BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:High resolution modelling of the seasonal evolution of surface wat
 er storage on the Greenland Ice Sheet - Dr Neil Arnold\, Scott Polar Reser
 ch Institute
DTSTART:20121003T153000Z
DTEND:20121003T163000Z
UID:TALK34003@talks.cam.ac.uk
CONTACT:Steven Palmer
DESCRIPTION:Seasonal meltwater lakes form when surface runoff gets trapped
  in topographic depressions on the surface of the Greenland Ice Sheet (GrI
 S) The development of such lakes affects the surface energy balance of the
  ice sheet\, (as the lower albedo of surface water increases radiation-dri
 ven melting)\, and the dynamics\, (as sudden drainage of such lakes has be
 en linked to observed increases in ice velocity). The areal extent and dep
 th of lakes has been inferred from satellite imagery of the ice sheet. How
 ever\, the lakes are transient features which often fill and drain during 
 the course of a melt-season\, meaning that estimates of potential surface 
 water storage from such studies are likely to be too small as it is unlike
 ly that all possible lakes will be observed. In this paper I present a dif
 ferent model-based strategy to estimate the seasonal potential surface wat
 er storage for a 2200 km2 area of the western Greenland Ice Sheet. The app
 roach combines a high resolution surface mass balance model (used to calcu
 late surface melt) with a novel model for supraglacial water routing which
  calculates the time-dependent filling of supraglacial lakes. The surface 
 melt model is driven by meteorological data collected at the GC-Net JAR 1 
 station\; the DEM for the melt model and the surface routing model is base
 d on high resolution ASTER Global Digital Elevation Model (GDEM2) data. La
 ke locations and filling rates are compared with observed lake volumes in 
 LANDSAT imagery for 2001 and 2005. For our study area\, there is a close a
 greement between the locations of observed lakes and modelled lakes. The m
 odel results shows a clear seasonal pattern of lakes progressively filling
  at higher elevations over the melt seasons. This study also shows that at
  least for the areas considered\, the GDEM2 data are of sufficient quality
  that 100 m scale surface features can be reliably identified\, suggesting
  that future high resolution modelling could make use of the GDEM data.
LOCATION:Scott Polar Research Institute\, main lecture theatre
END:VEVENT
END:VCALENDAR