SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0
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 changi...
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ftcopernicus:oai:publications.copernicus.org:gmd66949 2023-05-15T16:40:43+02:00 SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 Sommers, Aleah Rajaram, Harihar Morlighem, Mathieu 2019-01-21 application/pdf https://doi.org/10.5194/gmd-11-2955-2018 https://gmd.copernicus.org/articles/11/2955/2018/ eng eng doi:10.5194/gmd-11-2955-2018 https://gmd.copernicus.org/articles/11/2955/2018/ eISSN: 1991-9603 Text 2019 ftcopernicus https://doi.org/10.5194/gmd-11-2955-2018 2020-07-20T16:23:12Z 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). Text Ice Sheet Copernicus Publications: E-Journals Geoscientific Model Development 11 7 2955 2974 |
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Copernicus Publications: E-Journals |
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English |
description |
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). |
format |
Text |
author |
Sommers, Aleah Rajaram, Harihar Morlighem, Mathieu |
spellingShingle |
Sommers, Aleah Rajaram, Harihar Morlighem, Mathieu SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 |
author_facet |
Sommers, Aleah Rajaram, Harihar Morlighem, Mathieu |
author_sort |
Sommers, Aleah |
title |
SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 |
title_short |
SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 |
title_full |
SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 |
title_fullStr |
SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 |
title_full_unstemmed |
SHAKTI: Subglacial Hydrology and Kinetic, Transient Interactions v1.0 |
title_sort |
shakti: subglacial hydrology and kinetic, transient interactions v1.0 |
publishDate |
2019 |
url |
https://doi.org/10.5194/gmd-11-2955-2018 https://gmd.copernicus.org/articles/11/2955/2018/ |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
eISSN: 1991-9603 |
op_relation |
doi:10.5194/gmd-11-2955-2018 https://gmd.copernicus.org/articles/11/2955/2018/ |
op_doi |
https://doi.org/10.5194/gmd-11-2955-2018 |
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Geoscientific Model Development |
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11 |
container_issue |
7 |
container_start_page |
2955 |
op_container_end_page |
2974 |
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1766031124643971072 |