Now showing items 1-11 of 11

  • Airborne-radar and ice-core observations of annual snow accumulation over Thwaites Glacier, West Antarctica confirm the spatiotemporal variability of global and regional atmospheric models 

    Medley, Brooke; Joughin, Ian; Das, Sarah B.; Steig, Eric J.; Conway, Howard; Gogineni, S.; Criscitiello, Alison S.; McConnell, Joseph R.; Smith, B. E.; van den Broeke, Michiel R.; Lenaerts, Jan T. M.; Bromwich, D. H.; Nicolas, J. P. (John Wiley & Sons, 2013-07-26)
    We use an airborne-radar method, verified with ice-core accumulation records, to determine the spatiotemporal variations of snow accumulation over Thwaites Glacier, West Antarctica between 1980 and 2009. We also present a ...
  • Challenges to understanding the dynamic response of Greenland's marine terminating glaciers to oceanic and atmospheric forcing 

    Straneo, Fiamma; Heimbach, Patrick; Sergienko, Olga; Hamilton, Gordon S.; Catania, Ginny; Griffies, Stephen; Hallberg, Robert; Jenkins, Adrian; Joughin, Ian; Motyka, Roman; Pfeffer, W. Tad; Price, Stephen F.; Rignot, Eric; Scambos, Ted; Truffer, Martin; Vieli, Andreas (American Meteorological Society, 2013-08)
    The recent retreat and speedup of outlet glaciers, as well as enhanced surface melting around the ice sheet margin, have increased Greenland's contribution to sea level rise to 0.6 ± 0.1 mm yr−1 and its discharge of ...
  • Constraining the recent mass balance of Pine Island and Thwaites glaciers, West Antarctica, with airborne observations of snow accumulation 

    Medley, Brooke; Joughin, Ian; Smith, B. E.; Das, Sarah B.; Steig, Eric J.; Conway, Howard; Gogineni, S.; Lewis, Cameron; Criscitiello, Alison S.; McConnell, Joseph R.; van den Broeke, Michiel R.; Lenaerts, Jan T. M.; Bromwich, D. H.; Nicolas, J. P.; Leuschen, C. (Copernicus Publications on behalf of the European Geosciences Union, 2014-07-31)
    In Antarctica, uncertainties in mass input and output translate directly into uncertainty in glacier mass balance and thus in sea level impact. While remotely sensed observations of ice velocity and thickness over the major ...
  • Constraints on the lake volume required for hydro-fracture through ice sheets 

    Krawczynski, Michael J.; Behn, Mark D.; Das, Sarah B.; Joughin, Ian (American Geophysical Union, 2009-05-16)
    Water-filled cracks are an effective mechanism to drive hydro-fractures through thick ice sheets. Crack geometry is therefore critical in assessing whether a supraglacial lake contains a sufficient volume of water to keep ...
  • Continued deceleration of Whillans Ice Stream, West Antarctica 

    Joughin, Ian; Bindschadler, R. A.; King, Matt A.; Voigt, D.; Alley, Richard B.; Anandakrishnan, S.; Horgan, H.; Peters, L.; Winberry, P.; Das, Sarah B.; Catania, Ginny (American Geophysical Union, 2005-11-17)
    Earlier observations indicated that Whillans Ice Stream slowed from 1973 to 1997. We collected new GPS observations of the ice stream's speed in 2003 and 2004. These data show that the ice stream is continuing to decelerate ...
  • Fracture propagation to the base of the Greenland Ice Sheet during supraglacial lake drainage 

    Das, Sarah B.; Joughin, Ian; Behn, Mark D.; Howat, Ian M.; King, Matt A.; Lizarralde, Daniel; Bhatia, Maya P. (2008-02-20)
    Surface meltwater that reaches the base of an ice sheet creates a mechanism for the rapid response of ice flow to climate change. The process whereby such a pathway is created through thick, cold ice has not, however, ...
  • Ice sheet record of recent sea-ice behavior and polynya variability in the Amundsen Sea, West Antarctica 

    Criscitiello, Alison S.; Das, Sarah B.; Evans, Matthew J.; Frey, Karen E.; Conway, Howard; Joughin, Ian; Medley, Brooke; Steig, Eric J. (John Wiley & Sons, 2013-01-25)
    Our understanding of past sea-ice variability is limited by the short length of satellite and instrumental records. Proxy records can extend these observations but require further development and validation. We compare ...
  • Influence of ice-sheet geometry and supraglacial lakes on seasonal ice-flow variability 

    Joughin, Ian; Das, Sarah B.; Flowers, G. E.; Behn, Mark D.; Alley, Richard B.; King, Matt A.; Smith, B. E.; Bamber, J. L.; van den Broeke, Michiel R.; van Angelen, J. H. (Copernicus Publications on behalf of the European Geosciences Union, 2013-07-26)
    Supraglacial lakes play an important role in establishing hydrological connections that allow lubricating seasonal meltwater to reach the base of the Greenland Ice Sheet. Here we use new surface velocity observations to ...
  • Limits to future expansion of surface-melt-enhanced ice flow into the interior of western Greenland 

    Poinar, Kristin; Joughin, Ian; Das, Sarah B.; Behn, Mark D.; Lenaerts, Jan T. M.; van den Broeke, Michiel R. (John Wiley & Sons, 2015-03-24)
    Moulins are important conduits for surface meltwater to reach the bed of the Greenland Ice Sheet. It has been proposed that in a warming climate, newly formed moulins associated with the inland migration of supraglacial ...
  • Seismicity on the western Greenland Ice Sheet : surface fracture in the vicinity of active moulins 

    Carmichael, Joshua D.; Joughin, Ian; Behn, Mark D.; Das, Sarah B.; King, Matt A.; Stevens, Laura; Lizarralde, Daniel (John Wiley & Sons, 2015-06-25)
    We analyzed geophone and GPS measurements collected within the ablation zone of the western Greenland Ice Sheet during a ~35 day period of the 2011 melt season to study changes in ice deformation before, during, and after ...
  • Tropical Pacific influence on the source and transport of marine aerosols to West Antarctica 

    Criscitiello, Alison S.; Das, Sarah B.; Karnauskas, Kristopher B.; Evans, Matthew J.; Frey, Karen E.; Joughin, Ian; Steig, Eric J.; McConnell, Joseph R.; Medley, Brooke (American Meteorological Society, 2014-02-01)
    The climate of West Antarctica is strongly influenced by remote forcing from the tropical Pacific. For example, recent surface warming over West Antarctica reflects atmospheric circulation changes over the Amundsen Sea, ...