Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows

We study the annual patterns and linear trend of satellite sea level anomaly (SLA) over the southwest South Atlantic continental shelf (SWACS) between 54S and 36S. Results show that south of 42°S the thermal steric effect explains nearly 100% of the annual amplitude of the SLA, while north of 42°S i...

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Detalles Bibliográficos
Publicado: 2016
Materias:
annual cycle
continental shelf
sea level anomaly
amplitude
flow velocity
geostrophic flow
meridional circulation
river discharge
satellite imagery
sea level change
spatiotemporal analysis
trend analysis
wind stress
Atlantic Ocean
Atlantic Ocean (South)
Patagonian Shelf
Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_21699275_v121_n4_p2733_RuizEtcheverry
http://hdl.handle.net/20.500.12110/paper_21699275_v121_n4_p2733_RuizEtcheverry
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id paper:paper_21699275_v121_n4_p2733_RuizEtcheverry
record_format dspace
spelling paper:paper_21699275_v121_n4_p2733_RuizEtcheverry2023-06-08T16:34:39Z Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows annual cycle continental shelf sea level anomaly amplitude annual cycle continental shelf flow velocity geostrophic flow meridional circulation river discharge satellite imagery sea level change spatiotemporal analysis trend analysis wind stress Atlantic Ocean Atlantic Ocean (South) Patagonian Shelf We study the annual patterns and linear trend of satellite sea level anomaly (SLA) over the southwest South Atlantic continental shelf (SWACS) between 54S and 36S. Results show that south of 42°S the thermal steric effect explains nearly 100% of the annual amplitude of the SLA, while north of 42°S it explains less than 60%. This difference is due to the halosteric contribution. The annual wind variability plays a minor role over the whole continental shelf. The temporal linear trend in SLA ranges between 1 and 5 mm/yr (95% confidence level). The largest linear trends are found north of 39°S, at 42°S and at 50°S. We propose that in the northern region the large positive linear trends are associated with local changes in the density field caused by advective effects in response to a southward displacement of the South Atlantic High. The causes of the relative large SLA trends in two southern coastal regions are discussed as a function meridional wind stress and river discharge. Finally, we combined the annual cycle of SLA with the mean dynamic topography to estimate the absolute geostrophic velocities. This approach provides the first comprehensive description of the seasonal component of SWACS circulation based on satellite observations. The general circulation of the SWACS is northeastward with stronger/weaker geostrophic currents in austral summer/winter. At all latitudes, geostrophic velocities are larger (up to 20 cm/s) close to the shelf-break and decrease toward the coast. This spatio-temporal pattern is more intense north of 45°S. © 2016. American Geophysical Union. All Rights Reserved. 2016 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_21699275_v121_n4_p2733_RuizEtcheverry http://hdl.handle.net/20.500.12110/paper_21699275_v121_n4_p2733_RuizEtcheverry
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic annual cycle
continental shelf
sea level anomaly
amplitude
annual cycle
continental shelf
flow velocity
geostrophic flow
meridional circulation
river discharge
satellite imagery
sea level change
spatiotemporal analysis
trend analysis
wind stress
Atlantic Ocean
Atlantic Ocean (South)
Patagonian Shelf
spellingShingle annual cycle
continental shelf
sea level anomaly
amplitude
annual cycle
continental shelf
flow velocity
geostrophic flow
meridional circulation
river discharge
satellite imagery
sea level change
spatiotemporal analysis
trend analysis
wind stress
Atlantic Ocean
Atlantic Ocean (South)
Patagonian Shelf
Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows
topic_facet annual cycle
continental shelf
sea level anomaly
amplitude
annual cycle
continental shelf
flow velocity
geostrophic flow
meridional circulation
river discharge
satellite imagery
sea level change
spatiotemporal analysis
trend analysis
wind stress
Atlantic Ocean
Atlantic Ocean (South)
Patagonian Shelf
description We study the annual patterns and linear trend of satellite sea level anomaly (SLA) over the southwest South Atlantic continental shelf (SWACS) between 54S and 36S. Results show that south of 42°S the thermal steric effect explains nearly 100% of the annual amplitude of the SLA, while north of 42°S it explains less than 60%. This difference is due to the halosteric contribution. The annual wind variability plays a minor role over the whole continental shelf. The temporal linear trend in SLA ranges between 1 and 5 mm/yr (95% confidence level). The largest linear trends are found north of 39°S, at 42°S and at 50°S. We propose that in the northern region the large positive linear trends are associated with local changes in the density field caused by advective effects in response to a southward displacement of the South Atlantic High. The causes of the relative large SLA trends in two southern coastal regions are discussed as a function meridional wind stress and river discharge. Finally, we combined the annual cycle of SLA with the mean dynamic topography to estimate the absolute geostrophic velocities. This approach provides the first comprehensive description of the seasonal component of SWACS circulation based on satellite observations. The general circulation of the SWACS is northeastward with stronger/weaker geostrophic currents in austral summer/winter. At all latitudes, geostrophic velocities are larger (up to 20 cm/s) close to the shelf-break and decrease toward the coast. This spatio-temporal pattern is more intense north of 45°S. © 2016. American Geophysical Union. All Rights Reserved.
title Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows
title_short Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows
title_full Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows
title_fullStr Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows
title_full_unstemmed Sea level anomaly on the Patagonian continental shelf: Trends, annual patterns and geostrophic flows
title_sort sea level anomaly on the patagonian continental shelf: trends, annual patterns and geostrophic flows
publishDate 2016
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_21699275_v121_n4_p2733_RuizEtcheverry
http://hdl.handle.net/20.500.12110/paper_21699275_v121_n4_p2733_RuizEtcheverry
_version_ 1768542961756274688

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