Sidney Sára Zanetti

Estimação da evapotranspiração de referência no estado do Rio de Janeiro usando redes neurais artificiais

This work was performed with the aim of proposing an artificial neural network (ANN) to estimate the reference evapotranspiration (ETo) as a function of geographic position coordinates and air temperature in the State of Rio de Janeiro. Data used for the network training were collected from 17 historical time series of climatic elements located in the State of Rio de Janeiro. The daily ETo calculated by Penman-Monteith (FAO-56) method was used as a reference for network training. ANNs of multilayer perceptron type were trained to estimate ETo as a function of latitude, longitude, altitude, mean air temperature, thermal daily amplitude and day of the year. After training with different network configurations, the one showing best performance was selected, and was composed by only one intermediary layer (with twenty neurons and sigmoid logistic activation function) and one output layer (with one neuron and linear activation function). According to the results obtained it can be concluded that, considering only geographical positioning coordinates and air temperature, it is possible to estimate daily ETo in 17 places of Rio de Janeiro State by using an ANN.

Validação do modelo ClimaBR em relação ao número de dias chuvosos e à precipitação total diária

This study was accomplished with the objective of validate the ClimaBR model in what refers to generate synthetic series of total daily rainfall in different Brazilian places. For that, synthetic series of rainfall were generated for 12 places, chosen in a distributed way, so that all the different homogeneous rainfall Brazilians regions were observed. Starting from the pluviometric series, available in the meteorological stations from selected places, the ClimaBR was used to generate the synthetic series of rainfall; it was generated 100-year-old series to each place. The results quality was analyzed comparing the adjustment among the observed values and the generated values by ClimaBR, through simple lineal regression and of other statistical indicators. The results obtained allow affirming that, in agreement with the conditions considered in the present study, the software ClimaBR presented good acting to generate of synthetic series of precipitation (number of wet days and daily total rainfall) for all of the tested places.

CLIMABR parte I: modelo para a geração de séries sintéticas de precipitação

In the agricultural area, many studies related to precipitation have tried to evaluate the effects resulting from its occurrence in surface runoff. In this case the knowledge of not only the information relative to precipitation, its duration and intensity of the rains, but, also the profile of the precipitation is of great importance. With this objective, the present work was carried out to develop a model called CLIMABR, for the generation of synthetic precipitation series and of the instantaneous profile associated to these for the climatic conditions of the State of Rio de Janeiro. Pluviometric and pluviographic data from eleven stations of the Fundacao Superintendencia Estadual de Rios e Lagoas - SERLA and of Companhia LIGHT - Servicos de Eletricidade S.A. were utilized. In the generated synthetic series, the number of rainy days were obtained, according to the probabilities associated to the Markov chain and the total daily precipitation. The comparison of the data generated by CLIMABR with the observed data showed a good performance of the model for the estimation of these variables.

Programa computacional para geração de séries sintéticas de precipitação

A computational model was developed to generate synthetic series of rainfall using the method developed by OLIVEIRA (2003). The software was developed in Borland Delphi 6.0 environment. The input data come from the daily precipitation data in the standardized format of the National Water Agency (ANA). The software is capable to generate synthetic series of daily rainfall containing the amount and the duration of the rainfall, and the standardized event time of the maximum instantaneous intensity. The generated synthetic series are stored in text-formatted files that may be accessed by others softwares and/or electronic datasheets. There were also presented graphs and tables format, to easily evaluate the performance of the method developed.

ANÁLISE DA DINÂMICA ESPAÇO-TEMPORAL DOS FRAGMENTOS FLORESTAIS DA SUB-BACIA HIDROGRÁFICA DO RIO ALEGRE, ES

Knowing the history of forest fragmentation in watersheds helps plan and implement practices based on restoration of degraded forest areas. Structural analysis of forest fragments in the Alegre River subwatershed, State of Espirito Santo, was based on landscape metrics using ArcGIS 10 software with Patch Analyst extension, regarding changes during 1975, 2002, and 2007. Analysis showed an increase of about 7% in the total area of forest cover and emergence of 645 new forest fragments. Numerous patches and a small drainage area resulted in a high perimeter-to-area ratio. Simple geometric shapes predominated in smaller patches ( 20 ha) were close to each other, with a tendency to decrease proximity metric values. The results show that despite increase in vegetated area, the environmental quality of forest remnants is highly jeopardized.

CLIMABR parte II: geração do perfil de precipitação

The research about precipitation in Brazil has been restricted, most of time, to predict the maximum - total - or probable maximum intensity, this being done on the basis of historical series. Only few projects consider the corresponding profiles to these precipitations. The lack of representative models has forced the use of models developed abroad, despite the fact that the obtained results demonstrate, many times, was in inadequability to represent the typical climatic conditions in Brazil. The aim of the present work to detail complementarily to the development of the CLIMABR model, described by Oliveira et al. (2003), and show its application for instantaneous profile generation associated to synthetic precipitation series, for the climatic conditions of the State of Rio de Janeiro. In the generated synthetic series were obtained for each simulated day, among other informations, the duration of the events, the standardized values of the instantaneous maximum precipitation and the time of its occurrence throughout the events. The last two values were utilized to get the precipitation profile represented by a double exponential function that was adjusted to each daily event.

Manning roughness coefficient for Paracatu river, Brazil

Pela teoria do escoamento em canais abertos, o coeficiente de rugosidade de Manning e um dos principais parâmetros para descricao da vazao sobre uma superficie. Uma das dificuldades da aplicacao da equacao de Manning e a definicao do seu coeficiente de rugosidade em rios e canais, razao pela qual o presente estudo tem como objetivo, estimar o coeficiente de rugosidade de Manning para os periodos de vazao minima e maxima media mensal, em alguns trechos do rio Paracatu, e propor um modelo baseado em redes neurais artificiais para estimar o coeficiente de rugosidade. O coeficiente foi determinado em funcao das caracteristicas geometricas do canal (area molhada, raio hidraulico e declividade do canal) e das series de vazao de seis postos fluviometricos do rio Paracatu. Utilizaram-se series de vazao de 21 anos (1976-1996). O coeficiente de rugosidade nao apresenta tendencia (maior ou menor) em funcao apenas do periodo seco ou de cheia. As caracteristicas da margem e do leito do rio influenciam diretamente nos valores de coeficiente de rugosidade. O modelo baseado em rede neural apresentou desempenho satisfatorio, o que possibilita estimar o coeficiente de rugosidade em funcao da cota, vazao, declividade e do raio hidraulico do rio.

Hydrologic modeling in a small watershed part I: improvement of the HidroBacia model

Testes preliminares realizados com o modelo hidrologico HidroBacia, indicaram desequilibrio no seu balanco de massa, despertando a necessidade de estudos visando ao seu aperfeicoamento; assim, o presente trabalho consistiu no aprimoramento do modelo HidroBacia a partir da localizacao e correcao de falhas no codigo-fonte do seu programa computacional, essas falhas foram identificadas atraves da depuracao do modelo durante simulacoes do hidrograma de escoamento superficial, utilizando-se dados de uma microbacia hidrografica experimental. A principal causa relacionada com o desequilibrio do balanco de massa do modelo, tinha referencia com a solucao das equacoes do modelo de ondas cinematicas usado na propagacao dos hidrogramas de escoamento superficial, cujo problema foi contornado pela substituicao do algoritmo linear utilizado, Bras (1990), pelo algoritmo nao-linear apresentado por Li et al. (1975). A partir desta modificacao, considerada principal, e outras modificacoes implementadas, o balanco de massa do modelo HidroBacia foi ajustado e suas simulacoes passaram a gerar estimativas coerentes. Em virtude das alteracoes efetuadas, o HidroBacia evoluiu da versao 1.0 para a versao 1.1.

Prognoses of diameter and height of trees of eucalyptus using artificial intelligence

Models of individual trees are composed of sub-models that generally estimate competition, mortality, and growth in height and diameter of each tree. They are usually adopted when we want more detailed information to estimate forest multiproduct. In these models, estimates of growth in diameter at 1.30m above the ground (DBH) and total height (H) are obtained by regression analysis. Recently, artificial intelligence techniques (AIT) have been used with satisfactory performance in forest measurement. Therefore, the objective of this study was to evaluate the performance of two AIT, artificial neural networks and adaptive neuro-fuzzy inference system, to estimate the growth in DBH and H of eucalyptus trees. We used data of continuous forest inventories of eucalyptus, with annual measurements of DBH, H, and the dominant height of trees of 398 plots, plus two qualitative variables: genetic material and site index. It was observed that the two AIT showed accuracy in growth estimation of DBH and H. Therefore, the two techniques discussed can be used for the prognosis of DBH and H in even-aged eucalyptus stands. The techniques used could also be adapted to other areas and forest species.

Water Quality in Micro-watersheds Under Different Land Uses in the Municipality of Alegre, Espírito Santo

The present study aimed to evaluate water quality attributes in micro-watersheds under different soil uses. Therefore, four micro-watersheds under the following vegetation cover were selected: pasture, primary forest reforestation, forest, and coffee plantation. Surface and underground water sampling was performed bimonthly between February and December 2014, where thermotolerant coliforms, dissolved oxygen, total nitrogen, phosphorus, turbidity, temperature, pH, biochemical demand for oxygen and total solids were analyzed. Descriptive analyses of each variable were performed during dry and rainy periods, and the values were compared with the normative standards established by Brazilian legislation. Water Quality Indices (WQIs) were also calculated for each collection site. All sites presented some type of nonconformity with human consumption standards. The highest WQI values were found in the forest area micro-basin, followed by the coffee plantation and pasture area micro-basins, highlighting the importance of forested areas for water quality.