Nos últimos anos, dados de precipitação provenientes de sensoriamento remoto têm se tornado potencialmente úteis para estudos hidrológicos e agronômicos, ganhando maior importância em regiões onde as variáveis climáticas obtidas por métodos convencionais são limitadas ou inexistentes. Séries de precipitação são variáveis de entrada em modelos agrohidrológicos que simulam diferentes cenários em áreas agrícolas. Nesse sentido, esse trabalho teve como objetivo comparar os resultados da aplicação do modelo agro-hidrológico SWAP durante os anos 2008 e 2009, utilizando dados de precipitação obtidos por sensoriamento remoto e de forma convencional. Foram realizadas simulações com e sem o cultivo de soja, sendo analisadas as variáveis evaporação, transpiração, interceptação, escoamento superficial e drenagem pela base do perfil do solo. Essas simulações ocorreram em cenários caracterizados pelo solo predominante na sub-bacia do arroio Taboão, inserida na bacia do rio Potiribu, município de Pejuçara, Rio Grande do Sul. As maiores diferenças ocorreram no escoamento superficial e na drenagem pela base do perfil do solo. As estimativas das demais variáveis, mesmo que com diferenças menores, também indicaram que o emprego de uma série de dados pontuais de precipitação obtidos de satélite, a partir de uma resolução de 8 km, transferiu erros significativos aos resultados do balanço hídrico. Palavras-chaves USE OF RAINFALL DATA OBTAINED BY REMOTE SENSING IN AN AGRO-HYDROLOGICAL MODEL ABSTRACTIn the last years, precipitation data obtained from remote sensing have become potentially useful in agricultural and hydrological studies, acquiring greater importance in regions where climatic variables obtained by conventional methods are limited or nonexistent. Precipitation data are input variables for agro-hydrological models that simulate different scenarios in agricultural areas. Thus, this study compares the application results of the agrohydrological model SWAP during 2 years, 2008 and 2009, using rainfall data obtained by remote sensing and conventional methods. Simulations were performed with and with no

In this work, the data assimilation method namely ensemble Kalman filter (EnKF) is applied to the Tocantins River basin. This method assimilates streamflow results by using a distributed hydrological model. The performance of the EnKF is also compared with an empirical assimilation method for hourly time intervals, in which two applications based on information transfer from gauged to ungauged sites and real time streamflow forecasting are assessed. In the first application, both assimilation methods are able to transfer streamflow to ungauged sites, obtaining better results when more than one station located upstream or downstream of the basin are gauged. In the second application, integration of a real time forecast model with EnKF is able to absorb errors at the beginning of the forecast. Therefore, a greater efficiency in the Nash-Sutcliffe index for the first 144 hours in advance in relation to its counterpart without assimilation is obtained. Finally, a comparison between both data assimilation methods shows a greater advantage for the EnKF in long lead times.

RESUMONo presente trabalho é proposto um método de interpolação denominado CHUVSAT para ser avaliado como dado de entrada a um modelo hidrológico. Esse método calcula campos de chuva em forma de grade regular combinando chuva obtida por pluviômetros com dados de chuva por satélite. O CHUVSAT está baseado em um cálculo de médias ponderadas que considera a distância e o tipo de dado (pluviômetro ou satélite) como fonte de informação. Os dados de chuva de pluviômetros e de satélite foram obtidos da Agência Nacional de Águas (ANA) e do produto Tropical Rainfall Measuring Mission (TRMM), respectivamente. Os resultados foram avaliados comparando os hidrogramas calculados a partir de um modelo hidrológico distribuído com os hidrogramas observados em diferentes postos fluviométricos da bacia do Rio Tocantins. O desempenho do método CHUVSAT foi comparado ao desempenho do modelo hidrológico usando os dados do TRMM, e os dados de pluviômetros da ANA. Os resultados mostraram que a qualidade da série de vazões calculadas usando CHUVSAT conseguiu melhores coeficientes de eficiência de Nash-Sutcliffe para as séries geradas pelas fontes da ANA e do TRMM em bacias com área de drenagem da ordem de 5.000 km 2 . Em bacias maiores os resultados de CHUVSAT foram semelhantes aos obtidos utilizando apenas os dados de chuva observados em pluviômetros, enquanto os resultados utilizando dados de satélite foram inferiores. Conclui-se que a combinação de dados de satélite e pluviômetros tem potencial para aplicações hidrológicas, com ênfase na previsão de vazões em rios de grande porte. ABSTRACTIn this work, an interpolation method called CHUVSAT was proposed as input data to a hydrological model. This method calculates fields of precipitation in the form of a regular grid obtained by combining raingauges with satellite rainfall data. CHUVSAT is based on a calculation of weighted average that considers the distance and the type of data (raingauge or satellite) as a source of information. The rainfall data from raingauges and satellite were obtained from the National Water Agency (ANA) of Brazil and the Tropical Rainfall Measuring Mission (TRMM), respectively. The results were evaluated by comparing the calculated hydrograph from a distributed hydrological model with observed hydrographs at different streamflow stations in the Tocantins River basin. The performance of the method using CHUVSAT was compared to the performance of the hydrological model using only the data from TRMM and ANA. The results showed that the quality of the series of streamflows calculated using CHUVSAT was generally better for series generated by the sources of ANA and TRMM in basins with a drainage area of around 5,000 km 2 . In larger basin results using the combined method CHUVSAT were similar to those obtained using only the data observed in rainfall gauges, while results using satellite data were less good. We conclude that the combination of satellite rainfall and raingauges has a potential for hydrological applications such as streamflow forecasting for large ri...

A numerical model for the load transfer mechanism in mooring anchor systems, commonly used in offshore petroleum industry, is presented in this work. Special attention is paid to the mechanical modelling of the contact interaction of the two medium components, namely the soil and the embedded mooring line. Resorting to the "embedded element concept" [1], a mixed 3D-1D finite element formulation is developed in the context of finite elastoplasticity. A Tresca-like model is used to describe the nonlinear material behaviour of the surrounding soil under undrained conditions, whereas the embedded mooring line regarded as curvilinear bar-like inclusion is assumed to behave elastically with account for geometric nonlinearities. The Mohr-Coulomb model is employed to define the bond-stress and bond-slip relationships at the interface. Nonlinear static and dynamic analyses are performed with a corotational kinematic description in order to include large deformation in the problem [2]. Preliminary results indicate that the main frequencies of the dynamic load applied to the mooring line-soil system are much lower than those of the system itself, thus the overall system may be evaluated disregarding inertial effects. Further simulations based on parametric studies by varying relevant problem parameters are needed to corroborate this result. Moreover, the average load attenuation induced by friction along the soil/mooring line interface for the studied cases is around 25%. Formulation of the interface constitutive behaviour in the context of large strain to address large relative movements between embedded inclusion and surrounding soil is an ongoing task [3]. Parallel implementation of