Francisco de Assis Salviano de Sousa

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.

Análise da pluviometria e dias chuvosos na região Nordeste do Brasil

Rainfall daily data of 600 meteorological stations were analyzed to assess the changes in precipitation in northeastern Brazil. Maps of rainy day numbers and the coefficient of variation (CV) for rainfall and rainy days are presented. Autocorrelation function was obtained for the annual rainfall in northeastern Brazil. Results showed that the semiarid regions have a high coefficient of variation for both rainfall and rainy days than those located in northeastern coast and ´agreste´ of Brazil. The highest values of coefficient of variation are associated to the lowest values of rainfall and rainy days. The rainfall change in northeastern Brazil is smaller in rainy regions than in dry regions. The high changes in rainfall and rainy days are limiting features to the rainfed agriculture in semiarid environments. The correlograms of rainfall indicated significant trend for the limits of 95% confidence levels on some stations.

Escalas temporais da variabilidade pluviométrica na bacia hidrográfica do Rio Mundaú

The Rain Anomaly Index (RAI) and the Wavelet Analysis (WA) were used to study the rainfall variability in different regions of the Mundau river basin. ANA (Water National Agency) monthly rainfall data over the basin (States of Alagoas and Pernambuco) for the period 1955 to 1991 were used. The analysis were performed for three regions of this basin: High Mundau (HM), Medium Mundau (MM) and Low Mundau (LM). Analyses of the RAI annual series show distinct temporal variations among these regions, except for the predominance of dry years during the beginning of the analysis period. Therefore, in some years the large scale phenomena might have the same effect on the three regions of the Mundau basin, and have not on another. For WA and for each region a precipitation index calculated as the average of the normalized anomaly series of the stations was used. The results showed that the rainfall variability is defined by temporal multi-scales localized in certain time intervals. However, the ENSO related interannual variability and the decadal variability influenced the local rainfall variability. From these results, it is aimed that the Mundau river basin would have more information for the management of its water resources and climate monitoring.

Análise estatística de chuvas intensas na bacia hidrográfica do Rio Paraíba

This research was accomplished in the Paraiba river basin for to identify the space and temporal variability of the rains intense of 1, 2, 3, 4 and 5 days. The obtained results showed concentration of maximum values of the space variation of the rains intense in the east of the subbasin of Low Paraiba, south of the subbasin of the river Taperoa and center-north of the subbasin of High Paraiba. The analysis of the temporal variation did reveal that the months of larger occurrences of rains intense in the basin in study are: January, February, March and April. Soon after, the rains intense they were adjusted to the probability distribution function of Gumbel. The test Kolmogorov-Smirnov was used to verify the quality of those fittings.This research was accomplished in the Paraiba river basin for to identify the space and temporal variability of the rains intense of 1, 2, 3, 4 and 5 days. The obtained results showed concentration of maximum values of the space variation of the rains intense in the east of the subbasin of Low Paraiba, south of the subbasin of the river Taperoa and center-north of the subbasin of High Paraiba. The analysis of the temporal variation did reveal that the months of larger occurrences of rains intense in the basin in study are: January, February, March and April. Soon after, the rains intense they were adjusted to the probability distribution function of Gumbel. The test Kolmogorov-Smirnov was used to verify the quality of those fittings.

Modelagem hidrológica determinística e estocástica aplicada à região hidrográfica do Xingu- Pará

Hydrologic modeling is an important tool for the planning and management of water resources use in river basins. In this work, a two-parameter monthly deterministic hydrologic model and the stochastic model, ARIMA, were applied to simulate the monthly runoff of the Xingu river basin in the State of Para. The main objective of this work is to simulate the monthly runoff using the two models and to compare their results. The applied hydrological deterministic model has a simple structure and presented good results, but seems to be very sensitive to extreme precipitation events. The stochastic model ARIMA was able to capture the dynamic of the temporal series, presenting very satisfactory results for the simulation of the monthly runoff at the basin stations. Both models should be applied with caution during the rainy season, when extreme precipitation events and consequently peaks of runoff occur.

Artificial neural network applied to the forecast of streamflow in the Piancó River Basin

Streamflow forecasting in a water system is one of the techniques used to reduce the impact of the uncertainties of the climate on administration of the water resources. That technique can be considered as one of the principal challenges related to the integrated knowledge of the climatology and of the hydrology of the river basin. The aim of this work was to model the non-linear relationship between rainfall and streamflow in the Pianco River Basin, in the Paraiba semiarid, using the technique of Artificial Neural Networks (ANN). Here the ability of ANN was evaluated to model the rainfall-runoff process on a monthly basis. During training of the ANN, the network architecture and weights initialization influence were considered. At the end of the training the best architecture was chosen, to model the streamflow monthly mean in the studied basin, based upon the performance of the model. The ANN architecture that produced the better result was RC315L with values for the determination coefficient, efficiency coefficient and standard estimate error (SEE) equal to 92.0, 77.0% and 8.29 respectively.

Influência da Urbanização no Clima da Cidade de Campina Grande-PB (Influence of Urbanization on Climate of the Campina Grande City–PB)

A expansao de cidades produz diversos impactos no ambiente urbano causado por atividades antropogenicas. Este estudo avaliou o efeito da urbanizacao no clima da cidade de Campina Grande com base em dados mensais de temperatura media do ar, precipitacao pluvial, umidade relativa do ar e insolacao no periodo de 1963 a 2004. O metodo de desvios cumulativos foi utilizado para detectar mudancas abruptas nas series temporais. Dois periodos de estudo foram estabelecidos: pre-urbano intenso PRE-UI (1963-1985) e pos-urbano intenso POS-UI (1986-2004). Para cada variavel climatica foram obtidas estatisticas como: medias, desvio-padrao, coeficiente de variacao (CV) e autocorrelacao serial. Foram avaliadas as diferencas entre as medias dos periodos PRE-UI e POS-UI atraves do teste de t-Student. Tambem foi usado o teste Mann-Kendall para avaliar as tendencias das series temporais no periodo total estudado. A temperatura media do ar apresentou tendencia crescente, enquanto umidade relativa apresentou tendencia decrescente, todas estatisticamente significativas ao nivel de 1% atraves do teste de Mann-Kendall. A serie de precipitacao pluvial nao apresentou tendencia estatisticamente significativa. A variabilidade da precipitacao pluvial intra-anual, expressa pelo CV, e muito alta e variou de 30 a 89% durante o periodo analisado. A variabilidade anual da precipitacao pluvial e cerca de 30% da variabilidade intra-anual. A temperatura do ar demonstrou persistencia natural atraves dos valores do coeficiente de autocorrelacao, para os primeiros lags. Palavras-chave: Clima urbano, Mann-Kendall e variaveis climaticas Influence of Urbanization on Climate of the Campina Grande City–PB ABSTRACT The expansion of cities produces different impacts in the urban environment caused by anthropogenic activities. This study evaluated the effect of urbanization on climate of the Campina Grande city based on monthly data of average air temperature, rainfall, relative humidity and sunshine in the period 1963 to 2004. The cumulative deviation method was used to detect abrupt changes in time series. Two study periods were established: intense urban pre-PRE-UI (1963-1985) and after intense urban POST-IU (1986-2004). For each climate variable, statistics were obtained as averages, standard deviation, coefficient of variation (CV) and serial autocorrelation. We evaluated the differences between the mean pre-and post-IU through the IU Student t test. It was also used Mann-Kendall test to assess trends in time series over the entire period studied. The average air temperature showed an ascending trend, while relative humidity showed a declining trend, all statistically significant at 1% through the Mann-Kendall test. The series of rainfall did not show a statistically significant trend. The variability of intra-annual precipitation, expressed as CV, is very high and ranged from 30 to 89% during the period analyzed. The variability of annual rainfall is about 30% of intra-annual variability. The air temperature showed persistence through the natural values the autocorrelation coefficient for the first lags. Keywords: Urban climate, Mann-Kendall and climatic variables

Uso de ferramentas estatísticas para acompanhamento climático e prevenção de riscos na bacia hidrográfica do Rio Mundaú (Brasil)

EnglishPrecipitation variations in the hydrographic basin of the Mundau river were studied using the rainfall anomaly index (RAI) and the wavelet analysis. The results showed that the El Nino-Southern Oscillation related interannual variability and the decadal variability influenced the local rainfall variability. portuguesAs variacoes da precipitacao na bacia hidrografica do rio Mundau foram estudadas utilizando o Indice de anomalia de chuva (IAC) e a Analise de Ondeleta. Os resultados mostraram que a variabilidade interanual ligada ao ciclo de El Nino Oscilacao Sul e a variabilidade decadal influenciaram na variabilidade pluviometrica local.

INFLUÊNCIA DA VARIABILIDADE CLIMÁTICA GLOBAL E DE SUAS ESCALAS TEMPORAIS SOBRE A PRECIPITAÇÃO NO ALTO MUNDAÚ (PE)

As variacoes da precipitacao em uma regiao da bacia hidrografica do rio Mundau foram estudadas utilizando o Indice de anomalia de chuva (IAC) e a Analise de Ondeleta. Esta tecnica envolve transformacao de uma serie unidimensional em um espaco de tempo e frequencia, permitindo determinar as escalas de variabilidade dominantes e suas variacoes temporais. Os resultados mostraram que a variabilidade da precipitacao e definida por multi-escalas temporais localizadas em certos intervalos de tempo. No entanto, a variabilidade interanual ligada ao ciclo de El Nino Oscilacao Sul e a variabilidade decadal influenciaram na variabilidade pluviometrica do Alto Mundau.

Study of the viability of water production by air cooling

Research carried out in the municipalities of Campina Grande and Sao Joao do Cariri prove the viability of the production of drinking water by the formation of the dew on cold surfaces of conventional refrigeration systems or on external surfaces of PET bottles containing ice. The experimental results presented here show that the cooling of air can produce enough quantity of water to minimize the consequences of shortage of drinking water in the semiarid zone of the Brazilian Northeast region. The experiment based on direct contact between the air and the cold surface of the refrigeration system produced dew at a rate of 1.23 L h-1 m-2. To obtain a liter of dew, the system consumes, on average, 0.75 kWh of electrical energy. The obtained results are satisfactory, considering that the experimental equipment used is quite simple.