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SUMMARY:ENAC Seminar Series by Dr. Poul Christoffersen
DTSTART:20181122T090000
DTEND:20181122T100000
DTSTAMP:20260427T221313Z
UID:d0cc796352de6506c150a240964e447bfe9e120713566936191b6d03
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr. Poul Christoffersen\n9:00 – 10:00 – Dr. Poul Christoff
 ersen\nReader in Glaciology\, Scott Polar Research Institute\, University 
 of Cambridge\n \nGlaciers in the 21st century: fast decline or complex re
 sponse?\n \nWith global temperatures rising by 0.2 °C per decade\, glaci
 al ice is increasingly lost in both alpine and polar environments. At pres
 ent\, 665 km3 of glacial ice is lost annually\, exposing more than a billi
 on people to increased flood risk. While the contemporary decline of glaci
 al ice masses is relatively well understood through satellite-derived meas
 urements\, there is a paucity of observations\, especially from the base o
 f glaciers\, which makes the theoretical approximation of their flow uncer
 tain. Predictions of future changes in glacial ice masses are consequently
  ambiguous.\nIn this talk\, I will present outcomes from the ERC-funded RE
 SPONDER research programme\, which addresses this knowledge gap with a ser
 ies of unique scientific experiments on Store Glacier in West Greenland. W
 e have discovered that UAV photogrammetry can identify basal hydrology thr
 ough uplift and velocity changes at the glacier’s surface\, and that sta
 tionary radar systems can capture ice deformation rates from to the daily 
 displacements of internal layers in the glacier. We have established daily
  records of basal melt rates\, which have never previously been measured o
 n glaciers\, and these rates were far higher than what energy balance calc
 ulations predict. Complementary to these experi-ments are time series of d
 ata generated by installing sensors in boreholes drilled to the base of th
 e glacier\, confirming that warm basal conditions prevail beneath very col
 d ice\, and pointing to a source of energy so far unaccounted for.\nThe da
 ta collected at Store Glacier are revealing processes not included in the 
 current genera-tion of numerical ice sheet models\, and we are using this 
 information to establish improved physical-ly-based formulations of glacia
 l processes\, thereby making numerical simulations of glacial ice masses m
 ore realistic. The latter is essential for accurate prediction of future r
 ates of global sea level rise in a warming world.
LOCATION:GC C3 30 https://plan.epfl.ch/?room=GCC330
STATUS:CONFIRMED
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