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SUMMARY:Double bill: Modelling the evolution of supra-glacial lakes in the
  Russell glacier region of the Greenland Ice Sheet / IMBIE - Ice sheet Mas
 s Balance Inter-comparison Exercise - Amber Leeson &amp\; Dr Kate Briggs\,
  School of Earth &amp\; Environment\, University of Leeds
DTSTART:20120606T153000Z
DTEND:20120606T163000Z
UID:TALK38339@talks.cam.ac.uk
CONTACT:Steven Palmer
DESCRIPTION:_Modelling the evolution of supra-glacial lakes in the Russell
  glacier region of the Greenland Ice Sheet_\n\nWe present a new 2 dimensio
 nal model of supra-glacial lake evolution at the western Greenland ice she
 et margin which uses a digital elevation model (DEM) to route meltwater ru
 noff simulated by the regional climate model MAR (Modele Atmospherique Reg
 ional) across the ice sheet surface.  The resulting water drainage network
  and supra-glacial lake distribution are compared to optical satellite ima
 gery derived from the MODIS satellite.  Our simulations of lake evolution 
 in 2003-2007 confirm that the locations of supra-glacial lakes coincide wi
 th intransient depressions in the ice surface topography\, and that the on
 set date of lakes coincides with local runoff availability.  We also attem
 pt to constrain a practical limit to the area occupied by modelled supra-g
 lacial lakes (6 %) in our simulation and volume which they contain (12% al
 l runoff produced) which is not exceeded\, even when double the estimated 
 runoff amount is supplied.\n\n_IMBIE - Ice sheet Mass Balance Inter-compar
 ison Exercise_\n\nAccurate monitoring of ice sheet mass balance is critica
 l for understanding the interaction of climate and ice sheets\, and for fo
 recasting sea level rise. Over the past 20 years or so the measurement of 
 ice sheet mass balance has been revolutionised by the advent of three geod
 etic techniques- altimetry\, gravimetry and the mass budget method. There 
 are now more than 30 published results of mass balance for the Greenland a
 nd Antarctica Ice Sheets. However\, disagreements between many of the publ
 ished results have limited the confidence in the measurements. Over the pa
 st year\, a group of over 30 scientists have worked together on the IMBIE 
 project with the aim of understanding the causes for these disagreements a
 nd reconciling the measurements of ice sheet mass balance from the differe
 nt geodetic techniques. In my presentation\, I will outline the approach a
 nd experiments of the IMBIE group\, and some of our key findings.\n
LOCATION:Scott Polar Research Institute\, main lecture theatre
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