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@PhDThesis{Rudorff:2013:OcCoVa,
               author = "Rudorff, Nat{\'a}lia de Moraes",
                title = "Ocean Colour Variability across the Southern Atlantic and 
                         Southeast Pacific",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2013",
              address = "S{\~a}o Jos{\'e} dos Campos",
                month = "2013-08-19",
             keywords = "bio-optical variability, uncertainties, ocean colour radiances, 
                         Southern Atlantic, Soueastern Pacific, variabilidade bio-optica, 
                         incertezas, radi{\^a}ncias da cor do oceano, Atl{\^a}ntico Sul 
                         Subtropical, Pac{\'{\i}}fico Sudeste.",
             abstract = "Ocean colour radiometry (OCR) provides essential information for 
                         studies of primary productivity, heat fluxes, and biogeochemical 
                         cycles in the upper ocean. Generalized OCR models relating 
                         satellite radiometric data to biogeochemical variables are 
                         developed using global in situ data sets. However, when applied to 
                         specific regions these models commonly give results with 
                         significant deviation from in situ measurements, mainly due to 
                         field and satellite measurement uncertainties and model 
                         underrepresentation of ocean colour variability. Hence to improve 
                         OCR products further understanding of the sources of measurement 
                         uncertainty and bio-optical variability across different oceanic 
                         regions is needed. This work was focused on the Southern Atlantic 
                         and Southeast Pacific Oceans encompassing important biogeochemical 
                         provinces with highly distinct optical waters. In situ data was 
                         collected during a summer campaign on board the research vessel 
                         Melville (MV1102 cruise). The first part of the investigation was 
                         an uncertainty analysis of the radiometric and bio-optical data 
                         with three main objectives: (i) test different radiometric 
                         techniques with above and in-water approaches (ii) apply closure 
                         analyses with forward modeling of remote sensing reflectance 
                         (Rrs); and (iii) analyze the impacts of the uncertainties on 
                         operational OCR models. The uncertainty analysis revealed moderate 
                         to high levels associated with the various techniques, with 12 to 
                         26\% relative differences (RD) for the ocean-colour bands (412- 
                         555 nm) and 3-12\% for the reflectance ratios (412-510/555). The 
                         use of a merged Rrs (Instruments, INS) reduced uncertainties since 
                         each individual technique was subject to different instrumental 
                         and environmental biases. Complete closure was not obtained, 
                         especially for the stations with more adverse environmental 
                         conditions (with winds, waves and clouds), with 18-34\% RD 
                         compared to modeled Rrs bands. Nonetheless, the impact of INS 
                         uncertainties on retrieved OCR products for empirical and 
                         semi-analytical (SA) models was still generally smaller than the 
                         intrinsic errors of the inversion schemes. Hence, the approaches 
                         applied to obtain more accurate measurements were effective in 
                         reducing the main sources of uncertainties. Significant sources of 
                         deviations of the OCR models were related to the optical 
                         variability of the study region and intrinsic model errors. The 
                         second part of the investigation analyzed the sources of 
                         bio-optical variability and their relations to biogeochemical 
                         variables across distinct provinces. The bulk inherent optical 
                         properties (IOPs) were in first order associated with the 
                         chlorophyll a concentration (Chla) gradient. Second order 
                         variations were explained by specific IOPs linked to the 
                         phytoplankton community structure, composition and size 
                         distribution of the particle assemblage and variability of the 
                         coloured dissolved and particulate organic matter (CDM). To 
                         synthetize the first and second order optical variations across 
                         the study region, a Regional Specific Optical Water Type (R-SOWT) 
                         classification was proposed by defining 5 classes that integrate 
                         the specific IOPs and bio-optical indices, i.e., a phytoplankton 
                         Size Index, CDM index, the specific backscattering coefficient 
                         (bbp/Chla) and spectral slope (\$\eta\$). The R-SOWT 
                         significantly improved the performance of SA models by using 
                         class-specific parameterizations, especially for the bbp retrieved 
                         by the GSM (Garver-Siegel-Maritorena) model, reducing from 35 to 
                         9\% RP, and the CDM absorption coefficient of the QAA 
                         (Quasi-Analytical Algorithm) model, reducing from 30 to 23\% RD. 
                         For more optically complex waters the improvements of the 
                         retrievals were much more significant. Further analysis of 
                         spatiotemporal variations of the optical relations and 
                         applicability of the R-SOWT for different seasons (and regions) 
                         are recommended for future studies. This approach has potential to 
                         improve OCR satellite products and be used as a new product that 
                         integrates relevant information for biogeochemical studies. 
                         RESUMO: A radiometria da cor do oceano oferece 
                         informa{\c{c}}{\~o}es essenciais para estudos de produtividade 
                         prim{\'a}ria, fluxos de calor e ciclos biogeoqu{\'{\i}}micos na 
                         superf{\'{\i}}cie dos oceanos. Modelos generalizados de cor do 
                         oceano que relacionam dados radiom{\'e}tricos de sat{\'e}lite 
                         com vari{\'a}veis biogeoqu{\'{\i}}micos s{\~a}o desenvolvidos 
                         com bases de dados globais in situ. No entanto, quando aplicados a 
                         regi{\~o}es espec{\'{\i}}ficas estes modelos apresentam desvios 
                         significativos que est{\~a}o relacionados a incertezas nas 
                         medidas in situ e satelitais, e sub-representa{\c{c}}{\~o}es da 
                         variabilidade da cor do oceano. Portanto, para a melhoria de 
                         produtos de cor do oceano {\'e} preciso conhecer melhor as fontes 
                         incertezas das medidas e a variabilidade bio-{\'o}ptica em 
                         diferentes regi{\~o}es oce{\^a}nicas. O presente trabalho teve 
                         como foco os Oceanos Atl{\^a}ntico Sul Sub-tropical e 
                         Pac{\'{\i}}fico Sudeste abrangendo importantes 
                         prov{\'{\i}}ncias biogeogr{\'a}ficas com {\'a}guas opticamente 
                         distintas. Dados in situ foram coletados durante uma campanha de 
                         ver{\~a}o a bordo do navio de pesquisa R/V Melville (MV1102). A 
                         primeira parte do trabalho compreendeu an{\'a}lises de incertezas 
                         dos dados radiom{\'e}tricos e bio-{\'o}pticos com tr{\^e}s 
                         objetivos principais: a) a compara{\c{c}}{\~a}o de diferentes 
                         t{\'e}cnicas de amostragem com instrumentos emersos e submersos; 
                         b) compara{\c{c}}{\~o}es com a reflect{\^a}ncia de 
                         sensoriamento remoto (Rsr) modelada; e c) an{\'a}lises dos 
                         impactos das incertezas em modelos operacionais de cor do oceano. 
                         As an{\'a}lises de incertezas revelaram n{\'{\i}}veis de altos 
                         a moderados associados {\`a}s diferentes t{\'e}cnicas, com 
                         diferen{\c{c}}as relativas (DR) de 12 a 26\% para as bandas de 
                         cor do oceano (412-555 nm) e 3 a 12% para as raz{\~o}es de bandas 
                         (412-510/555). O uso de uma medida de Rsr integrada (Instrumentos, 
                         INS) reduziu as incertezas j{\'a} que cada t{\'e}cnica 
                         individual estava sujeita a diferentes erros instrumentais e 
                         ambientais. O ajuste perfeito com a Rsr modelada n{\~a}o foi 
                         obtido, principalmente para as esta{\c{c}}{\~o}es com 
                         condi{\c{c}}{\~o}es ambientais mais adversidades (de vento, 
                         ondas e nuvens), com 18-34\% DR para as bandas espectrais. Ainda 
                         assim, o impacto das incertezas do INS foi de modo geral, menor 
                         que os erros intr{\'{\i}}nsecos aos modelos emp{\'{\i}}ricos e 
                         semi-anal{\'{\i}}ticos (SA) de cor do oceano. Dessa forma, os 
                         m{\'e}todos empregados para obter medidas mais acuradas foram 
                         razoavelmente eficazes em reduzir as incertezas. Desvios 
                         significativos dos modelos de cor do oceano foram relacionados 
                         {\`a} variabilidade {\'o}ptica da regi{\~a}o de estudo e erros 
                         intr{\'{\i}}nsecos aos modelos. A segunda parte da 
                         investiga{\c{c}}{\~a}o compreendeu an{\'a}lises das fontes de 
                         variabilidade bio-{\'o}ptica e suas rela{\c{c}}{\~o}es com as 
                         vari{\'a}veis biogeoqu{\'{\i}}micas nas diferentes 
                         prov{\'{\i}}ncias. A distribui{\c{c}}{\~a}o dominante das 
                         propriedades {\'o}pticas inerentes (POIs) esteve associada ao 
                         gradiente de concentra{\c{c}}{\~a}o de clorofila a (Cla). 
                         Varia{\c{c}}{\~o}es de segunda ordem foram relacionadas a POIs 
                         espec{\'{\i}}ficas associadas {\`a} estrutura da comunidade 
                         fitoplanct{\^o}nica, a composi{\c{c}}{\~a}o e 
                         distribui{\c{c}}{\~a}o do tamanho das part{\'{\i}}culas e 
                         {\`a} variabilidade da mat{\'e}ria org{\^a}nica dissolvida e 
                         particulada (MODP). Para sintetizar as varia{\c{c}}{\~o}es de 
                         primeira e segunda ordem na regi{\~a}o de estudo, uma 
                         classifica{\c{c}}{\~a}o Regional de Tipos Espec{\'{\i}}ficas 
                         de {\'A}guas {\'O}pticas (R-TEAO) foi proposta para definir 5 
                         classes, integrando as POIs espec{\'{\i}}ficas e 
                         {\'{\i}}ndices bio-{\'o}pticos, i.e., o {\'{\I}}ndice de 
                         tamanho do fitopl{\^a}ncton, {\'{\i}}ndice de CDM, o 
                         coeficiente especifico de retroespalhamento das 
                         part{\'{\i}}culas (bbp/Cla) e o par{\^a}metro de 
                         varia{\c{c}}{\~a}o espectral (\$\eta\$). O R-TEAO melhorou 
                         significativamente o desempenho de modelos SA com 
                         parametriza{\c{c}}{\~o}es especificas para cada classe, 
                         reduzindo a DR do bbp do modelo GSM01 (Garver-Siegel-Maritorena) 
                         de 35 a 9\% e o coeficiente de absor{\c{c}}{\~a}o do MODP de 30 
                         a 23\% para o modelo QAAv5 (Quase Analytical Algorithm). Para 
                         {\'a}guas mais opticamente complexas a melhoria dos modelos foi 
                         ainda mais significativa. An{\'a}lises das varia{\c{c}}{\~o}es 
                         espa{\c{c}}o-temporais das rela{\c{c}}{\~o}es {\'o}pticas e a 
                         aplicabilidade do R-TEAO para esta{\c{c}}{\~o}es sazonais 
                         diferentes e outras regi{\~o}es oce{\^a}nicas, s{\~a}o 
                         recomendadas para pesquisas futuras. O m{\'e}todo tem potencial 
                         de ser aplicado para a melhoria de produtos de cor do oceano por 
                         sat{\'e}lite e ser usado como um novo produto integrando 
                         informa{\c{c}}{\~o}es importantes para estudos 
                         biogeoqu{\'{\i}}mica.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
            committee = "Lorenzzetti, Jo{\~a}o Antonio (Presidente) and Kampel, Milton 
                         (Orientador) and Frouin, Robert (Orientador) and Novo, Evlyn 
                         M{\'a}rcia Le{\~a}o de Moraes and Ciotti, Aurea Maria and Lutz, 
                         Vivian",
         englishtitle = "Variabilidade da cor do oceano no Alt{\^a}ntico Sul Subtropical e 
                         Pac{\'{\i}}fico Sudeste",
             language = "en",
                pages = "321",
                  ibi = "8JMKD3MGP7W/3ERLCSE",
                  url = "http://urlib.net/rep/8JMKD3MGP7W/3ERLCSE",
           targetfile = "publicacao.pdf",
        urlaccessdate = "18 jan. 2021"
}


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