Mixing and advection of a cold water cascade over the Wyville Thomson Ridge
The Wyville Thomson Ridge forms part of the barrier to the meridional Circulation across which cold Nordic Sea and Arctic water must traverse to reach the Atlantic Ocean. Overflow rates across the ridge are variable (but can be dramatic at times), and may provide a subtle indicator of significant ch...
Published in: | Deep Sea Research Part I: Oceanographic Research Papers |
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Main Authors: | , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2005
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Online Access: | https://pure.uhi.ac.uk/en/publications/e38091bb-ae6f-4560-94ca-43b166ef17f8 https://doi.org/10.1016/j.dsr.2005.03.002 |
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ftuhipublicatio:oai:pure.atira.dk:publications/e38091bb-ae6f-4560-94ca-43b166ef17f8 2024-02-04T09:58:40+01:00 Mixing and advection of a cold water cascade over the Wyville Thomson Ridge Sherwin, Toby Turrell, W.R. 2005 https://pure.uhi.ac.uk/en/publications/e38091bb-ae6f-4560-94ca-43b166ef17f8 https://doi.org/10.1016/j.dsr.2005.03.002 eng eng info:eu-repo/semantics/restrictedAccess Sherwin , T & Turrell , W R 2005 , ' Mixing and advection of a cold water cascade over the Wyville Thomson Ridge ' , DEEP-SEA RES PT I , no. 2 , pp. 1392-1413 . https://doi.org/10.1016/j.dsr.2005.03.002 LENGTH SCALES ROTATING FLUID SLOPING BOTTOM GRAVITY CURRENT DISSIPATION TURBULENCE DEEP-WATER OVERTURNS ROCKALL TROUGH Oceanography NORTH-ATLANTIC article 2005 ftuhipublicatio https://doi.org/10.1016/j.dsr.2005.03.002 2024-01-11T23:20:49Z The Wyville Thomson Ridge forms part of the barrier to the meridional Circulation across which cold Nordic Sea and Arctic water must traverse to reach the Atlantic Ocean. Overflow rates across the ridge are variable (but can be dramatic at times), and may provide a subtle indicator of significant change in the circulation in response to climate change. In spring 2003, a series of CTD sections were conducted during a large overflow event in which Norwegian Sea Deep Water (NSDW) cascaded down the southern side of the ridge into the Rockall Trough at a rate of between I and 2 Sv. The NSDW was partially mixed with overlying North Atlantic Water (NAW), and comprised about 1/3rd of the cascading water. The components of NAW and NSDW in the overflow were sufficiently large that there must have been a significant divergence of the inflow through the Faroe-Shetland Channel, and of the outflow through the Faroe Bank Channel. As the plume descended, its temperature near the sea bed warmed by over 3 degrees C in about a day. Although the slope was quite steep (0.03), the mean speed of the current (typically 0.36 m s(-1)) was too slow for significant entrainment of NAW to occur (the bulk Richardson number was of order 5). However, very large overturns (up to 50 m) were evident in some CTD profiles, and it is demonstrated from Thorpe scale estimates that the warming of the bottom waters was due to mixing within the plume. It is likely that some of the NSDW had mixed with NAW before it crossed the ridge. The overflow was trapped in a gully, which caused it to descend to great depth (1700 m) at a faster rate, and with less modification due to entrainment, than other overflows in the North Atlantic. The water that flowed into the northern part of the Rockall Trough had a temperature profile that ranged from about 3 to 8 degrees C. Water with a temperature of > 6 degrees C probably escaped into the Iceland Basin, between the banks that line the north-western part of the Trough. Colder water (<6 degrees C) must have ... Article in Journal/Newspaper Arctic Climate change Iceland Nordic Sea North Atlantic Norwegian Sea University of the Highlands and Islands: Research Database of UHI Arctic Faroe Bank ENVELOPE(-8.667,-8.667,60.917,60.917) Norwegian Sea Rockall Trough ENVELOPE(-15.036,-15.036,53.825,53.825) Wyville Thomson Ridge ENVELOPE(-7.500,-7.500,60.250,60.250) Wyville-Thomson Ridge ENVELOPE(-7.250,-7.250,60.000,60.000) Deep Sea Research Part I: Oceanographic Research Papers 52 8 1392 1413 |
institution |
Open Polar |
collection |
University of the Highlands and Islands: Research Database of UHI |
op_collection_id |
ftuhipublicatio |
language |
English |
topic |
LENGTH SCALES ROTATING FLUID SLOPING BOTTOM GRAVITY CURRENT DISSIPATION TURBULENCE DEEP-WATER OVERTURNS ROCKALL TROUGH Oceanography NORTH-ATLANTIC |
spellingShingle |
LENGTH SCALES ROTATING FLUID SLOPING BOTTOM GRAVITY CURRENT DISSIPATION TURBULENCE DEEP-WATER OVERTURNS ROCKALL TROUGH Oceanography NORTH-ATLANTIC Sherwin, Toby Turrell, W.R. Mixing and advection of a cold water cascade over the Wyville Thomson Ridge |
topic_facet |
LENGTH SCALES ROTATING FLUID SLOPING BOTTOM GRAVITY CURRENT DISSIPATION TURBULENCE DEEP-WATER OVERTURNS ROCKALL TROUGH Oceanography NORTH-ATLANTIC |
description |
The Wyville Thomson Ridge forms part of the barrier to the meridional Circulation across which cold Nordic Sea and Arctic water must traverse to reach the Atlantic Ocean. Overflow rates across the ridge are variable (but can be dramatic at times), and may provide a subtle indicator of significant change in the circulation in response to climate change. In spring 2003, a series of CTD sections were conducted during a large overflow event in which Norwegian Sea Deep Water (NSDW) cascaded down the southern side of the ridge into the Rockall Trough at a rate of between I and 2 Sv. The NSDW was partially mixed with overlying North Atlantic Water (NAW), and comprised about 1/3rd of the cascading water. The components of NAW and NSDW in the overflow were sufficiently large that there must have been a significant divergence of the inflow through the Faroe-Shetland Channel, and of the outflow through the Faroe Bank Channel. As the plume descended, its temperature near the sea bed warmed by over 3 degrees C in about a day. Although the slope was quite steep (0.03), the mean speed of the current (typically 0.36 m s(-1)) was too slow for significant entrainment of NAW to occur (the bulk Richardson number was of order 5). However, very large overturns (up to 50 m) were evident in some CTD profiles, and it is demonstrated from Thorpe scale estimates that the warming of the bottom waters was due to mixing within the plume. It is likely that some of the NSDW had mixed with NAW before it crossed the ridge. The overflow was trapped in a gully, which caused it to descend to great depth (1700 m) at a faster rate, and with less modification due to entrainment, than other overflows in the North Atlantic. The water that flowed into the northern part of the Rockall Trough had a temperature profile that ranged from about 3 to 8 degrees C. Water with a temperature of > 6 degrees C probably escaped into the Iceland Basin, between the banks that line the north-western part of the Trough. Colder water (<6 degrees C) must have ... |
format |
Article in Journal/Newspaper |
author |
Sherwin, Toby Turrell, W.R. |
author_facet |
Sherwin, Toby Turrell, W.R. |
author_sort |
Sherwin, Toby |
title |
Mixing and advection of a cold water cascade over the Wyville Thomson Ridge |
title_short |
Mixing and advection of a cold water cascade over the Wyville Thomson Ridge |
title_full |
Mixing and advection of a cold water cascade over the Wyville Thomson Ridge |
title_fullStr |
Mixing and advection of a cold water cascade over the Wyville Thomson Ridge |
title_full_unstemmed |
Mixing and advection of a cold water cascade over the Wyville Thomson Ridge |
title_sort |
mixing and advection of a cold water cascade over the wyville thomson ridge |
publishDate |
2005 |
url |
https://pure.uhi.ac.uk/en/publications/e38091bb-ae6f-4560-94ca-43b166ef17f8 https://doi.org/10.1016/j.dsr.2005.03.002 |
long_lat |
ENVELOPE(-8.667,-8.667,60.917,60.917) ENVELOPE(-15.036,-15.036,53.825,53.825) ENVELOPE(-7.500,-7.500,60.250,60.250) ENVELOPE(-7.250,-7.250,60.000,60.000) |
geographic |
Arctic Faroe Bank Norwegian Sea Rockall Trough Wyville Thomson Ridge Wyville-Thomson Ridge |
geographic_facet |
Arctic Faroe Bank Norwegian Sea Rockall Trough Wyville Thomson Ridge Wyville-Thomson Ridge |
genre |
Arctic Climate change Iceland Nordic Sea North Atlantic Norwegian Sea |
genre_facet |
Arctic Climate change Iceland Nordic Sea North Atlantic Norwegian Sea |
op_source |
Sherwin , T & Turrell , W R 2005 , ' Mixing and advection of a cold water cascade over the Wyville Thomson Ridge ' , DEEP-SEA RES PT I , no. 2 , pp. 1392-1413 . https://doi.org/10.1016/j.dsr.2005.03.002 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.dsr.2005.03.002 |
container_title |
Deep Sea Research Part I: Oceanographic Research Papers |
container_volume |
52 |
container_issue |
8 |
container_start_page |
1392 |
op_container_end_page |
1413 |
_version_ |
1789963142876364800 |