Storm-driven across-shelf oceanic flows into coastal waters
The North Atlantic Ocean and northwest European shelf experience intense low-pressure systems during the winter months. The effect of strong winds on shelf circulation and water properties is poorly understood as observations during these episodes are rare, and key flow pathways have been poorly res...
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Online Access: | https://hdl.handle.net/10037/18541 https://doi.org/10.5194/os-16-389-2020 |
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ftunivtroemsoe:oai:munin.uit.no:10037/18541 2023-05-15T17:32:04+02:00 Storm-driven across-shelf oceanic flows into coastal waters Jones, Sam Inall, Mark Porter, Marie Graham, Jennifer A. Cottier, Finlo Robert 2020-04-02 https://hdl.handle.net/10037/18541 https://doi.org/10.5194/os-16-389-2020 eng eng European Geosciences Union (EGU) Ocean Science info:eu-repo/grantAgreement/EC/H2020/633211/EU/Optimizing and Enhancing the Integrated Atlantic Ocean Observing System/AtlantOS/ Jones S, Inall M, Porter, Graham, Cottier FR. Storm-driven across-shelf oceanic flows into coastal waters. Ocean Science. 2020;16(2):389-403 FRIDAID 1809264 doi:10.5194/os-16-389-2020 1812-0784 1812-0792 https://hdl.handle.net/10037/18541 openAccess Copyright 2020 The Author(s) VDP::Matematikk og Naturvitenskap: 400 Journal article Tidsskriftartikkel Peer reviewed publishedVersion 2020 ftunivtroemsoe https://doi.org/10.5194/os-16-389-2020 2021-06-25T17:57:31Z The North Atlantic Ocean and northwest European shelf experience intense low-pressure systems during the winter months. The effect of strong winds on shelf circulation and water properties is poorly understood as observations during these episodes are rare, and key flow pathways have been poorly resolved by models up to now. We compare the behaviour of a cross-shelf current in a quiescent period in late summer, with the same current sampled during a stormy period in midwinter, using drogued drifters. Concurrently, high-resolution time series of current speed and salinity from a coastal mooring are analysed. A Lagrangian analysis of modelled particle tracks is used to supplement the observations. Current speeds at 70 m during the summer transit are 10–20 cm s −1 , whereas on-shelf flow reaches 60 cm s −1 during the winter storm. The onset of high across-shelf flow is identified in the coastal mooring time series, both as an increase in coastal current speed and as an abrupt increase in salinity from 34.50 to 34.85, which lags the current by 8 d. We interpret this as the wind-driven advection of outer-shelf (near-oceanic) water towards the coastline, which represents a significant change from the coastal water pathways which typically feed the inner shelf. The modelled particle analysis supports this interpretation: particles which terminate in coastal waters are recruited locally during the late summer, but recruitment switches to the outer shelf during the winter storm. We estimate that during intense storm periods, on-shelf transport may be up to 0.48 Sv, but this is near the upper limit of transport based on the multi-year time series of coastal current and salinity. The likelihood of storms capable of producing these effects is much higher during positive North Atlantic Oscillation (NAO) winters. Article in Journal/Newspaper North Atlantic North Atlantic oscillation University of Tromsø: Munin Open Research Archive Midwinter ENVELOPE(139.931,139.931,-66.690,-66.690) Ocean Science 16 2 389 403 |
institution |
Open Polar |
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University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Matematikk og Naturvitenskap: 400 |
spellingShingle |
VDP::Matematikk og Naturvitenskap: 400 Jones, Sam Inall, Mark Porter, Marie Graham, Jennifer A. Cottier, Finlo Robert Storm-driven across-shelf oceanic flows into coastal waters |
topic_facet |
VDP::Matematikk og Naturvitenskap: 400 |
description |
The North Atlantic Ocean and northwest European shelf experience intense low-pressure systems during the winter months. The effect of strong winds on shelf circulation and water properties is poorly understood as observations during these episodes are rare, and key flow pathways have been poorly resolved by models up to now. We compare the behaviour of a cross-shelf current in a quiescent period in late summer, with the same current sampled during a stormy period in midwinter, using drogued drifters. Concurrently, high-resolution time series of current speed and salinity from a coastal mooring are analysed. A Lagrangian analysis of modelled particle tracks is used to supplement the observations. Current speeds at 70 m during the summer transit are 10–20 cm s −1 , whereas on-shelf flow reaches 60 cm s −1 during the winter storm. The onset of high across-shelf flow is identified in the coastal mooring time series, both as an increase in coastal current speed and as an abrupt increase in salinity from 34.50 to 34.85, which lags the current by 8 d. We interpret this as the wind-driven advection of outer-shelf (near-oceanic) water towards the coastline, which represents a significant change from the coastal water pathways which typically feed the inner shelf. The modelled particle analysis supports this interpretation: particles which terminate in coastal waters are recruited locally during the late summer, but recruitment switches to the outer shelf during the winter storm. We estimate that during intense storm periods, on-shelf transport may be up to 0.48 Sv, but this is near the upper limit of transport based on the multi-year time series of coastal current and salinity. The likelihood of storms capable of producing these effects is much higher during positive North Atlantic Oscillation (NAO) winters. |
format |
Article in Journal/Newspaper |
author |
Jones, Sam Inall, Mark Porter, Marie Graham, Jennifer A. Cottier, Finlo Robert |
author_facet |
Jones, Sam Inall, Mark Porter, Marie Graham, Jennifer A. Cottier, Finlo Robert |
author_sort |
Jones, Sam |
title |
Storm-driven across-shelf oceanic flows into coastal waters |
title_short |
Storm-driven across-shelf oceanic flows into coastal waters |
title_full |
Storm-driven across-shelf oceanic flows into coastal waters |
title_fullStr |
Storm-driven across-shelf oceanic flows into coastal waters |
title_full_unstemmed |
Storm-driven across-shelf oceanic flows into coastal waters |
title_sort |
storm-driven across-shelf oceanic flows into coastal waters |
publisher |
European Geosciences Union (EGU) |
publishDate |
2020 |
url |
https://hdl.handle.net/10037/18541 https://doi.org/10.5194/os-16-389-2020 |
long_lat |
ENVELOPE(139.931,139.931,-66.690,-66.690) |
geographic |
Midwinter |
geographic_facet |
Midwinter |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_relation |
Ocean Science info:eu-repo/grantAgreement/EC/H2020/633211/EU/Optimizing and Enhancing the Integrated Atlantic Ocean Observing System/AtlantOS/ Jones S, Inall M, Porter, Graham, Cottier FR. Storm-driven across-shelf oceanic flows into coastal waters. Ocean Science. 2020;16(2):389-403 FRIDAID 1809264 doi:10.5194/os-16-389-2020 1812-0784 1812-0792 https://hdl.handle.net/10037/18541 |
op_rights |
openAccess Copyright 2020 The Author(s) |
op_doi |
https://doi.org/10.5194/os-16-389-2020 |
container_title |
Ocean Science |
container_volume |
16 |
container_issue |
2 |
container_start_page |
389 |
op_container_end_page |
403 |
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1766129994034053120 |