The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System
The current study aims to analyse the vertical structure of the ocean during upwelling events using in situ and modelled data. Additionally, the influence of climate patterns, namely the North Atlantic Oscillation (NAO) and the East Atlantic (EA) pattern, on the vertical structure and their impact o...
Main Authors: | , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2022
|
Subjects: | |
Online Access: | https://doi.org/10.5194/egusphere-2022-702 https://noa.gwlb.de/receive/cop_mods_00062264 https://egusphere.copernicus.org/preprints/egusphere-2022-702/egusphere-2022-702.pdf |
id |
ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00062264 |
---|---|
record_format |
openpolar |
spelling |
ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00062264 2023-05-15T16:52:46+02:00 The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System Georg, Tina Neves, Maria Conceição Relvas, Paulo 2022-08 electronic https://doi.org/10.5194/egusphere-2022-702 https://noa.gwlb.de/receive/cop_mods_00062264 https://egusphere.copernicus.org/preprints/egusphere-2022-702/egusphere-2022-702.pdf eng eng Copernicus Publications https://doi.org/10.5194/egusphere-2022-702 https://noa.gwlb.de/receive/cop_mods_00062264 https://egusphere.copernicus.org/preprints/egusphere-2022-702/egusphere-2022-702.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2022 ftnonlinearchiv https://doi.org/10.5194/egusphere-2022-702 2022-08-14T23:11:52Z The current study aims to analyse the vertical structure of the ocean during upwelling events using in situ and modelled data. Additionally, the influence of climate patterns, namely the North Atlantic Oscillation (NAO) and the East Atlantic (EA) pattern, on the vertical structure and their impact on the upwelling activity is assessed for a period of 25 years (1993–2017). The study focuses on the central part of the Canary Current (25–35° N) with persistent upwelling throughout the year with an annual cycle and strongest events from June to September. Upwelling is determined using three different approaches: One index is calculated based on temperature differences between the coastal and the offshore area and two based on wind data and the resulting Ekman transport. Different data sets were chosen according to the indices. Stable coastal upwelling can be observed in the study area for the analysed time span with differences throughout the latitudes and a time lag of four to five months between the wind and the temperature-based indices. A deepening of the isothermal layer depth and a cooling of temperatures is observed in the vertical structure of coastal waters representing a deeper mixing of the ocean and the rise of cooler, denser water towards the surface. During years of a positive NAO, corresponding to a strengthening of the Azores High and the Iceland Low, stronger winds lead to an intensification of the upwelling activity, an enhanced mixing of the upper ocean and a deeper (shallower) isothermal layer along the coast (offshore). The opposite is observed in years of negative NAO. Both effects are enhanced in years with a coupled, opposite phase of the EA pattern and are mainly visible during winter months where the effect of both indices is the greatest. The study therefore suggests stronger upwelling activities in winters of positive North Atlantic Oscillation coupled with a negative East Atlantic pattern and emphasizes the importance of interactions between the climate patterns and upwelling. Article in Journal/Newspaper Iceland North Atlantic North Atlantic oscillation Niedersächsisches Online-Archiv NOA |
institution |
Open Polar |
collection |
Niedersächsisches Online-Archiv NOA |
op_collection_id |
ftnonlinearchiv |
language |
English |
topic |
article Verlagsveröffentlichung |
spellingShingle |
article Verlagsveröffentlichung Georg, Tina Neves, Maria Conceição Relvas, Paulo The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System |
topic_facet |
article Verlagsveröffentlichung |
description |
The current study aims to analyse the vertical structure of the ocean during upwelling events using in situ and modelled data. Additionally, the influence of climate patterns, namely the North Atlantic Oscillation (NAO) and the East Atlantic (EA) pattern, on the vertical structure and their impact on the upwelling activity is assessed for a period of 25 years (1993–2017). The study focuses on the central part of the Canary Current (25–35° N) with persistent upwelling throughout the year with an annual cycle and strongest events from June to September. Upwelling is determined using three different approaches: One index is calculated based on temperature differences between the coastal and the offshore area and two based on wind data and the resulting Ekman transport. Different data sets were chosen according to the indices. Stable coastal upwelling can be observed in the study area for the analysed time span with differences throughout the latitudes and a time lag of four to five months between the wind and the temperature-based indices. A deepening of the isothermal layer depth and a cooling of temperatures is observed in the vertical structure of coastal waters representing a deeper mixing of the ocean and the rise of cooler, denser water towards the surface. During years of a positive NAO, corresponding to a strengthening of the Azores High and the Iceland Low, stronger winds lead to an intensification of the upwelling activity, an enhanced mixing of the upper ocean and a deeper (shallower) isothermal layer along the coast (offshore). The opposite is observed in years of negative NAO. Both effects are enhanced in years with a coupled, opposite phase of the EA pattern and are mainly visible during winter months where the effect of both indices is the greatest. The study therefore suggests stronger upwelling activities in winters of positive North Atlantic Oscillation coupled with a negative East Atlantic pattern and emphasizes the importance of interactions between the climate patterns and upwelling. |
format |
Article in Journal/Newspaper |
author |
Georg, Tina Neves, Maria Conceição Relvas, Paulo |
author_facet |
Georg, Tina Neves, Maria Conceição Relvas, Paulo |
author_sort |
Georg, Tina |
title |
The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System |
title_short |
The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System |
title_full |
The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System |
title_fullStr |
The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System |
title_full_unstemmed |
The signature of NAO and EA climate patterns on the vertical structure of the Canary Current Upwelling System |
title_sort |
signature of nao and ea climate patterns on the vertical structure of the canary current upwelling system |
publisher |
Copernicus Publications |
publishDate |
2022 |
url |
https://doi.org/10.5194/egusphere-2022-702 https://noa.gwlb.de/receive/cop_mods_00062264 https://egusphere.copernicus.org/preprints/egusphere-2022-702/egusphere-2022-702.pdf |
genre |
Iceland North Atlantic North Atlantic oscillation |
genre_facet |
Iceland North Atlantic North Atlantic oscillation |
op_relation |
https://doi.org/10.5194/egusphere-2022-702 https://noa.gwlb.de/receive/cop_mods_00062264 https://egusphere.copernicus.org/preprints/egusphere-2022-702/egusphere-2022-702.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/restrictedAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/egusphere-2022-702 |
_version_ |
1766043149844611072 |