Este trabalho apresenta uma investigação da interação entre o gelo marinho Antártico e o setor austral e sudoeste do Atlântico Sul. Para realizar este estudo foram utilizados dados de satélite da concentração do gelo marinho e o modelo numérico acoplado do NCAR (Nacional Center for Atmospheric Research) o CCSM3 (Community Climate System Model) versão 3. O CCSM3 foi integrado por 150 anos em 3 diferentes simulações. Estas foram forçadas com as climatologias prescritas da concentração de gelo máximo (MAX), mínimo (MIN) e médio (controle) com o objetivo de avaliar o impacto das mudanças do gelo marinho Antártico no Mar de Weddell e na região da Confluência Brasil-Malvinas (CBM). Este estudo enfatiza a interação das escalas de tempo anual, interanual a decadal. A metodologia empregada nesta pesquisa inclue as análises de correlação e espectral, bem como as técnicas estatísticas de funções ortogonais empíricas (EOF) e decomposição de valores singulares (SVD). O comportamento climático das variáveis oceânicas apresentou sensibilidade às diferentes concentrações de gelo marinho Antártico. A variabilidade das anomalias de TSM e SSM mostraram para o experimento MIN padrões espaciais que caracterizam um regime frio do Giro de Weddell, associado a menor intrusão da CDW. A resposta da variabilidade da temperatura, entre os cenários de gelo MAX e MIN, para a região da CBM sugere que menores concentrações de gelo marinho Antártico intensificam as anomalias de TSM desta região, com periodicidade interanual de 2-3 anos e decadal de 25 anos. A circulação oceânica, em ambas as regiões analisadas, associada a fase positiva da SAM se intensifica devido a influência das menores concentrações de gelo marinho. / In this work the interaction between Antarctic sea-ice and the South Atlantic ocean (austral and southwestern sectors) is investigated. To accomplish this satellite-observed sea-ice concentration (SIC) and a coupled model from NCAR-CCSM3 (National Center for Atmospheric Research - Community Climate System Model version 3) were employed. Three 150-year simulations, one each with the maximum (MAX), minimum (MIN) and average (control) SIC prescribed climatologies, were used to drive the CCSM3 run. The goal of the research is to evaluate the Weddell Sea and Brazil-Malvinas confluence (BMC) response to observed extremes in Antarctic sea-ice. This study focuses on annual, interannual and decadal timescales. The applied methodology uses correlation and spectrum analyses, as well as Empirical Orthogonal Functions (EOF) and Singular Value Decomposition (SVD). The annual mean behavior of oceanic variables showed sensibility to Antarctic sea-ice changes. The variability of SST and SSS anomalies showed for the sea-ice MIN experiment a spatial pattern that characterizes the cold regime of the Weddell Gyre, associate with low CDW intrusion. The response of the temperature variability, between sea-ice MAX and MIN scenarios, for the BMC region suggests that less Antarctic sea-ice produces a SST anomaly intensification in this region with a interannual cycle of the 2-3year and decadal cycle of the 25-year. The oceanic circulation in both study regions, related to positive SAM events, showed a intensification to less SIC influence.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-11-08T17:53:03Z No. of bitstreams: 1 2016 - Israel de S? Maciel.pdf: 3184590 bytes, checksum: 1d079e88bc7d2ff9256dc558436b7cd3 (MD5) / Made available in DSpace on 2017-11-08T17:53:03Z (GMT). No. of bitstreams: 1 2016 - Israel de S? Maciel.pdf: 3184590 bytes, checksum: 1d079e88bc7d2ff9256dc558436b7cd3 (MD5) Previous issue date: 2016-02-02 / CAPES / Pinnipeds produce a variety of underwater sounds that are often related to reproductive activities and social interactions. In addition, several species of seals provide evidence of vocalizations with geographical and individual variations. Most of bioacoustics researches with seals studied the terrestrial environment repertoire using linear analysis. However, some characteristics of vocalizations can not be explained with linear analysis only or taking into account only one part of the animal's life. The nonlinear phenomena (NLP) present in vocalizations (sideband, harmonic, sub-harmonic, biphonation, jump of frequency and deterministic chaos) are still poorly studied. Given the importance of this phenomena in vocalizations to individual recognition, especially in social mammals, was studied the underwater vocalizations of Antarctic seals in order to know their vocal repertoire and their NLP as well as discuss their possible function. In 2013, Brazilian Navy conducted acoustic recordings on Half Moon Island. In this collection were recorded 128GB of sound files between 12th and 30th of November. A total of 18 days of uninterrupted collections, producing 7,448 files of 3 minutes each. These recordings were taken at the presence of seals to Lobodontini Tribe. A total of 15 types of vocalizations were found in the period between days 12-16/November. A pattern in the vocalizations types L, K and E, arranged in sequence K, L and E, respectively, was observed in all seal recordings. All files presented biphonations, jumps of frequency, harmonics, sidebands and chaos in nine types of vocalizations (A, C, E, F, K, L, M, N and O). The nonlinearities were abundant on all files, being present in 75.56% (N = 1829) of vocalizations. Deterministic chaos was most common, present in 53.86% of non-linear features and 43.08% of vocalizations in general. Taking into account only the tonal vocalizations, 88.85% of vocalizations were nonlinear. The repetition of the KLE pattern also displays a recognition function. The NLP, mainly deterministic chaos, had high incidence in the studied vocalizations indicating that this type has an important role in communication. Furthermore, it seems to belong to the acoustic pattern of Antarctic?s Lobodontines. / Pin?pedes produzem uma variedade de sons subaqu?ticos que frequentemente s?o relacionados com atividades reprodutivas e intera??es sociais. Diversas esp?cies de focas apresentam evid?ncias de vocaliza??es com varia??es geogr?ficas e individuais. A maioria dos trabalhos com focas estudou o repert?rio em ambiente terrestre e com olhares para as an?lises lineares. Entretanto, algumas caracter?sticas das vocaliza??es n?o podem ser explicadas apenas com an?lises lineares ou levando em conta apenas uma parte da vida do animal. Os fen?menos n?o lineares (FNLs) presentes em vocaliza??es (banda lateral, harm?nico, sub-harm?nico, bifona??o, pulos de frequ?ncia e caos determin?stico) ainda s?o pouco estudados. Dada a import?ncia deste fen?meno nas vocaliza??es para o reconhecimento individual, principalmente em mam?feros sociais, este trabalho buscou estudar as vocaliza??es subaqu?ticas de focas ant?rticas, visando conhecer seu repert?rio vocal e seus FNLs, bem como discutir a poss?vel fun??o dos mesmos. Em 2013, a Marinha do Brasil realizou grava??es ac?sticas na Ilha Meia Lua na Ant?rtica. Nesta coleta foram registrados 128GB de arquivos de som nos dias entre 12 e 30 de novembro, totalizando 7.448 arquivos de 3 minutos cada. Nestas grava??es foi constatada a presen?a de focas pertencentes ? Tribo Lobodontini. Contatou-se tamb?m a presen?a de 15 tipos de vocaliza??es no per?odo entre os dias 12 a 16/novembro. Em todos os dias que houve grava??es de focas foi observado um padr?o nos tipos L, K e E, organizados na sequ?ncia K, L e E, respectivamente. Ap?s a inspe??o visual de todos os arquivos, foram encontrados pulos de frequ?ncia, bifona??es, harm?nicos, bandas laterais e caos determin?stico em nove tipos de vocaliza??es (A, C, E, F, K, L, M, N e O). As n?o linearidades foram abundantes em todos os arquivos, estando presentes em 75,56% (N=1829) das vocaliza??es. O caos determin?stico foi o mais comumente observado, estando presente em 53,86% das fei??es n?o lineares e 43,08% das vocaliza??es em geral. Levando em conta apenas as vocaliza??es tonais, 88,85% das vocaliza??es foram n?o lineares. A repeti??o do padr?o KLE parece apresentar uma fun??o de reconhecimento. Os FNLs, principalmente os do tipo caos determin?stico, estiveram muito presentes nas vocaliza??es estudadas, indicando que este tipo de emiss?o possui uma fun??o importante na comunica??o. Al?m disso, estes parecem pertencer ao repert?rio ac?stico padr?o de Lobodontines ant?rticos.

Este trabalho apresenta uma investigação da interação entre o gelo marinho Antártico e o setor austral e sudoeste do Atlântico Sul. Para realizar este estudo foram utilizados dados de satélite da concentração do gelo marinho e o modelo numérico acoplado do NCAR (Nacional Center for Atmospheric Research) o CCSM3 (Community Climate System Model) versão 3. O CCSM3 foi integrado por 150 anos em 3 diferentes simulações. Estas foram forçadas com as climatologias prescritas da concentração de gelo máximo (MAX), mínimo (MIN) e médio (controle) com o objetivo de avaliar o impacto das mudanças do gelo marinho Antártico no Mar de Weddell e na região da Confluência Brasil-Malvinas (CBM). Este estudo enfatiza a interação das escalas de tempo anual, interanual a decadal. A metodologia empregada nesta pesquisa inclue as análises de correlação e espectral, bem como as técnicas estatísticas de funções ortogonais empíricas (EOF) e decomposição de valores singulares (SVD). O comportamento climático das variáveis oceânicas apresentou sensibilidade às diferentes concentrações de gelo marinho Antártico. A variabilidade das anomalias de TSM e SSM mostraram para o experimento MIN padrões espaciais que caracterizam um regime frio do Giro de Weddell, associado a menor intrusão da CDW. A resposta da variabilidade da temperatura, entre os cenários de gelo MAX e MIN, para a região da CBM sugere que menores concentrações de gelo marinho Antártico intensificam as anomalias de TSM desta região, com periodicidade interanual de 2-3 anos e decadal de 25 anos. A circulação oceânica, em ambas as regiões analisadas, associada a fase positiva da SAM se intensifica devido a influência das menores concentrações de gelo marinho. / In this work the interaction between Antarctic sea-ice and the South Atlantic ocean (austral and southwestern sectors) is investigated. To accomplish this satellite-observed sea-ice concentration (SIC) and a coupled model from NCAR-CCSM3 (National Center for Atmospheric Research - Community Climate System Model version 3) were employed. Three 150-year simulations, one each with the maximum (MAX), minimum (MIN) and average (control) SIC prescribed climatologies, were used to drive the CCSM3 run. The goal of the research is to evaluate the Weddell Sea and Brazil-Malvinas confluence (BMC) response to observed extremes in Antarctic sea-ice. This study focuses on annual, interannual and decadal timescales. The applied methodology uses correlation and spectrum analyses, as well as Empirical Orthogonal Functions (EOF) and Singular Value Decomposition (SVD). The annual mean behavior of oceanic variables showed sensibility to Antarctic sea-ice changes. The variability of SST and SSS anomalies showed for the sea-ice MIN experiment a spatial pattern that characterizes the cold regime of the Weddell Gyre, associate with low CDW intrusion. The response of the temperature variability, between sea-ice MAX and MIN scenarios, for the BMC region suggests that less Antarctic sea-ice produces a SST anomaly intensification in this region with a interannual cycle of the 2-3year and decadal cycle of the 25-year. The oceanic circulation in both study regions, related to positive SAM events, showed a intensification to less SIC influence.

Dans cette thèse, nous étudions la dynamique du plateau antarctique à l'aide d'observations in situ. Nous présentons la circulation de l'eau circumpolaire profonde modifiée (MCDW) sur le plateau, en Antarctique de l'est, au large de la Terre Adélie. Le plateau Adélie est actuellement présenté comme la seconde source majeure d'eau antarctique de fond (AABW). La MCDW est une source de chaleur, de sel et de nutriments pour le plateau Antarctique. Améliorer la connaissance de la circulation de la MCDW et le transport de chaleur associé sur le plateau Antarctique est primordial pour mieux comprendre la formation d'AABW, la fonte des glaciers et des plateformes glaciaires ; et l'activité biologique du plateau. Grâce à la mise en ¿uvre d'un modèle inverse sur le plateau Adélie, nous avons proposé un schéma de la circulation moyenne pendant l'été et nous avons estimé les flux de chaleur et d'eau douce associés depuis l'entrée du plateau jusqu'aux région côtière proche du glacier du Mertz. Nous avons pu mettre en évidence des interactions potentielles entre les masses d'eau intermédiaires et profondes, d'une part, et le glacier, d'autre part, mettant en jeu des taux de fonte compatibles avec des estimations antérieures. Une seconde partie de ce travail s'est concentrée sur la variabilité du courant de la fréquence inertielle à l'échelle de temps saisonnière. Nous avons montré avec des observations in situ un fort cycle saisonnier de l'intensité et de la structure du courant sur le plateau Adélie, déjà suggéré dans des études antérieures basées sur des simulations numériques. Le cycle saisonnier doit donc être appréhendé pour bien comprendre les processus sur le plateau. / In this thesis, we study the Antarctic shelf ocean dynamics using in situ observation. We study the circulation of the Modified Circumpolar Deep Water (MCDW) on the East Antarctic shelf off Adélie Land presently recognized as the second major source of AntArctic Bottom Water (AABW). The MCDW is a source of heat, salt and nutrients for the Antarctic shelf. Improved knowledge of the circulation of the MCDW and the associated heat transport on the Antarctic shelf is very important to better understand the AABW formation, the role of the oceanic ice shelf, glacier melting and the biological activity. Thanks to the inverse model implemented on the Adélie Land shelf, we propose a comprehensive scheme of the mean circulation in summer 2008 and we estimate the associated heat and freshwater transports through the shelf break and farther on the shelf toward the Mertz Glacier. We present evidences of ocean induced glacial melt involving interaction of the dense shelf water and the MCDW with the glacier. A second part of this work focuses on the variability of the current from the inertial to the seasonal time scale using mooring observations collected in the AD, we show that a strong seasonal cycle exists in the current heading and vertical structure, in agreement with earlier model results, which implies that the seasonal cycle should be properly taken into account to correctly understand shelf-ocean processes in this region.

This thesis, structured in two parts, addresses a series of problems of relevance in the field of Spatial Geodesy. The first part delves into the application of satellite gravity data to enhance our understanding of water transport dynamics. Here, we present two significant contributions. Both are based on satellite gravity data but stem from different mission concepts with distinct objectives: time-variable gravity monitoring and high-resolution, accurate static geoid modelling. First, the fundamental notions about gravity are introduced and a brief summary is made of the different gravity satellite missions throughout history, with emphasis on the GRACE/GRACE-FO and GOCE missions, whose data are the basis of this work. The first application focuses on estimating water transport and geostrophic circulation in the Southern Ocean by leveraging a GOCE geoid and altimetry data. The Volume Transport across the Antartic Circumpolar Current is analyzed and the resulsts are validated validated using the in-situ data collected during the multiple campaigns in the DP. The second application uses time-variable gravity data from the GRACE and GRACE-FO missions to estimate the water cycle in the Mediterranean and Black Sea system, a critical region for regional climate and global ocean circulation. The analysis delves into the analysis of the different components of the hydrological cycle within this region, including the water flow across the Gibraltar Strait, examining their seasonal variations, climatic patterns, and their connection with the North Atlantic Oscillation Index. The second part of the thesis is more focused on data analysis, with the objective of developing mathematical methods to estimate the cross correlation function between two time series that are both unevenly spaced spaced (the sampling is not uniform over time) and observed at unequal time scales (the set of time points for the first series is not identical to the set of time points of the second series). Such time series are frequently encountered in geodetic surveys, especially when combining data from different sources. The estimation of the the cross correlation function for these time series presents unique challenges and requires the adaptation of traditional analysis methods designed for evenly spaced and synchronized time series. The two main contributions in this context are: (i) the study of the asymptotic properties of the Guassian Kernel estimator, that is the recommended estimator for the cross correlation function when the two time series are observed at unequal time scales; (ii) an extension of the stationary bootstrap that allows to construct bootstrap-based confidence intervals for the cross correlation function for unevenly spaced time series not sampled on identical time points.