Observations of the South Atlantic Subtropical Mode Water using PIES data

Detalhes bibliográficos
Autor(a) principal: Cortezi, Matheus Vasconcellos
Data de Publicação: 2017
Tipo de documento: Dissertação
Idioma: eng
Título da fonte: Biblioteca Digital de Teses e Dissertações da USP
Texto Completo: http://www.teses.usp.br/teses/disponiveis/21/21135/tde-23032018-141954/
Resumo: Subtropical mode water is a voluminous body of water in the ocean whose main feature is the homogeneity in both vertical structure and horizontal extension. The subtropical mode water (STMW) of the southwest Atlantic is formed between the months of July and October near the Brazil-Malvinas confluence and along the Brazil Current recirculation gyre. The formation region extends on the order of 3000 km zonally, from 20°W to 50°W, and 1000 km meridionally, from 30°S to 40°S, and it is typically about 170 m thick. In situ data from pressure-equipped inverted echo sounders (PIES) installed in the western portion of the basin, along 34.5°S, are available from 2009 to the present. These data after processed and calibrated can provide an unprecedented description of the STMW involving processes since its formation at the surface until the final stage of its residence in the interior of the ocean. Temperature and salinity data estimated by the PIES are based on empirical look-up tables that relate the acoustic travel time with the baroclinic structure of the ocean. This technique is known as the Gravest Empirical Mode (GEM), and here it is used to detect profiles containing homogeneous segments of temperature and salinity that characterize the mode water. The GEM method was seasonally corrected to reconstruct surface variability necessary for STMW formation. The interannual covariance between STMW layer thickness and the Brazil Current was calculated, but no significant correlation at that time scale was observed. The mode water layer detected was about 220 m ± 55 m thick on all sites, agreeing with previous studies.
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spelling Observations of the South Atlantic Subtropical Mode Water using PIES dataObservações da Água Modal Subtropical Sul utilizando dados PIESÁgua modal subtropicalBrazil CurrentCorrente do Brasilecossonda invertidaGEMGEMGraves Empirical Modeinverted echo soundersPIESPIESSouth AtlanticSubtropical mode waterSubtropical mode water is a voluminous body of water in the ocean whose main feature is the homogeneity in both vertical structure and horizontal extension. The subtropical mode water (STMW) of the southwest Atlantic is formed between the months of July and October near the Brazil-Malvinas confluence and along the Brazil Current recirculation gyre. The formation region extends on the order of 3000 km zonally, from 20°W to 50°W, and 1000 km meridionally, from 30°S to 40°S, and it is typically about 170 m thick. In situ data from pressure-equipped inverted echo sounders (PIES) installed in the western portion of the basin, along 34.5°S, are available from 2009 to the present. These data after processed and calibrated can provide an unprecedented description of the STMW involving processes since its formation at the surface until the final stage of its residence in the interior of the ocean. Temperature and salinity data estimated by the PIES are based on empirical look-up tables that relate the acoustic travel time with the baroclinic structure of the ocean. This technique is known as the Gravest Empirical Mode (GEM), and here it is used to detect profiles containing homogeneous segments of temperature and salinity that characterize the mode water. The GEM method was seasonally corrected to reconstruct surface variability necessary for STMW formation. The interannual covariance between STMW layer thickness and the Brazil Current was calculated, but no significant correlation at that time scale was observed. The mode water layer detected was about 220 m ± 55 m thick on all sites, agreeing with previous studies.A água modal subtropical é um grande volume de água no oceano cuja característica principal é a homogeneidade nas estruturas vertical e horizontal. A água modal subtropical do sudoeste do Atlântico é formada entre os meses de julho e outubro perto da confluência Brasil-Malvinas e ao longo da recirculação da Corrente do Brasil. A região de formação se estende na ordem de 3000 km zonalmente, de 20°W a 50°W e 1000 km meridionalmente, de 30°S a 40°S, e tipicamente tem cerca de 170 m de espessura. Dados in situ de ecossondas invertidas com sensor de pressão (PIES) instaladas na porção ocidental da bacia, ao longo de 34,5°S, estão disponíveis a partir de 2009 até o presente. Estes dados após o processamento e calibração podem fornecer uma descrição sem precedentes da Água Modal Subtropical do Atlântico Sul envolvendo processos desde sua formação na superfície até o estágio final de sua permanência no interior do oceano. Os dados de temperatura e salinidade estimados pelos PIES são baseados em tabelas de referência (look-up tables) que relacionam o tempo de retorno do sinal acústico com a estrutura baroclínica do oceano. Esta técnica é conhecida como o Gravest Empirical Mode (GEM),e aqui é usado para detectar perfis contendo segmentos homogêneos de temperatura e salinidade que caracterizam a água modal. Foi aplicada uma correção sazonal ao método GEM para reconstruir a variabilidade da superfície necessária para a formação STMW. A covariância interanual entre a espessura da camada STMW e a corrente do Brasil foi calculada, mas não foi observada correlação significativa naquela escala de tempo. A camada de água em modo detectada foi de cerca de 220 m ± 55 m de espessura em todos os sites, concordando com estudos prévios.Biblioteca Digitais de Teses e Dissertações da USPSato, Olga TiemiCortezi, Matheus Vasconcellos2017-08-18info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisapplication/pdfhttp://www.teses.usp.br/teses/disponiveis/21/21135/tde-23032018-141954/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2018-07-19T20:50:39Zoai:teses.usp.br:tde-23032018-141954Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212018-07-19T20:50:39Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false
dc.title.none.fl_str_mv Observations of the South Atlantic Subtropical Mode Water using PIES data
Observações da Água Modal Subtropical Sul utilizando dados PIES
title Observations of the South Atlantic Subtropical Mode Water using PIES data
spellingShingle Observations of the South Atlantic Subtropical Mode Water using PIES data
Cortezi, Matheus Vasconcellos
Água modal subtropical
Brazil Current
Corrente do Brasil
ecossonda invertida
GEM
GEM
Graves Empirical Mode
inverted echo sounders
PIES
PIES
South Atlantic
Subtropical mode water
title_short Observations of the South Atlantic Subtropical Mode Water using PIES data
title_full Observations of the South Atlantic Subtropical Mode Water using PIES data
title_fullStr Observations of the South Atlantic Subtropical Mode Water using PIES data
title_full_unstemmed Observations of the South Atlantic Subtropical Mode Water using PIES data
title_sort Observations of the South Atlantic Subtropical Mode Water using PIES data
author Cortezi, Matheus Vasconcellos
author_facet Cortezi, Matheus Vasconcellos
author_role author
dc.contributor.none.fl_str_mv Sato, Olga Tiemi
dc.contributor.author.fl_str_mv Cortezi, Matheus Vasconcellos
dc.subject.por.fl_str_mv Água modal subtropical
Brazil Current
Corrente do Brasil
ecossonda invertida
GEM
GEM
Graves Empirical Mode
inverted echo sounders
PIES
PIES
South Atlantic
Subtropical mode water
topic Água modal subtropical
Brazil Current
Corrente do Brasil
ecossonda invertida
GEM
GEM
Graves Empirical Mode
inverted echo sounders
PIES
PIES
South Atlantic
Subtropical mode water
description Subtropical mode water is a voluminous body of water in the ocean whose main feature is the homogeneity in both vertical structure and horizontal extension. The subtropical mode water (STMW) of the southwest Atlantic is formed between the months of July and October near the Brazil-Malvinas confluence and along the Brazil Current recirculation gyre. The formation region extends on the order of 3000 km zonally, from 20°W to 50°W, and 1000 km meridionally, from 30°S to 40°S, and it is typically about 170 m thick. In situ data from pressure-equipped inverted echo sounders (PIES) installed in the western portion of the basin, along 34.5°S, are available from 2009 to the present. These data after processed and calibrated can provide an unprecedented description of the STMW involving processes since its formation at the surface until the final stage of its residence in the interior of the ocean. Temperature and salinity data estimated by the PIES are based on empirical look-up tables that relate the acoustic travel time with the baroclinic structure of the ocean. This technique is known as the Gravest Empirical Mode (GEM), and here it is used to detect profiles containing homogeneous segments of temperature and salinity that characterize the mode water. The GEM method was seasonally corrected to reconstruct surface variability necessary for STMW formation. The interannual covariance between STMW layer thickness and the Brazil Current was calculated, but no significant correlation at that time scale was observed. The mode water layer detected was about 220 m ± 55 m thick on all sites, agreeing with previous studies.
publishDate 2017
dc.date.none.fl_str_mv 2017-08-18
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/masterThesis
format masterThesis
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dc.identifier.uri.fl_str_mv http://www.teses.usp.br/teses/disponiveis/21/21135/tde-23032018-141954/
url http://www.teses.usp.br/teses/disponiveis/21/21135/tde-23032018-141954/
dc.language.iso.fl_str_mv eng
language eng
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dc.rights.driver.fl_str_mv Liberar o conteúdo para acesso público.
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Liberar o conteúdo para acesso público.
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
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dc.publisher.none.fl_str_mv Biblioteca Digitais de Teses e Dissertações da USP
publisher.none.fl_str_mv Biblioteca Digitais de Teses e Dissertações da USP
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reponame:Biblioteca Digital de Teses e Dissertações da USP
instname:Universidade de São Paulo (USP)
instacron:USP
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institution USP
reponame_str Biblioteca Digital de Teses e Dissertações da USP
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