The critical role of stratification in submarine channels: Implications for channelization and long runout of flows
The critical role of stratification in submarine channels: Implications for channelization and long runout of flows
Channelized submarine gravity currents travel remarkable distances, transporting sediment to the distal reaches of submarine fans. However, the mechanisms by which flows can be sustained over these distances remain enigmatic. In this paper we consider two shallow water models the first assumes the flow is unstratified whilst the second uses empirical models to describe vertical stratification, which effects depth averaged mass and momentum transfer. The importance of stratification is elucidated through comparison of modeled flow dynamics. It is found that the vertically stratified model shows the best fit to field data from a channelized field-scale gravity current in the Black Sea. Moreover, the stratified flow is confined by the channel to a much greater degree than the flow in the unstratified model. However, both models fail to accurately represent flow dynamics in the distal end of the system, suggesting current empirical stratification models require improvement to accurately describe field-scale gravity currents. It also highlights the limitations of weakly stratified small-scale experiments in describing field-scale processes. The results suggest that in real-world systems stratification is likely to enable maintenance of velocity and discharge within the channel, thus facilitating sediment suspension over distances of hundreds of kilometers on low seafloor gradients. This explains how flows can travel remarkable distances and transport their sediment to the distal parts of submarine fans.
stratification, density-driven flow
2620-2641
Dorrell, R.M.
2e8ebfe0-7987-4d2c-a92b-5d79b5135197
Darby, S.E.
ed29b739-9381-4928-a7d4-a0ca94815a90
Peakall, J.
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Sumner, E.J.
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Parsons, D.R.
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Wynn, R.B.
72ccd765-9240-45f8-9951-4552b497475a
April 2014
Dorrell, R.M.
2e8ebfe0-7987-4d2c-a92b-5d79b5135197
Darby, S.E.
ed29b739-9381-4928-a7d4-a0ca94815a90
Peakall, J.
2351dbf6-2c4f-4250-bacf-fe1b69870f26
Sumner, E.J.
dbba4b92-89cc-45d9-888e-d0e87e5c10ac
Parsons, D.R.
8bc551f4-ae49-48cd-8533-82a34e749d74
Wynn, R.B.
72ccd765-9240-45f8-9951-4552b497475a
Dorrell, R.M., Darby, S.E., Peakall, J., Sumner, E.J., Parsons, D.R. and Wynn, R.B.
(2014)
The critical role of stratification in submarine channels: Implications for channelization and long runout of flows.
Journal of Geophysical Research: Oceans, 119 (4), .
(doi:10.1002/2014JC009807).
Abstract
Channelized submarine gravity currents travel remarkable distances, transporting sediment to the distal reaches of submarine fans. However, the mechanisms by which flows can be sustained over these distances remain enigmatic. In this paper we consider two shallow water models the first assumes the flow is unstratified whilst the second uses empirical models to describe vertical stratification, which effects depth averaged mass and momentum transfer. The importance of stratification is elucidated through comparison of modeled flow dynamics. It is found that the vertically stratified model shows the best fit to field data from a channelized field-scale gravity current in the Black Sea. Moreover, the stratified flow is confined by the channel to a much greater degree than the flow in the unstratified model. However, both models fail to accurately represent flow dynamics in the distal end of the system, suggesting current empirical stratification models require improvement to accurately describe field-scale gravity currents. It also highlights the limitations of weakly stratified small-scale experiments in describing field-scale processes. The results suggest that in real-world systems stratification is likely to enable maintenance of velocity and discharge within the channel, thus facilitating sediment suspension over distances of hundreds of kilometers on low seafloor gradients. This explains how flows can travel remarkable distances and transport their sediment to the distal parts of submarine fans.
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e-pub ahead of print date: 22 April 2014
Published date: April 2014
Keywords:
stratification, density-driven flow
Organisations:
Marine Geoscience
Identifiers
Local EPrints ID: 364374
URI: http://eprints.soton.ac.uk/id/eprint/364374
ISSN: 2169-9275
PURE UUID: 978d471e-fb72-4e90-bd5f-bbd8961d43a0
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Date deposited: 23 Apr 2014 13:49
Last modified: 14 Mar 2024 16:34
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Author:
R.M. Dorrell
Author:
S.E. Darby
Author:
J. Peakall
Author:
D.R. Parsons
Author:
R.B. Wynn
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