Enilson Palmeira Cavalcanti

Programa computacional para a estimativa da temperatura do ar para a região Nordeste do Brasil

The objective of this research was to establish a model to estimate air temperature (Estima_T) as a function of geographical coordinates and Sea Surface Temperature Anomalies (SSTA). The mean monthly time series of air temperatures (daily mean, minimum and maximum) of 69 weather stations and SSTA of the Tropical Atlantic were analyzed. The model Estima_T showed good agreement between real and estimated air temperature data of Northeast Brazil. The results showed statistically significant correlation at 1% level between observed air temperatures and those estimated by model in the whole area of study.

Análises da precipitação pluvial no Estado da Paraíba com base na teoria da entropia

The objective of this study was the evaluation of the rainfall variability in Paraiba state. Daily rainfall observed from a network of 58 rain gauges in Paraiba State and mean daily temperature observed at Campina Grande weather station were analyzed using entropy theory. The results showed that rainfall entropy is high in localities and periods with high rainfall values and is low in localities and periods with low rainfall values. Maximum values of rainfall entropy occurred in the rainy period and minimum values occurred in the dry period. However, the entropy of the temperature time serie was constant, with maximum value of 8.53 bits. This study shows that for any time series the entropy decreases exponentially with increase of standard deviation.

Fostering collaboration to better manage water resources

Good water management is literally vital for the arid and semi‐arid regions of the planet. Yet good water management requires multidisciplinary expertise, since one must consider climatic, hydrological, economical and social aspects to make balanced decisions on water usage. We here present SegHidro, a Grid portal designed to foster scientific, technical and operational collaboration to improve water resources management. The portal targets researchers and decision makers, enabling them to execute and couple their computational models in a workflow. The portal provides a framework which allows seamless integration of the models, meaning that each phase of the flow may be executed by a different expert and that the resulting data are shared among other portal users. Due to the nature of these applications and the need to execute many prospective scenarios, their execution requires high computing power. However, we go beyond providing high‐performance computational Grid capabilities. We also enable people to complement each others expertise in understanding the trade‐offs in the water allocation decisions. The SegHidro portal is about sharing: human expertise, data and computing power. Copyright

Wind energy potential for the prevailing direction in Northeast Brazil

Hourly mean data of wind speed and direction, measured with a Fuess anemograph at 10 m height, were used in this study. These data were collected from January 1977 to December 1981 at 77 weather stations located in the Northeast of Brazil. The main objective of the study was to determine the wind energy potential for the predominant wind direction of selected stations; therefore, the identification of the relative frequency related to the hourly mean wind speed of the predominant direction was carried out. Then, the parameters, of a Weibull distribution related to the hourly mean wind speed of the predominant direction at each station were estimated by Moments and Graphical methods. The results show that the predominant wind direction in Northeast as a whole is East Ward, with variation to Northeast and Southeast. The Weibull model fitted very well to the observed frequency distribution of the wind speed data used in this research. The lowest and the highest wind energy potential were observed in the States of Maranhao and Rio Grande do Norte, respectively. At Acarau (Ceara) the highest monthly wind energy potential, of 138.30 W m-2 was observed. On the other hand, the lowest monthly wind energy potential (0.022 W W m-2) was registered at Alto Parnaiba, MA.

Evaluation of the Wind Power in the State of Paraíba Using the Mesoscale Atmospheric Model Brazilian Developments on the Regional Atmospheric Modelling System

This work aims to describe the wind power density in five sites in the State of Paraiba, as well as to access the ability of the mesoscale atmospheric model Brazilian developments on the regional atmospheric modeling system (BRAMS) in describing the intensity of wind in Sao Goncalo Monteiro, Patos, Campina Grande, and Joao Pessoa. Observational data are wind speed and direction at 10 m high, provided by the National Institute of Meteorology (INMET). We used the numerical model BRAMS in simulations for two different months. We ran the model for rainy months: March and April. It was concluded that the BRAMS model is able to satisfactorily reproduce the monthly cycle of the wind regime considered, as well as the main direction. However the model tends to underestimate the wind speed.

Energia estática sobre o norte e nordeste do Brasil relacionada com a temperatura da superfície do mar

Some aspects of the large scale atmospheric general circulation, in the North and Northeast Brazil, which are related to the Sea Surface Temperature (TSM) of the Tropical Atlantic and Pacific oceans were investigated from the apparent heat source and the humidity sink. Were utilized the monthly data variables temperature, specific humidity, zonal and meridional wind components and geopotential height from National Centers for Environment Prediction/National Center for Atmospheric Research (NCEP/NCAR). The used data are spaced in a grating of 2.5°x 2.5° latitude and longitude, for the standard levels from 925 to 100 hPa. Besides, the used are TSM data from a 2° x 2° latitude and longitude grid. Four episodes of ENSO and four of dipole pattern were selected. The study refers to the rainy quarter period of February to April. During the warm (cold) episodes of El Nino and positive dipole (La Nina and negative dipole) the atmosphere over the areas 1 and 2 (1-Noth and 2- Northeast of Brazil) were less (more) humid. The observed above (below) mean variations in the dry static energy were more stronger during the El Nino (La Nina) years when compared to the years of positive dipole (negative dipole). Smaller (larger) areas of convergence of dry static energy in the lower levels and divergence in the upper levels during the years of El Nino (La Nina) were encountered. During the positive (negative) dipole phases the convergence band of static energy over the Atlantic Ocean was observed more towards north (south). The Amazon region behaved as an apparent water vapor sink during the episodes of El Nino, La Nina and dipoles positive and negative. The Northeast Brazil region behaved as an apparent water vapor source during the episodes of El Nino and positive dipole years and as a sink during the episodes of La Nina and negative dipole year.

Fluxo de vapor de água atmosférico na obtenção do resíduo ET-P em três macrorregiões brasileiras

This paper presents an analysis of precipitation, evapotranspiration and ET-P residuals for three 10o by 10o latitude/longitude control areas over the northeast, north and southeast of Brazil. The resulting water vapor flux is calculated and compared to the residual. The analysis is performed through the NCAR/NCEP reanalysis data for the period from 1958 to 1998. Some aspects of both seasonal and interannual variation of these variables are presented for each depicted area. The main result is the good correlation between the residuals and the resulting water vapor flux with determination coefficients of 0.86, 0.84 and 0.74 for these respective regions.

Análise Comparativa da Velocidade do Vento Simulado Pelo BRAMS com Dados Observados e de Reanálises

Abstract Modeling is used as a useful tool in the field of Meteorology. Therefore, the objective is to adjust the BRAMS (Braziliandevelopments on the Regional Atmospheric Modeling System) by observed data and reanalysis generated by ERA-Interim, in order to validate wind simulations resolved by the model. This information is extremely useful in previousstudies in wind farm projects. For verification were chosen three anemometric towers, located in the localities ofDamian, Juazeirinho and Teixeira in the state of Paraiba. The comparison is made during the month of October 2010.The results show that the BRAMS model simulated satisfactorily the actual data for the entire study period, obtainingsignificant correlations of 99% and minor errors in all cases presented. Keywords: BRAMS, reanalysis, atmospheric modeling, wind. 1. Introducao Os recursos energeticos e suas aplicacoes necessitamde pesquisas que produzam conhecimentos cada vez maisdetalhados. Esta pratica conduz a um melhor aproveita-mento e uso mais sustentavel dos recursos naturais. Odesenvolvimento sustentavel visa utilizar os meios neces-sarios para suprir as necessidades da humanidade, semprivar as geracoes que virao de beneficiar-se dos mesmosrecursos naturais (Lopez, 2012). Neste contexto, uma dasenergias renovaveis mais promissoras e que gera menorimpacto sobre o ambiente e a que usa os ventos para gerareletricidade, por meio de aerogeradores.No Brasil, uma das maiores dificuldades relacionadascom estudos da variabilidade espacial e temporal do vento,e a falta de dados observados. Sendo assim, o uso de dadosde reanalise pode ser justificado pela possibilidade de

Uso do Modelo Brams na Obtenção da Precipitação para Entrada em Modelo Hidrológico Concentrado (Use of Brams Model in Obtaining the Precipitation for Input in Concentrated Hydrological Model)

Foram feitas comparacoes entre a media da precipitacao observada na bacia hidrografica do Rio Pianco com a precipitacao media obtida de duas diferentes formas: 1) gerada pelo modelo atmosferico por intermedio de parametrizacao e 2) obtida pelo balanco hidrico da atmosfera a partir de dados do modelo. O objetivo principal e de avaliar a geracao de dados de precipitacao por modelo atmosferico para entrada em modelos hidrologicos concentrados, tipo chuva-vazao, possibilitando previsoes de vazoes. Foram estabelecidos quatro periodos de dez dias para os meses de fevereiro de 2006, 2004 e 2003 e marco de 2005. O modelo atmosferico de mesoescala utilizado foi o Brazilian developments on the Regional Atmospheric Modeling System (BRAMS). Foram utilizados dados de reanalises do National Centers for Environment Prediction / National Center for Atmospheric Research (NCEP/NCAR) para efetuar as simulacoes em menor escala. Os resultados revelam aspectos interessantes na distribuicao de precipitacao sobre a bacia. Os dados de precipitacao gerados atraves do BRAMS subestimaram os dados observados, entretanto, apresentam boa correlacao. Os resultados demonstram que o modelo BRAMS constitui-se em ferramenta importante para fornecer dados de entrada para modelos concentrados de chuva-vazao possibilitando a previsao de vazoes. Palavras chave: fluxo de vapor d’agua, modelo BRAMS, chuva-vazao Use of Brams Model in Obtaining the Precipitation for Input in Concentrated Hydrological Model ABSTRACT Comparisons were made between the mean observed areal rainfall in the Pianco River basin with the mean rainfall obtained through two different ways: 1) generated by the atmospheric model through parameterization and 2) obtained by atmospheric water balance from the model data. The main purpose is to evaluate the precipitation data generated by the atmospheric model to be used as input in concentrated hydrological models, rainfall-runoff models, allowing runoff predictions . Four periods of ten days each were selected in February, 2003, 2004, 2006, and March, 2005. The mesoscale atmospheric model used was the Brazilian developments on the Regional Atmospheric Modeling System (BRAMS). Data from National Centers for Environment Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis were used to make the simulations on finer scale. The results show interesting aspects in the distribution of rainfall over the basin. Rainfall data generated by BRAMS underestimated the observed data; however, it shows good correlation. The results also show that the BRAMS model is an important tool to provide input data to concentrated rainfall-runoff models. Keywords: water vapor flux, BRAMS model, rainfall-runoff