SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0
<p>Subglacial hydrology has a strong influence on glacier and ice sheet dynamics, particularly through the dependence of sliding velocity on subglacial water pressure. Significant challenges are involved in modeling subglacial hydrology, as the drainage geometry and flow mechanics are cons...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-07-01
|
| Series: | Geoscientific Model Development |
| Online Access: | https://www.geosci-model-dev.net/11/2955/2018/gmd-11-2955-2018.pdf |
| Summary: | <p>Subglacial hydrology has a strong influence on glacier and ice
sheet dynamics, particularly through the dependence of sliding velocity on
subglacial water pressure. Significant challenges are involved in modeling
subglacial hydrology, as the drainage geometry and flow mechanics are
constantly changing, with complex feedbacks that play out between water and
ice. A clear tradition has been established in the subglacial hydrology
modeling literature of distinguishing between channelized (efficient) and
sheetlike (inefficient or distributed) drainage systems or components and
using slightly different forms of the governing equations in each subsystem
to represent the dominant physics. Specifically, many previous subglacial
hydrology models disregard opening by melt in the sheetlike system or
redistribute it to adjacent channel elements in order to avoid runaway
growth that occurs when it is included in the sheetlike system. We present a
new subglacial hydrology model, SHAKTI (Subglacial Hydrology and Kinetic,
Transient Interactions), in which a single set of governing equations is used
everywhere, including opening by melt in the entire domain. SHAKTI employs a
generalized relationship between the subglacial water flux and the hydraulic
gradient that allows for the representation of laminar, turbulent, and transitional
regimes depending on the local Reynolds number. This formulation allows for
the
coexistence of these flow regimes in different regions, and the configuration
and geometry of the subglacial system evolves naturally to represent
sheetlike drainage as well as systematic channelized drainage under
appropriate conditions. We present steady and transient example simulations
to illustrate the features and capabilities of the model and to examine
sensitivity to mesh size and time step size. The model is implemented as part
of the Ice Sheet System Model (ISSM).</p> |
|---|---|
| ISSN: | 1991-959X 1991-9603 |