HR: 0800h
AN: C11A-0090    [Abstracts]
TI: How to Model Water Flow in Moulins?
AU: * Phillips, T P
EM: Thomas.Phillips@colorado.edu
AF: Cooperative Institute of Research in Environmental Sciences (CIRES), University of Colorado at Boulder CIRES Bldg., Rm. 318, Boulder, CO 80309-0216, United States
AU: Steffen, K
EM: konrad.steffen@colorado.edu
AF: Cooperative Institute of Research in Environmental Sciences (CIRES), University of Colorado at Boulder CIRES Bldg., Rm. 318, Boulder, CO 80309-0216, United States
AB: The development of large melt ponds on the Greenland Ice Sheet (GIS) and their drainage system indicate that moulins are a major contributor to the englacial water system. Here we review the current state of knowledge and the history of moulin research. In the late 19th century glaciologists led by Vallot climbed and studied the Grand Moulin on Mont Blanc. Despite being considered mystic due to their size and water drainage they have been studied by a few scientists such as Holmlund and Hooke (1980) or Puccini and Badino (1990). We develop a qualitative model of geometry as well as of the driving forces in the life cycle of moulins using data, photos, sketches, and climbing reports by ice speleologists and climbers. The GIS is temperate for the first 10 km at its margin and consists of cold ice further inland. The recent increase in melt water leads to an increase in basal water availability. The observed increase in ice velocity might be caused by the lubrication at the bed combined with a possible temperature rise in the cold part of the GIS. The raise of englacial water flow increases the volume of the conduits thus reducing the timing of water to reach the ice sheet bed. Our initial model starts with a narrow englacial non-arborescent channel network. We anticipate the development of the englacial hydrology system by using the 'Roethlisberger' conduit model. In addition we will show first model results on temperature fluctuations in the ice due to the hydrologic system.
DE: 0726 Ice sheets
DE: 0776 Glaciology (1621, 1827, 1863)
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting