Results from the Subglacial Hydrology Model Intercomparison Project (SHMIP)
Abstract
The SHMIP project is the first intercomparison project of subglacial drainage models (http://shmip.bitbucket.io). Its synthetic test suites and evaluation were designed such that any subglacial hydrology model producing effective pressure can participate. In contrast to ice deformation, the physical processes of subglacial hydrology (which in turn impacts basal sliding of glaciers) are poorly known. A further complication is that different glacial and geological settings can lead to different drainage physics. The aim of the project is therefore to qualitatively compare the outputs of the participating models for a wide range of water forcings and glacier geometries. This will allow to put existing studies, which use different drainage models, into context and will allow new studies to select the most suitable model for the problem at hand. We compare the results of the different models to the different experiments of the intercomparison project. Twelve models participated: eight 2D and four 1D models; nine include both an efficient and inefficient system, the other three one of the systems; all but two models use R-channels as efficient system, and/or a linked-cavity like inefficient system, one exception uses porous layers with different characteristic for each of the systems, the other exception is based on canals. The comparison is mainly based on the observation of effective pressures computed by the models. We observe large differences in this proxy with while keeping an overall similar behaviour to the different scenarios with a larger divergence for higher water inputs. These results show the importance of the choice of model approximation when implementing subglacial hydrology in an ice dynamic study as different effective pressure will lead to different velocity responses.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C44A..08D
- Keywords:
-
- 0720 Glaciers;
- CRYOSPHERE;
- 0726 Ice sheets;
- CRYOSPHERE;
- 0774 Dynamics;
- CRYOSPHERE;
- 0798 Modeling;
- CRYOSPHERE