; University of Kansas, Lawrence, United States
Sutherland, David A.; University of Oregon, Eugene, United States
Shroyer, Emily L.; Oregon State University, Corvallis, United States
Nash, Jonathan D.; Oregon State University, Corvallis, United States
Walker, Ryan T.; University of Maryland, NASA Goddard Space Flight Center, Greenbelt, United States
Catania, Ginny; University of Texas Institute for Geophysics, Austin, United States
Felikson, Denis; University of Texas Institute for Geophysics, Austin, United States
Carroll, Dustin; University of Oregon, Eugene, United States
Fried, Mason J.; University of Texas Institute for Geophysics, Austin, United States
Noël, Brice ; Université de Liège - ULiège > Département de géographie > Climatologie et Topoclimatologie ; Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, Utrecht, Netherlands
Van Den Broeke, Michiel R.; Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, Utrecht, Netherlands
Language :
English
Title :
Contrasts in the response of adjacent fjords and glaciers to ice-sheet surface melt in West Greenland
Alley RB and 5 others (1998) How glaciers entrain and transport basal sediment: physical constraints. Quat. Sci. Rev., 16(9), 1017-1038
Amundson JM and 5 others (2008) Glacier, fjord, and seismic response to recent large calving events, Jakobshavn Isbræ, Greenland. Geophys. Res. Lett., 35(22), 1-5 (doi: 10.1029/ 2008GL035281)
Andrews LC and 7 others (2014) Direct observations of evolving subglacial drainage beneath the Greenland Ice Sheet. Nature, 514 (7520), 80-83 (doi: 10.1038/nature13796)
Aström JA and 10 others (2014) Termini of calving glaciers as selforganized critical systems. Nat. Geosci., 7(12), 874-878 (doi: 10.1038/NGEO2290)
Bartholomaus TC, Anderson RS and Anderson SP (2011) Growth and collapse of the distributed subglacial hydrologic system of Kennicott Glacier, Alaska, USA, and its effects on basal motion. J. Glaciol., 57(206), 985-1002
Bartholomaus TC, Larsen CF, O'Neel S and West ME (2012) Calving seismicity from iceberg-sea surface interactions. J. Geophys. Res., 117(F4), 1-16 (doi: 10.1029/2012JF002513)
Bartholomaus TC, Larsen CF and O'Neel S (2013) Does calving matter Evidence for significant submarine melt. Earth Planet. Sci. Lett., 380, 21-30
Bevan SL, Luckman AJ and Murray T (2012) Glacier dynamics over the last quarter of a century at Helheim, Kangerdlugssuaq and 14 other major Greenland outlet glaciers. Cryosphere, 6(5), 923-937 (doi: 10.5194/tc-6-923-2012)
Bindschadler RA (1983) The importance of pressurized subglacial water in separation and sliding at the glacier bed. J. Glaciol., 29(101), 3-19
Bjørk AA and 8 others (2012) An aerial view of 80 years of climaterelated glacier fluctuations in southeast Greenland. Nat. Geosci., 5, 427-432 (doi: 10.1038/NGEO1481)
Bjørk AA, Kruse LM and Michaelsen PB (2015) Getting Greenland's glaciers right-a new dataset of all official Greenlandic glacier names. Cryopshere, 9, 2215-2218
Blatter H (1995) Velocity and stress fiels in grounded glaciers: a simple algorithm for including deviatoric stress gradients. J. Glaciol., 41(138), 333-344
Carr JR and 9 others (2015) Basal topographic controls on rapid retreat of Humboldt Glacier, northern Greenland. J. Glaciol., 61(225), 137-150 (doi: 10.3189/2015JoG14J128)
Carroll D and 5 others (2015) Modeling turbulent subglacial meltwater plumes: implications for fjord-scale buoyancy-driven circulation. J. Phys. Ocean., 45(8), 2169-2185 (doi: 10.1175/ JPO-D-15-0033.1)
Cassotto R, Fahnestock M, Amundson JM, Truffer M and Joughin I (2015) Seasonal and interannual variations in ice melange and its impact on terminus stability, Jakobshavn Isbrae, Greenland. J. Glaciol., 61(225), 76-88 (doi: 10.3189/2015JoG13J235)
Chauché N and 8 others (2014) Ice-ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers. Cryosphere, 8(4), 1457-1468 (doi: 10.5194/tc-8-1457-2014)
Chu VW, Smith LC, Rennermalm AK, Forster RR and Box JE (2012) Hydrologic controls on coastal suspended sediment plumes around the Greenland Ice Sheet. Cryosphere, 6, 1-19 (doi: 10.5194/tc-6-1-2012)
Csatho BM and 9 others (2014) Laser altimetry reveals complex pattern of Greenland ice sheet dynamics. Proc. Natl. Acad. Sci. U.S.A., 111(52), 18478-18483 (doi: 10.1073/pnas.1411680112)
Dowdeswell JA and 5 others (2014) Late quaternary ice flow in a West Greenland fjord and cross-shelf trough system: submarine landforms from Rink Isbrae to Uummannaq shelf and slope. Quat. Sci. Rev., 92, 292-309 (doi: 10.1016/j.quascirev.2013.09.007)
Enderlin EM and 5 others (2014) An improved mass budget for the Greenland ice sheet. Geophys. Res. Lett., 41, 1-7 (doi: 10.1002/2013GL059010)
Fried MJ and 8 others (2015) Distributed subglacial discharge drives significant submarine melt at a Greenland tidewater glacier. Geophys. Res. Lett., 42(21), 9328-9336 (doi: 10.1002/ 2015GL065806)
Gade HG (1979) Melting of ice in sea water: a primitive model with application to the Antarctic ice shelf and icebergs. J. Phys. Ocean., 9(1), 189-198
Gladish CV, Holland DM, Rosing-Asvid A, Behrens JW and Boje J (2015) Oceanic boundary conditions for Jakobshavn glacier: part I. Variability and renewal of Ilulissat Icefjord waters, 2001-2014. J. Phys. Ocean., 45(1), 3-32 (doi: 10.1175/JPO-D-14-0044.1)
Harig C and Simons FJ (2012) Mapping Greenland's mass loss in space and time. Proc. Natl. Acad. Sci. U.S.A., 109(49), 19934-19937 (doi: 10.1073/pnas.1206785109)
Hewitt IJ (2013) Seasonal changes in ice sheet motion due to melt water lubrication. Earth Planet. Sci. Lett., 371-372, 16-25 (doi: 10.1016/j.epsl.2013.04.022)
Holland DM, Thomas RH, de Young B, Ribergaard MH and Lyberth B (2008) Acceleration of Jakobshavn Isbræ triggered by warm subsurface ocean waters. Nat. Geosci., 1(10), 659-664 (doi: 10.1038/ngeo316)
Howat IM, Joughin I, Tulaczyk S and Gogineni S (2005) Rapid retreat and acceleration of Helheim Glacier, east Greenland. Geophys. Res. Lett., 32(22), L22502 (doi: 10.1029/2005GL024737)
Howat IM, Box JE, Ahn Y, Herrington A and McFadden EM (2010) Seasonal variability in the dynamics of marine-terminating outlet glaciers in Greenland. J. Glaciol., 56(198), 601-613 (doi: 10.3189/002214310793146232)
Howat IM, Negrete A and Smith BE (2014) The Greenland Ice Mapping Project (GIMP) land classification and surface elevation data sets. Cryosphere, 8(4), 1509-1518 (doi: 10.5194/tc-8-1509-2014)
James TD, Murray T, Selmes N, Scharrer K and Leary MO (2014) Buoyant flexure and basal crevassing in dynamic mass loss at Helheim Glacier. Nat. Geosci., 7, 593-596 (doi: 10.1038/ NGEO2204)
Jenkins A (2011) Convection-driven melting near the grounding lines of ice shelves and tidewater glaciers. J. Phys. Ocean., 41 (12), 2279-2294
Joughin I, Smith BE, Howat IM, Scambos T and Moon T (2010) Greenland flow variability from ice-sheet-wide velocity mapping. J. Glaciol., 56(197), 415-430 (doi: 10.3189/ 002214310792447734)
Joughin I and 6 others (2012) Seasonal to decadal scale variations in the surface velocity of Jakobshavn Isbrae, Greenland: observation and model-based analysis. J. Geophys. Res., 117, 1-20 (doi: 10.1029/2011JF002110)
Kienholz C, Hock R and Arendt AA (2013) A new semi-automatic approach for dividing glacier complexes into individual glaciers. J. Glaciol., 59(217), 925-937 (doi: 10.3189/2013JoG12J138)
Kjaer KH and 13 others (2012) Aerial photographs reveal late-20thcentury dynamic ice loss in Northwestern Greenland. Science (80-.), 337, 569-573
Larour E, Seroussi H, Morlighem M and Rignot E (2012) Continental scale, high order, high spatial resolution, ice sheet modeling using the Ice Sheet System Model (ISSM). J. Geophys. Res., 117 (F01022), 1-20
Lea JM and 8 others (2014) Terminus-driven retreat of a major southwest Greenland tidewater glacier during the early 19th century: insights from glacier reconstructions and numerical modelling. J. Glaciol., 60(220), 333-344 (doi: 10.3189/2014JoG13J163)
Luthi M, Funk M, Iken A, Gogineni S and Truffer M (2002) Mechanisms of fast flow in Jakobshavn Isbrae, West Greenland: part III. Measurements of ice deformation, temperature and crossborehole conductivity in boreholes to the bedrock. J. Glaciol., 48 (162), 369-385 (doi: 10.3189/172756502781831322)
MacAyeal DR (1993) A tutorial on the use of control methods in icesheet modeling. J. Glaciol., 39(131), 91-98
MacGregor JA, Catania GA, Markowski MS and Andrews AG (2012) Widespread rifting and retreat of ice-shelf margins in the eastern Amundsen Sea Embayment between 1972 and 2011. J. Glaciol., 58(209), 458-466 (doi: 10.3189/2012JoG11J262)
McFadden EM, Howat IM, Joughin I, Smith BE and Ahn Y (2011) Changes in the dynamics of marine terminating outlet glaciers in west Greenland (2000-2009). J. Geophys. Res., 116 (F02022), 1-16 (doi: 10.1029/2010JF001757)
McNabb RW and Hock R (2014) Alaska tidewater glacier terminus positions, 1948-2012. J. Geophys. Res. Earth Surf., 119, 1-15 (doi: 10.1002/2013JF002915)
Moon T and Joughin I (2008) Changes in ice front position on Greenland's outlet glaciers from 1992 to 2007. J. Geophys. Res., 113(F2), 1-10 (doi: 10.1029/2007JF000927)
Moon T, Joughin I, Smith B and Howat I (2012) 21st-Century evolution of Greenland outlet glacier velocities. Science (80), 336, 576-578
Moon T and 6 others (2014) Distinct patterns of seasonal Greenland glacier velocity. Geophys. Res. Lett., 41, 7209-7216 (doi: 10.1002/2014GL061836)
Moon T, Joughin I and Smith B (2015) Seasonal to multiyear variability of glacier surface velocity, terminus position, and sea ice/ice mélange in northwest Greenland. J. Geophys. Res. Earth Surf., 120, 818-833 (doi: 10.1002/2015JF003494)
Morlighem M, Rignot E, Mouginot J, Seroussi H and Larour E (2014) Deeply incised submarine glacial valleys beneath the Greenland ice sheet. Nat. Geosci., 7, 418-422 (doi: 10.1038/NGEO2167)
Motyka RJ, Truffer M, Kuriger EM and Bucki AK (2006) Rapid erosion of soft sediments by tidewater glacier advance: Taku Glacier, Alaska, USA. Geophys. Res. Lett., 33(24), L24504 (doi: 10.1029/2006GL028467)
Motyka RJ, Dryer WP, Amundson J, Truffer M and Fahnestock M (2013) Rapid submarine melting driven by subglacial discharge, LeConte Glacier, Alaska. Geophys. Res. Lett., 40, 1-6 (doi: 10.1002/grl.51011)
Murray T and 10 others (2010) Ocean regulation hypothesis for glacier dynamics in southeast Greenland and implications for ice sheet mass changes. J. Geophys. Res., 115(F3), 1-15 (doi: 10.1029/2009JF001522)
Murray T and 9 others (2015) Dynamics of glacier calving at the ungrounded margin of Helheim Glacier, southeast Greenland. J. Geophys. Res. Earth Surf., 120(6), 964-982 (doi: 10.1002/ 2015JF003531)
Nick FM, Vieli A, Howat IM and Joughin I (2009) Large-scale changes in Greenland outlet glacier dynamics triggered at the terminus. Nat. Geosci., 2(2), 110-114 (doi: 10.1038/NGEO394)
Noël B and 5 others (2015) Evaluation of the updated regional climate model RACMO2.3: summer snowfall impact on the Greenland ice sheet. Cryosphere, 9(5), 1831-1844 (doi: 10.5194/tc-9-1831-2015)
O'Neel S, Pfeffer WT, Krimmel R and Meier M (2005) Evolving force balance at Columbia Glacier, Alaska, during its rapid retreat. J. Geophys. Res., 110(F3), 1-18 (doi: 10.1029/2005JF000292)
Pattyn F (2003) A new three-dimensional higher-order thermomechanical ice sheet model: basic sensitivity, ice stream development, and ice flow across subglacial lakes. J. Geophys. Res., 108(B8), 1-15 (doi: 10.1029/2002JB002329)
Rignot E and Mouginot J (2012) Ice flow in Greenland for the International Polar Year 2008-2009. Geophys. Res. Lett., 39 (11) (doi: 10.1029/2012GL051634)
Rignot E, Fenty I, Menemenlis D and Xu Y (2012) Spreading of warm ocean waters around Greenland as a possible cause for glacier acceleration. Ann. Glaciol., 53(60), 257-266 (doi: 10.3189/ 2012AoG60A136)
Sciascia R, Straneo F, Cenedese C and Heimbach P (2013) Seasonal variability of submarine melt rate and circulation in an East Greenland fjord. J. Geophys. Res., 118, 1-15 (doi: 10.1002/ jgrc.20142)
Shepherd A and 45 others (2012) A reconciled estimate of ice-sheet mass balance. Science (80-.), 338, 1183-1189 (doi: 10.1126/ science.1228102)
Shreve RL (1972) Movement of water in glaciers. J. Glaciol., 11(62), 205-214
Slater DA, Nienow PW, Cowton TR, Goldberg DN and Sole AJ (2015) Effect of near-terminus subglacial hydrology on tidewater glacier submarine melt rates. Geophys. Res. Lett., 42, 1-8 (doi: 10.1002/2014GL062494)
Stearns LA and 6 others (2015) Glaciological and marine geological controls on terminus dynamics of Hubbard Glacier, southeast Alaska. J. Geophys. Res. Earth Surf., 120, 1065-1081 (doi: 10.1002/2014JF003341)
Straneo F and 6 others (2011) Impact of fjord dynamics and glacial runoff on the circulation near Helheim Glacier. Nat. Geosci., 4 (5), 322-327 (doi: 10.1038/ngeo1109)
Straneo F and 8 others (2012) Characteristics of ocean waters reaching Greenland's glaciers. Ann. Glaciol., 53(60), 202-210 (doi: 10.3189/2012AoG60A059)
Straneo F and 15 others (2013) Challenges to understanding the dynamic response of Greenland's marine terminating glaciers to oceanic and atmospheric forcing. Bull. Amer. Meteor. Soc., 94(8), 1131-1144 (doi: 10.1175/BAMS-D-12-00100.1)
Sutherland DA, Straneo F and Pickart RS (2014) Characteristics and dynamics of two major Greenland glacial fjords. J. Geophys. Res. Ocean., 119, 3767-3791 (doi: 10.1002/2013JC009786)
Tedstone AJ, Nienow PW, Gourmelen N and Sole AJ (2014) Greenland ice sheet annual motion insensitive to spatial variations in subglacial hydraulic structure. Geophys. Res. Lett., 41, 8910-8917 (doi: 10.1002/2014GL062386)
Thomas RH (2004) Force-perturbation analysis of recent thinning and acceleration of Jakobshavn Isbrae, Greenland. J. Glaciol., 50(168), 57-66 (doi: 10.3189/172756504781830321)
van der Veen CJ and Whillans IM (1989) Force budget: I. Theory and numerical methods. J. Glaciol., 35(119), 53-60
van der Veen CJ, Plummer JC and Stearns LA (2011) Controls on the recent speed-up of Jakobshavn Isbræ, West Greenland. J. Glaciol., 57(204), 770-782
van der Veen CJ, Stearns LA, Johnson J and Csatho B (2014) Flow dynamics of Byrd Glacier, East Antarctica. J. Glaciol., 60(224), 1053-1064 (doi: 10.3189/2014JoG14J052)
Veitch SA and Nettles M (2012) Spatial and temporal variations in Greenland glacial-earthquake activity, 1993-2010. J. Geophys. Res., 117, 1-20 (doi: 10.1029/2012JF002412)
Vernon CL and 6 others (2013) Surface mass balance model intercomparison for the Greenland ice sheet. Cryosphere, 7, 599-614 (doi: 10.5194/tcd-6-3999-2012)
