La connaissance du microclimat et de l’évapotranspiration ou flux de chaleur latente qui représente la consommation réelle en eau de la culture à l’échelle des parcelles agricoles est une donnée importante pour comprendre le développement des cultures. La plupart des modèles permettant d’estimer l’évapotranspiration sont utilisés sur des surfaces homogènes sans tenir compte des interactions surface - atmosphère et de la variabilité spatiale du domaine agricole. Nous avons utilisé un modèle de couche limite atmosphérique afin de prendre en compte ces interactions. Une approche dite « patchée » permet d’introduire la variabilité spatiale des surfaces dans le modèle à partir des diverses proportions et des caractéristiques des principaux couverts végétaux qui composent le paysage. Une méthode d’assimilation variationnelle a été implémentée afin d’estimer certains paramètres du modèle difficile à connaître précisément. La méthode est basée sur le calcul de l’adjoint du modèle et utilise une température de surface observée par télédétection. L’approche développée est comparée à des approches plus simples considérant chaque type de surface indépendamment, mettant en évidence le rôle de la prise en compte de la variabilité spatiale de la surface sur la simulation du microclimat et des flux de surface / Knowledge of climate at regional scale and evapotranspiration (or latent heat flux which represents the actual water consumption of culture) is a key to understand the development of crops. Most of the methods aiming at estimating evapotranspiration assume homogeneous or decoupled atmospheric variables over the modelling domain without accounting for the feedback between surface and atmosphere. In order to analyse such dependencies and to predict microclimate and land surface fluxes we have developed a coupled atmospheric boundary layer - land surface model which accounts for the landscape heterogeneity using a tiled approach. We have implemented appropriate procedures (variational data assimilation) for assimilating remote sensing data into the model allowing to retrieve some input parameters difficult to estimate spatially (soil moisture and aerodynamic roughness). The developed method is compared to classical approaches considering each type of surface independently. Results are discussed in this paper

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-09-11T18:18:13Z No. of bitstreams: 1 diss-Raphael-Logato-de-Oliveira-PPGA.pdf: 25249109 bytes, checksum: bebdeef5c344d7c319f3fd7481af2cce (MD5) / Made available in DSpace on 2017-09-11T18:18:13Z (GMT). No. of bitstreams: 1 diss-Raphael-Logato-de-Oliveira-PPGA.pdf: 25249109 bytes, checksum: bebdeef5c344d7c319f3fd7481af2cce (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / A taxa de crescimento de uma colônia do coral endêmico brasileiro Siderastrea stellata, proveniente da Reserva Biológica do Atol das Rocas (3° 45’ S / 33° 40’ O – 3° 55’ S / 33° 50’ O), baseada em conta gem de bandas de crescimento e datação absoluta pelo método U-Th, seguidas de analises geoquímicas e isotópicas, revelaram uma variablidade das Temperaturas de Superfície do Mar (TSM) durante os últimos 39 anos. Os resultados demonstram uma forte correlação entre o crescimento do coral e a razão Sr/Ca, como também entre o Sr/Ca e U/Ca. O crescimento, Sr/Ca e U/Ca indicaram um forte sinal com frequência decadal, que é correspondente a um dos principais regimes de variabilidade do Atlântico Tropical Sul. Além disto, pode ser dito que o sinal do δ18O apresentou uma boa coerência com a ZCIT, indicando um potencial para futuros estudos sobre flutuações de salinidade. Porém, a falta de correlação entre os parametros geoquimicos com a TSM pode ser atribuída à limitação dos registros instrumentais de TSM disponíveis para a área de estudo (PIRATA), que são provenientes de bóias oceanográficas espaçadamente distribuídas. Assim, este estudo destaca alguns importantes fatores: a necessidade de se obter os registros de TSM in situ, para que seja possível estabelecer boas correlações entre esta e os traçadores; a clara relação entre o crescimento e Sr/Ca, sugerindo que este traçador pode não ser regulado somente pela TSM no caso de S. stellata; e a predominância de influências de variabilidades decadais e semi-decadais para esta região / One colony growth rate of an endemic Brazilian coral Sideratrea stellata from Atol das Rocas Biological reserve (3° 45’ S / 33° 4 0’ O – 3° 55’ S / 33° 50’ O), based on growth band counting and U-Th dating method, followed by geochemical analysis, revealed Sea Surface Temperature (SST) variability for the last 39 years. Results show a strong correlation between coral growth and Sr/Ca ratio, and also strong correlation between Sr/Ca and U/Ca. Growth, Sr/Ca and U/Ca indicate strong signal at decadal frequencies, corresponding to one of major South Tropical Atlantic variability. Moreover, it can be said that δ18O signal has showed good coherence with respect to ITCZ, pointing out to potential future studies about salinity fluctuations. However, the lack of correlation between SST and geochemical tracers can be attributed to instrumental SST data restriction for the study site, which comes from sparsely distributed oceanographic buyos (PIRATA). Insofar, this study highlights some important factors: the need for in situ SST registry in order to establish good correlations for SST and geochemical data; the clear relationship between coral growth and Sr/Ca, suggesting that this ratio may not be regulated by SST only for S. stellata; and the predominance decadal and semi-decadal variabilities at this region.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-09-27T14:22:18Z No. of bitstreams: 1 Dissertac...pdf: 4004750 bytes, checksum: c28f16763d698bcdf286109327f4a3a0 (MD5) / Made available in DSpace on 2017-09-27T14:22:18Z (GMT). No. of bitstreams: 1 Dissertac...pdf: 4004750 bytes, checksum: c28f16763d698bcdf286109327f4a3a0 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / A porção equatorial Oeste do Atlântico Sul é uma região-chave para o estudo das variabilidades climáticas, já que esta área é a principal saída de calor e sal para as altas latitudes do hemisfério norte através da Corrente Norte do Brasil. Esta transferência inter-hemisférica é um dos fatores cruciais para o funcionamento da circulação termohalina no oceano Atlântico, conhecida como Atlantic Meridional Overturning Circulation (AMOC). Baseado nisto, o objetivo deste trabalho é apresentar uma reconstrução da temperatura da superfície do mar (TSM) ao longo dos últimos 40.000 anos, em um intervalo que engloba o Ultimo Máximo Glacial (UMG) e o Holoceno. Para isto, foram empregados três testemunho sedimentares recuperados na margem Nordeste do Brasil. Dois destes testemunhos (MC 17/2 e MC 11/1) tiveram sua cronologia combinada, para juntos formarem um registro único do Holoceno. O terceiro testemunho (MC 10/3) enfoca o UMG e a fase de degelo até o início do Holoceno. Como proxies para a reconstrução paleoceanográfica da TSM foram empregados o isótopo estável de oxigênio (δ18Oc) do foraminífero planctônico Globigerinoides ruber (branco 250 – 300 μm), a Técnica do Análogo Moderno (TAM) e a análise faunística da assembleia de foraminíferos planctônicos na fração 150 μm. Os resultados para o UMG mostram a existência de dois cenários distintos que se separam em 21 k anos AP. Antes desta data condições mais frias na ordem de 2 ºC existiram na região, como ficou evidenciado pelos valores mais positivos do δ18Oc, pelas menores TSM reconstruídas pela TAM e pela maior abundância de foraminíferos planctônicos relacionados a produtividade e profundidade, como Globigerina glutinata, Neogloboquadrina dutertrei, Globorotalia truncatulinoides (dextral e sinistral) e Globorotalia inflata. Após 21 k anos AP uma forte transição ocorre no δ18Oc e na abundância absoluta de foraminíferos planctônicos, indicando a entrada de condições mais quentes na região, principalmente durante o evento Heinrich 1 (H1) e o Younger Dryas (YD). Este intervalo, que inclui a fase de degelo e parte do Holoceno é marcado pela redução das espécies relacionada a produtividade e profundidade e pelo aumento das espécies de águas quentes e superficiais. O retorno da espécie Globorotalia menardii em 21 k anos AP pode indicar a reativação do transporte de águas quentes do Oceano Índico para o Atlântico Sul realizado pela Corrente das Agulhas durante a fase de degelo. Os dados apresentados aqui demonstram que o Atlântico equatorial Oeste responde a entrada de água doce no Atlântico Norte e ao transporte de águas quentes via Corrente das Agulhas, e que o balanço destes dois fatores foi crucial para o retorno da AMOC no fim do UMG. Os resultados para o Holoceno mostraram que a região vem sofrendo um aumento progressivo da TSM da ordem de 1 ºC principalmente após o Holoceno médio, onde alterações nos padrões orbitais podem ter modificado a distribuição da energia solar no planeta. Análises espectrais sobre os dados mostram uma série de periodicidade quase cíclicas centradas em 4.1 – 3.8 kyr, 1.5 – 1.0 kyr, ~ 700 yr, 570 – 560 yr, ~ 390 yr, ~350 yr e ~ 330 yr e podem refletir a ação de forçantes climáticas externa (variabilidade solar) e internas (sistema oceano-atmosfera) transmitidas pela circulação termohalina globalmente. / The western equatorial Atlantic is a key region for the study of climate variability, as this area is the main source of heat and salt toward high latitudes of northern Atlantic through the North Brazil Current. This interhemispheric transfer is one of the crucial factors for the thermohaline circulation in the Atlantic Ocean, known as Atlantic Meridional Overturning Circulation (AMOC). Based on this, the aim of this work is to show a reconstruction of sea surface temperature (SST) over the last 40,000 years, into a range that comprises the Last Glacial Maximum (LGM) and Holocene. For this, we used three sedimentary records recovered in Northeast Brazilian margin. Two of these records (MC 17/2 e MC 11/1) were combined to generate a single record of Holocene. The last record comprises the LGM until the early Holocene. As proxies for the reconstruction of SST were employed the oxygen stable isotope (δ18Oc) of planktonic foraminifera Globigerinoides ruber (white 250 – 300 μm), the Modern Analogue Technique (MAT) and the assemblage of planktonic foraminifera in the size-fraction of 150 μm. The results for the LGM showed the existence of two different scenarios that were separated at 21 kyr BP. The heavier oxygen values recorded prior to 21 kyr BP demonstrated that the Last Glacial Maximum was up to 2ºC colder than Holocene. After 21 kyr BP, a strong shift to lighter values indicated the onset of warmer conditions during deglacial, especially during Heinrich event 1 and the Younger Dryas. The planktonic foraminifera assemblage as species related to productive or deep waters confirmed the conditions indicated by the oxygen composition; i.e., Globigerinita glutinata, Neogloboquadrina dutertrei, Globorotalia truncatulinoides (left and right coiling) and Globorotalia inflata were more abundant prior to 21 kyr BP. With the increase in the sea surface temperature after 21 kyr BP, the abundance of these species was reduced, particularly for G. glutinata and G. inflata, and the abundance of species found in warmer waters increased, especially for Globigerinella siphonifera. The species Globorotalia menardii, which was absent in the Last Glacial Maximum, reappeared after 21 kyr BP, which may have been a response to the Agulhas Leakage that released warmer waters into the South Atlantic at the beginning of deglacial. The data presented here indicate that the western equatorial Atlantic responded to the meltwater pulse at high latitudes of the northern Atlantic and to warm waters from the Indian Ocean. The balance between these two factors was crucial to the development of the Atlantic Meridional Overturning Circulation at the end of the LGM. The results of Holocene showed that the region has suffered a gradual increase in SST of around 1 ºC, mainly after the mid-Holocene, where changes orbital patterns may have changed the distribution of solar energy on the planet. Spectral analyzes on the data demonstrated a series of periodicities centered at 4.1 – 3.8 kyr, 1.5 – 1.0 kyr, ~ 700 yr, 570 – 560 yr, ~ 390 yr, ~350 yr e ~ 330 yr and can be related of climate forcing transmitted globally by the thermohaline circulation.

Le géothermomètre Δ47 est basé sur la relation entre l’abondance des liaisons 13C–18O des carbonates et la température de calcification. Ce proxy contourne potentiellement les limites des autres thermomètres (δ18O, Mg/Ca) pour reconstruire les paléo-températures des océans, expliquant son développement exponentiel depuis dix ans. Cette thèse teste pour la première fois le potentiel et les limites de la thermométrie Δ47 sur les coccolithes, des nannofossiles calcaires produits par des organismes calcifiants dans la zone photique. Ces biominéraux calcitiques et ubiquistes constituent une part importante de l’archive sédimentaire. Des cultures in vitro nous ont permis d’établir que trois espèces de coccolithes actuelles enregistrent la même relation Δ47 – T que la calcite inorganique, alors qu'elles présentent de très larges effets vitaux en δ18O (±5‰). Nous concluons que ces espèces de coccolithes d'importance géologique ne présentent pas d’effets vitaux en Δ47. Nous avons ensuite appliqué le Δ47 à l’étude des sédiments enregistrant l’événement d’anoxie océanique du Toarcien (–183 Ma) au cours duquel les reconstructions de températures restent encore ambigües, notamment du fait de la méconnaissance de la composition isotopique en oxygène de l’eau de mer. Sur la base des données Δ47 acquises, nous proposons des températures élevées (de l’ordre de 36°C), mais restant relativement stables sur l'intervalle d'étude. En couplant ces températures aux données de δ18O des carbonates, nous suggérons une variation importante du δ18O de l'eau de mer dans le Bassin de Paris lors de la mise en place des faciès black shales. Enfin, sur des sédiments pélagiques subactuels, l’une des espèces étudiées présente des déséquilibres isotopiques en Δ47 non observés en culture et explicables par d’autres paramètres environnementaux comme l’intensité lumineuse. Cette thèse illustre le potentiel du thermomètre Δ47 des coccolithes en différents contextes, ouvrant un vaste champ d’application de reconstruction des paléo-environnements sur le Méso-Cénozoïque / The Δ47 geothermometer relies on the relationship between the 13C–18O abundance in carbonateand temperature of calcification. This proxy has the potential to overcome limitations of other thermometers(δ18O, Mg/Ca) to reconstruct oceanic paleotemperatures. This thesis evaluates for the first time the potentialand the limitations of the Δ47 thermometry of the coccoliths, the calcareous nannofossils produced byorganisms calcifying in the photic zone. These calcitic and ubiquitous biominerals represent an importantpart of the sedimentary archive. In vitro cultures allow us to establish that three modern coccoliths speciesrecord the same Δ47–T relation than inorganic calcite, although exhibiting substantial δ18O vital effects(±5‰). We conclude that these coccoliths species do not present any Δ47 vital effect. We subsequentlyapplied the Δ47 proxy to sediments from the Toarcian oceanic anoxic events (–183 Ma) during which thetemperatures reconstructions are still elusive, mainly due to the unknown oxygen isotopic composition ofseawater. On the basis of our Δ47 data, we infer relatively high, yet steady temperatures (around 36°C) duringthe examined interval. By combining these Δ47-derived temperatures to carbonate δ18O data, we can suggestdrastic change in the seawater δ18O composition in the Paris Basin at the onset of black shale deposition. Acore top calibration of Δ47 of coccoliths revealed that one of the studied cultured species exhibits Δ47disequilibrium that is accountable by other environmental parameters, such as light irradiance in the naturalenvironment. Thus, this thesis illustrates the potential of the coccolith Δ47 thermometer in different settings,opening a wide range of application to reconstruct the palaeoenvironments over the Meso-Cenozoic Eras

In first part of the study we discuss impact of dynamical core in simulation of tropical rainfall. Over years many new dynamical cores have been developed for atmospheric models to increase efficiency and reduce numerical errors. CAM3.1 gives an opportunity to study the impact of the dynamical core on simulations with its three dynamical cores namely Eulerian spectral(EUL) , Semilagrangian dynamics(SLD) and Finite volume(FV) coupled to a single parametrization package. A past study has compared dynamical cores of CAM3 in terms on tracer transport and has showed advantages using FV in terms of tracer transport. In this study we compare the dynamical cores in climate simulations and at their optimal configuration, which is the intended use of the model. The model is forced with AMIP type SST and rainfall over seasonal, interannual scales is compared. The significant differences in simulation of seasonal mean exist over tropics and over monsoon regions with observations and among dynamical cores. The differences among EUL and SLD, which use spectral transform methods are lesser compared that of with FV clearly indicating role of numerics in differences. There exist major errors in simulation of seasonal cycle in all dynamical cores and errors in simulation of seasonal means over many regions are associated with errors in simulation of seasonal cycle such as over south china sea. Seasonal cycle in FV is weaker compared to SLD and EUL. The dynamical cores exhibit different interannual variability of rainfall over Indian monsoon region, the period of maximum power corresponding to a dynamical core differs substantially with another. From this study there seems no superiority associated with FV dynamical core over all climate scales as seen in tracer transport. The next part of the study deals with impact of diurnal ocean atmosphere coupling in an AGCM,CAM3.1. Due to relatively low magnitude of diurnal cycle of SST and lack of SST observations over diurnal scales current atmospheric models are forced with SSTs of periods grater than a day. CAM 3.1 standalone model is forced with monthly SSTs but the interpolation is linear to every time step between any two months and this linear interpolation implies a linear diurnal and intraseasonal variation of SST which is not true in nature. To test the sensitivity of CAM3.1 to coupling of SST on diurnal scales, we prescribed over tropics(20S20N) a diurnal cycle of SST over daily mean interpolated SST of different magnitudes and phase comparable to observations. This idea of using a diurnal cycle of SST retaining seasonal mean SST in an atmospheric model is novel and provides an interesting frame work to test sensitivity of model to interpolations used in coupling of boundary conditions. Our analysis shows a high impact of using diurnal cycle of SST on simulation of mean rainfall over tropics. The impact in a case where diurnal cycle of SST is fixed and retained to daily mean SST implies that changes associated with a coupled model are to some extent due to change in representation of diurnal cycle of SST. A decrease of excess rainfall over western coast of Bay of Bengal and an increase of rainfall over northern bay of Bengal in such case is similar to the improvement due to coupling atmospheric model to a slab ocean model. This also implies that problems with current AMIP models in simulation of seasonal mean Indian monsoon rainfall could be due to erroneous representation of diurnal cycle of SST in models over this region where the diurnal cycle of SST is high in observations. The high spatial variability of the impact in various cases over tropics implies that a similar spatial variation of diurnal cycle could be important for accurate simulation of rainfall over tropics. Preliminary analysis shows that impact on rainfall was due to changes in moisture convergence. We also hypothesized that diurnal cycle of SST could trigger convection over regions such as northern Bay of Bengal and rainfall convergence feedback sustains it. The impact was also found on simulation of internal interannual variability of rainfall

Community Climate Model 3 (CCM3) is run on an idealized all land zonally symmetric planet (Terra Blanda) with no seasonality, no snow and fixed soil moisture to obtain a stationary time series effectively much longer than conventional runs with geography and seasons. The surface temperature field generated is studied to analyze the spatial and temporal spectra, estimate the length scale and time scale of the model, and test the linearity of response to periodic and steady heat source forcings. The length scale of the model is found to be in the range of 1000-2000 km and the time scale is estimated to be 24 days for the global average surface temperature field. The response of the global average temperature is found to be fairly linear to periodic and the steady heat source forcings. The results obtained are compared with the results of a similar study that used CCM0. Fluctuation Dissipation theorem is also tested for applicability on CCM3. The response of the surface temperature field to a step function forcing is demonstrated to be very similar to the decay of naturally occurring anomalies, and the auto-correlation function. Return period of surface temperature anomalies is also studied. It is observed that the length of the data obtained from CCM3, though sufficient for analysis of first and second moments, is significantly deficient for return period analysis. An AR1 process is simulated to model the global averaged surface temperature of Terra Blanda 3 to assess the sampling error associated with short runs.

In many micrometeorological studies, building resolving models usually assumea neutral atmosphere. Nevertheless, urban radiative transfers play an important role because of their influence on the energy budget. In order to take into account atmospheric radiation and the thermal effects of the buildings in simulations of atmospheric flow and pollutant dispersion in urban areas, we have developed a three-dimensional (3D) atmospheric radiative scheme, in the atmospheric module of the Computational Fluid Dynamics model Code_Saturne. The radiative scheme was previously validated with idealized cases, using as a first step, a constant 3D wind field. In this work, the full coupling of the radiative and thermal schemes with the dynamical model is evaluated. The aim of the first part is to validate the full coupling with the measurements of the simple geometry from the 'Mock Urban Setting Test' (MUST) experiment. The second part discusses two different approaches to model the radiative exchanges in urban area with a comparison between Code_Saturne and SOLENE. The third part applies the full coupling scheme to show the contribution of the radiative transfer model on the airflow pattern in low wind speed conditions in a 3D urban canopy. In the last part we use the radiative-dynamics coupling to simulate a real urban environment and validate the modeling approach with field measurements from the 'Canopy and Aerosol Particle Interactions in Toulouse Urban Layer' (CAPITOUL)

Les méthodes optiques passives de mesures de température comme la thermographie ou la pyrométrie optique sont intéressantes car elles permettent une mesure non intrusive de l’objet cible à condition de connaître le facteur d’émission. La connaissance de ce facteur est critique pour déterminer la température de surface par le rayonnement thermique émis dans un domaine spectral. Le pyromètre bichromatique impulsionnel permet de surmonter la connaissance de ce paramètre à condition que le choix des valeurs de longueurs d’onde soit fait avec précautions. Lorsque l’objet à mesurer est situé dans un environnement industriel, de telles méthodes optiques sont fortement perturbées par la présence d’un milieu optiquement absorbant. C’est également le cas pour des objets situés dans des environnements très chauds qui émettent d’intenses radiations interférentes. Dans cette thèse, nous présentons une méthode radiométrique active bichromatique pour mesurer la température d’une surface en milieu industriel. Cette méthode est basée sur une excitation locale par une source laser modulée dans l’infrarouge. La détection de la température qui est corrélé avec l’excitation permet d’extraire par détection synchrone le signal modulé noyé dans un bruit jusqu’à un million de fois supérieur. Travailler à courtes longueurs d’onde (domaine visible et proche infrarouge) offre une grande dynamique et minimise l’erreur induite par les variations d’émissivité avec la longueur d’onde. Ce système collecte le rayonnement émis par l’objet à distance, de quelques mètres à plusieurs dizaines de mètres selon la configuration du système optique. Le principe de la méthode de mesure, le système optique et l’appareillage sont présentés dans ce rapport ainsi que les études théoriques et expérimentales sur la sensibilité, sa calibration et les résultats obtenus sur différents sites industriels. / Optical passive methods of temperature measurements such as thermography or optical pyrometry are very interesting because they allow a non-intrusive measurement with the target object provided to know the emission factor. The knowledge of this factor is critical for determining the actual temperature of a surface from the thermal radiation emitted in a wavelength band. The bichromatic pulsed pyrometer allows to overcome the knowledge of this parameter provided that precautions are taken in the choice of the values of wavelengths. When the object to be measured is placed in industrial environments, such passive optical methods are greatly disturbed by the presence of an optically absorbing medium. It is also distorted for objects located in very hot environments emitting intense interfering radiation. In this thesis, we present an active bichromatic radiometric method for measuring the temperature of a surface in harsh environments. The method is based on a localized excitation by a modulated laser source in the infrared range. Detecting the temperature range which is correlated with the excitation allows a synchronous detection to extract the signal embedded in a noise up to 106 times superior. Working at short wavelengths (visible range and near infrared range) offers a large dynamic range and minimizes the error due to variations in emissivity with the wavelength. This system collects the radiation emitted by the object at a distance from a few meters up to dozens of meters depending on the configuration of the optical system. The principle of the measurement method, the optical wavelength separation system and the telemetry apparatus are presented in this report as well as the theoretical and experimental study of the sensitivity of the device, its calibration and the results obtained in different industrial sites.

A gestão de recursos hídricos tornou-se cada vez mais complexa devido ao rápido crescimento sócio-econômico e as mudanças ambientais nas bacias hidrográficas nas últimas décadas. Modelos computacionais são importantes ferramentas de suporte na gestão de recursos hídricos e tomada de decisões devido a sua funcionalidade, provendo informações importantes sobre os principais processos físicos, químicos e biológicos, e permitindo melhorar o entendimento desses processos, os quais ocorrem em diferentes escalas espaciais e temporais. Na presente tese, o objetivo foi compreender o funcionamento hidrológico do sistema integrado bacia hidrográfica - lagoa, e os efeitos na hidrodinâmica do lago, utilizando como suporte o acoplamento da modelagem hidrológica - hidrodinâmica, e o uso de técnicas de sensoriamento remoto para o monitoramento de parâmetros de qualidade da água (e.g., clorofilaa, temperatura da superfície d’água e níveis da água). A área de estudo é a bacia hidrográfica da Lagoa Mirim, localizada no sul do Brasil, possuindo uma área total de 58.000 km2 (56% no Uruguai e o restante no Brasil). Foram propostos e testados modelos empíricos para estimativa de clorofila-a emumlago raso subtropical, baseados em imagens do sensor MODIS e técnicas estatísticas. Além disso, foi desenvolvido e avaliado o acoplamento da modelagem hidrológica-hidrodinâmica de grande escala e o sensoriamento remoto. O modelo hidrológico distribuído de grande escala MGBIPH acoplado com o modelo hidrodinâmico IPH-ECO foi utilizado para simular a bacia hidrográfica e os principais componentes hidrodinâmicos da Lagoa Mirim. O modelo mostrou bom desempenho quando comparado com observações de vazões, além de dados provenientes de sensoriamento remoto, através de altimetria espacial. As simulações mostraram importantes aspectos sobre a estrutura de fluxo, campos de velocidade e níveis d’água na lagoa, assim como a influência de grandes rios, forçantes externas como o vento (intensidade e direção) e o impacto do estressor antrópico (retiradas para irrigação) no sistema. As simulações permitiram avaliar aspectos relacionados com as variações espaciais e temporais (diurna, mensal, sazonal e inter-anual) da temperatura da superfície da água, a dinâmica dos fluxos de calor (sensível e latente) e os efeitos de eventos meteorológicos de pequena escala como frentes frias, os quais têm um impacto significativo sobre a temperatura superficial da água e os fluxos de calor na lagoa. Quanto aos modelos empíricos para estimativa de clorofila-a a partir do MODIS, os resultados mostram que um simples e eficiente modelo desenvolvido a partir de análise de regressão múltipla, apresentou ligeiras vantagens sobre os modelos de redes neurais artificiais, modelos multiplicativos não paramétricos e modelos empíricos (e.g., Appel, Kahru, FAI e O14a) usualmente utilizados na estimativa de Chl-a em ambientes aquáticos. Resultados também indicam que é inapropriado generalizar um único modelo desenvolvido a partir do conjunto total de dados, para estimar concentrações de Chl-a na lagoa, o que corrobora a heterogeneidade espacial na distribuição de Chl-a e as diferenças entre regiões (litoral e pelágica). A modelagem hidrológica-hidrodinâmica de grande escala apoiada por informação de sensoriamento remoto, mostrou ser uma abordagem promissora para o entendimento da estrutura e funcionamento de lagoas rasas de grande porte e longo prazo, úteis para a gestão integrada dos recursos hídricos. / The last decade, the water resource management is being complex due to the rapid socioeconomic development and environmental changes in river basins. Computations models are important support tools in water resource management and make decision providing important information and allowing a better comprehension of the physical, chemical and biologic processes, which occur in di erent temporal/spatial scales. In this thesis, the objective was to understand the hydrological functioning of the integrated basin- lake system and its e ects on hydrodynamics, using hydrodynamic - hydrodynamic modeling and water quality monitoring (e.g., chlorophyll-a, water surface temperature and water levels) from remote sensing techniques. The study area is the Lake Mirim basin, located between Brazil and Uruguay (basin total area 58.000 km2). Empirical models were proposed and tested to chlorophyll-a estimation in a shallow subtropical lake, based on MODIS imagery and statistics techniques. In addition, we developed and assessed the coupling of large scale hydrological/hydrodynamic modeling and remote sensing techniques. The large-scale distributed hydrological model MGB-IPH coupled with the hydrodynamic model IPHECO were used to simulate the river basin and the hydrodynamic components of the Lake Mirim. The coupled model showed good performance when compared to in-situ measurements and satellite altimetry data. The simulations showed important aspects relate to flow structure, velocity fields and lake water levels, as well as the influence of large rivers, external forcing as such the wind (intensity and direction), and the impact of anthropogenic stressors (irrigation withdrawals) in the system. The simulations allowed assessing the spatial and temporal variations (diurnal, monthly, seasonal and inter-annual) in the water surface temperature, heat fluxes dynamics (sensible and latent) and the e ects of short time-scale events, as such cold fronts passages over the lake, which cause strong impacts on the water surface temperature and heat fluxes in the lake. Regarding the empirical models developed to chlorophyll-a estimation from MODIS imagery, the results showed that a simple and e cient model developed from multiple regression analysis, performed best in comparison with artificial neural network models, non-parametric multiplicative models, and empirical models (e.g., Appel, Kahru, FAI and O14a) common used in the Chl-a estimation in aquatics environments. Results also indicated that is inappropriate to generalize a single model developed from the total datasets to estimates Chl-a in the lake, which corroborates the spatial heterogeneity (Chl-a distribution) and the di erences among regions (littoral and pelagic). The synergy between large-scale hydrological-hydrodynamic modeling, in situ measurements and remote sensing techniques provided a promising approach to improve the comprehension of the structure and ecosystem functioning of large shallow lakes in long-term time scale, useful to water resources management.

The urban heat island (UHI) is a phenomenon of noticeably higher temperatures in the cities as compared to their respective surrounding areas. This thesis aims at characterizing the influence of city expansion to the urban heat island phenomenon. The study is carried out in a city of Caceres in the Spanish province of the same name. A model input data is obtained with Landsat multispectral images. The analysis of satellite images shows that functional vegetation cover and water surfaces help in mitigating urban heat island effect. However, the Caceres city expansion does not influence the urban heat island intensity. A possible explanation for it is as the city expanded the ratio of vegetation to dry land remains constant in time.