graduate at Engenharia Civil from Universidade Federal da Paraíba (1990), graduate at Processamento de Dados (Campina Grande) from Universidade Federal da Paraíba (1991), master's at Engenharia Civil from Ehime University (1994) and ph.d. at Engenharia from Ehime University (1997). He is currently associate professor at Universidade Federal da Paraíba. Has experience in Civil Engineering, acting on the following subjects: modelagem hidrossedimentológica, erosão, modelagem vazão-erosão, runoff-erosion modeling and wavelet. Address: João Pessoa, Paraiba, Brazil
Este estudo avaliou a variação espaço-temporal da precipitação de 1970 a 2000, na Bacia do Rio Ta... more Este estudo avaliou a variação espaço-temporal da precipitação de 1970 a 2000, na Bacia do Rio Tapacurá, localizada no Estado de Pernambuco. Diversos parâmetros estatísticos foram utilizados para estudar a estrutura das séries de precipitação anual e mensal, tais como média, desvio padrão, desvio normalizado, linha de tendência e coeficiente de variação. O estudo em escala mensal mostrou que no período de março a julho ocorrem 60% da precipitação total anual, e que o período seco ocorre entre agosto e fevereiro. Na escala anual os resultados mostraram uma diminuição significativa das chuvas da ordem de -20% em relação à média histórica. Sobre a variabilidade espacial, constatou-se que a precipitação decresce no sentido leste-oeste, e que os períodos com menor volume pluviométrico possuem os maiores coeficientes de variação.
ABSTRACT Neste trabalho procurou-se quantificar os fluxos subsuperficial e superficial em um cana... more ABSTRACT Neste trabalho procurou-se quantificar os fluxos subsuperficial e superficial em um canal de alta declividade com uma camada de cascalho no leito, com a finalidade de relacionar as vazões com as características hidráulicas do canal. Nos cursos naturais de água com alta declividade, o leito é formado de uma grossa camada de cascalho e duas condições de escoamento podem ser observadas. A primeira, a condição mais comum, quando o fluxo fica confinado na camada de cascalho e a segunda, na ocorrência de cheia, quando a superfície da água fica bem acima da camada de cascalho. O comportamento hidráulico do leito de cascalho foi investigado experimentalmente e os resultados mostraram que para o escoamento através da camada de cascalho, a lei de Darcy precisa ser modificada para este tipo de meio poroso e a relação proposta por Stephenson parece ser bastante satisfatória. Para a segunda condição de escoamento, foi analisada a variação da resistência do leito de cascalho. A equação desenvolvida por Ugarte e Madrid, para o cálculo da resistência ao fluxo através da modificação do coeficiente n de Manning, e as equações de Hey e de Bathurst, para o coeficiente f de Darcy-Weisbach, foram avaliadas e essas equações mostraram-se ser satisfatórias em certas condições associadas do tamanho do material e da declividade do leito.
This study observed the thermal sensation perceptions of users in two public squares in the semia... more This study observed the thermal sensation perceptions of users in two public squares in the semiarid region of Paraíba state, northeastern Brazil. Two cities with contrasting microclimates were selected for this study: Teixeira and Patos, which present different climatic conditions despite their geographic proximity. The main topics addressed in this study are users’ perceptions and the climatic variables that influence their comfort level in central city public squares. In this study, field measurements were performed using a Davis meteorological station, and surveys were conducted in January (a dry month) and June (a wet month) in 2016. The users of the open spaces (squares) with trees were sampled by interviews lasting approximately 5 min. Statistical analyses of the correlation between the thermal perceptions and climatological station data at the time the answers were given were based on the real sensation vote index. The city of Patos presented an Effective Temperature Index Resulting from the Wind Effect (ETv) that ranged from partially comfortable to uncomfortable, with a thermal sensation of 27–28 °C in the hours between 12:00 and 14:00. In Teixeira, the level of thermal discomfort variation was constant (i.e., comfortable) for the dry month and ranged from comfortable to partially comfortable during the rainy month. The confidence interval of Patos was 26–35 °C air temperature, 20–71% relative humidity and up to 1.5 m/s wind speed; the corresponding values for Teixeira were 18–30 °C, 40–68% and up to 3.6 m/s. The results show the level of differentiation between the two months of the year for the two cities and reveal the perceptions of people in the two cities. In January, the population prefers a colder thermal environment, which indicates the necessity of maintaining shading and ventilation.
Dengue, a reemerging disease, is one of the most important viral diseases transmitted by mosquito... more Dengue, a reemerging disease, is one of the most important viral diseases transmitted by mosquitoes. In this study, 55,680 cases of dengue between 2007 and 2015 were reported in Paraíba State, among which, 30% were reported in João Pessoa city, with peaks in 2015, 2011 and 2013. Weather is considered to be a key factor in the temporal and spatial distribution of vector-transmitted diseases. Thus, the relationship between rainfall occurrence and dengue incidences reported from 2007 to 2015 in João Pessoa city, Paraíba State, Brazil, was analyzed by means of wavelet transform, when a frequency analysis of both rainfall and dengue incidence signals was performed. To determine the relationship between rainfall and the incidence of dengue cases, a sample cross correlation function was performed to identify lags in the rainfall and temperature variables that might be useful predictors of dengue incidence. The total rainfall within 90 days presented the most significant association with the number of dengue cases, whereas temperature was not found to be a useful predictor. The correlation between rainfall and the occurrence of dengue cases showed that the number of cases increased in the first few months after the rainy season. Wavelet analysis showed that in addition to the annual frequency presented in both time series, the dengue time series also presented the 3-year frequency from 2010. Cross wavelet analysis revealed that such an annual frequency of both time series was in phase; however, after 2010, it was also possible to observe 45° up phase arrows, which indicated that rainfall in the present year led to an increased dengue incidence the following year. Thus, this approach to analyze surveillance data might be useful for developing public health policies for dengue prevention and control.
Journal of Urban and Environmental Engineering, 2016
The rainfall characteristics within Klang River basin is analyzed by the continuous wavelet trans... more The rainfall characteristics within Klang River basin is analyzed by the continuous wavelet transform using monthly rainfall data (1997-2009) from a raingauge and also using daily rainfall data (1998-2013) from the Tropical Rainfall Measuring Mission (TRMM). The wavelet power spectrum showed that some frequency components were presented within the rainfall time series, but the observed time series is short to provide accurate information, thus the daily TRMM rainfall data were used. In such analysis, two main frequency components, i.e., 6 and 12 months, showed to be present during the entire period of 16 years. Such semiannual and annual frequencies were confirmed by the global wavelet power spectra. Finally, the modulation in the 8-16-month and 256-512-day bands were examined by an average of all scales between 8 and 16 months, and 256 and 512 days, respectively, giving a measure of the average monthly/daily variance versus time, where the periods with low or high variance could be identified.
Eco-environmental change prediction models are important decision tools for policy makers, as the... more Eco-environmental change prediction models are important decision tools for policy makers, as they help to quantify environmental sensitivity and to understand the relationship between human activities and environmental quality. Thus, this paper aims to analyze eco-environmental changes in Monteiro County, a semi-arid zone within northeastern Brazil between 1987 and 2010, by means of satellite images, geographic information system and global positioning system techniques, topographic map, climatic data and soil maps, as well as field survey. The resulting outputs were evaluated for their ability to accurately predict the most sensitive and least sensitive areas. The results showed that land cover changes have modified the environment in general and the land degradation and low soil loss processes were identified. The mean soil loss decreased from 9.67 t ha −¹ yr −¹ in 1987 to 2.67 t ha −¹ yr −¹ in 2010, as an effect of vegetation gain and particularly the conversion of thousands of square kilometers of Tropophile caatinga middle slope and barren land into Tropophile caatinga plain and Tropophile caatinga high strand. Thus, this study provides insight on territorial ordering and management of environmental services with a regional perspective. ABSTRACT
Trend analysis of monthly mean streamflows is essential for better water resources management and... more Trend analysis of monthly mean streamflows is essential for better water resources management and planning. In this study, Mann Kendall (MK), Sen’s method and Şen’s innovative trend method (ITM) were employed in order to examine the possible trends of monthly streamflows obtained from nine stations from three basins (Yakabasi and Derecikviran in Western Black Sea Basin; Durucasu, Sütlüce, Kale and Gomeleonu in Yesilirmak Basin; Şimşirli, Tozköy and Topluca in Eastern Black Sea Basin) located in Black Sea Region of Turkey. Based on the MK, streamflow data of Tozköy Station which is located in western part of the Eastern Black Sea Region showed a significantly increasing trend while a significantly decreasing trend was found for the Yakabasi, Derecikviran, Durucasu and Sütlüce stations which are situated in western part of the Black Sea Region. According to the Sen’s trend method, a significantly decreasing trend was seen in Durucasu, Sütlüce, Yakabasi and Derecikviran stations while Tozköy station showed significantly increasing trend. According to the ITM, low-medium values of Tozköy Station indicated slightly increasing trend while low and medium streamflow values of Yakabasi, Derecikviran, Durucasu and Sütlüce stations showed a decreasing trend. High streamflow values of Derecikviran and Sütlüce stations showed a decreasing trend while corresponding values of Yakabasi, Şimşirli and Tozköy stations indicated an increasing trend. It was showed that trends of low, medium, and high data can be easily identified by ITM which has some advantages (having no assumption such as serial relationship, non-normality, and, test number) over the Sen’s method and Mann-Kendall test.
International Journal of Environmental Science and Technology, 2018
Water scarcity and sediment yield scarcity are major environmental problems in the Brazilian semi... more Water scarcity and sediment yield scarcity are major environmental problems in the Brazilian semi-arid region that influence the quantity and quality of water used for water supply. Thus, the aim of the paper was to analyse the water balance and the sediment yield in the Epitácio Pessoa Dam river basin using the Soil and Water Assessment Tool model. Rainfall, streamflow, air temperature, air humidity data from 1970 to 1993, a soil type map, a land cover map, and a digital elevation model were used in this study. The model was calibrated and validated by comparing simulated mean monthly streamflow with observed long-term mean monthly streamflow for the Poço de Pedras and Caraúbas streamflow gauges after sediment yield values were estimated. The Soil and Water Assessment Tool model results indicated good performance by the model during the calibration, with an observed mean streamflow of 6.86 m 3 /s and a simulated streamflow of 5.68 m 3 /s for Poço de Pedras and 9.33 m 3 /s for Caraúbas. The mean sediment yield was 3.91 ton/ha/month. The results of the water balance analysis indicate a high rate of evapotranspiration in the basin (68% evapotranspiration), and 7% of the rainfall was converted to streamflow (5% streamflow and 2% base flow). Therefore, this study found that Soil and Water Assessment Tool could be effectively used for assessing the water balance components and sediment yield of the Epitácio Pessoa Dam river basin, Paraíba State, Brazil.
Combinations of low-frequency components (also known as approximations) resulting from the wavele... more Combinations of low-frequency components (also known as approximations) resulting from the wavelet decomposition are tested as inputs to an artificial neural network (ANN) in a hybrid approach, and compared to classical ANN models for flow forecasting for 1, 3, 6 and 12 months ahead. In addition, the inputs are rewritten in terms of the flow, revealing what type of information was being provided to the network, in order to understand the effect of the approximations on the forecasting performance. The results show that the hybrid approach improved the accuracy of all tested models, especially for 1, 3 and 6 months ahead. The input analyses show that high-frequency components are more important for shorter forecast horizons, while for longer horizons, they may worsen the model accuracy.
A novel wavelet-artificial neural network hybrid model (WA-ANN) for short-term daily inflow forec... more A novel wavelet-artificial neural network hybrid model (WA-ANN) for short-term daily inflow forecasting is proposed, using for the first time Tropical Rainfall Measuring Mission (TRMM) data together with inflow data, which were transformed using mother-wavelets to improve the model performance. The models were assessed using the inflow records to a Brazilian reservoir named Três Marias, located in the São Francisco River basin, and daily rainfall estimates from the TRMM both for the period of 1998-2012. Several combinations of inputs for both regular and hybrid artificial neural networks (ANN) were assessed to forecast inflows seven days ahead, and it was proved that the WA-ANN had a superior performance. Even the WA-ANN model, which uses only the approximation at level three of rainfall data, provided a higher performance than the regular ANN, which uses the raw inflow data [r increase 16%, Nash-Sutcliffe model efficiency coefficient (NASH) increase 35%, and root-mean-square deviation (RMSD) decrease 47%]. It was also found the best model was the WA-ANN with transformed rainfall and inflow data as input (r increase 20%, NASH increase 44%, and RMSD decrease 69%).
In Paraíba state, precipitation is strongly affected by several climate systems, such as trade wi... more In Paraíba state, precipitation is strongly affected by several climate systems, such as trade winds, the intertropical convergence zone (ITCZ), easterly wave disturbances (EWDs), and the South Atlantic subtropical high. Accordingly, the objective of this study was to analyze the spatiotemporal variability in precipitation to identify homogeneous trends of that variable and the effects of climate systems in Paraíba state by cluster analysis. The precipitation data used in this study derive from the Tropical Rainfall Measuring Mission (TRMM) satellite for the period from January 1998 to December 2015, and hierarchical clustering was used to classify the sites into different groups with similar trends. The findings show an uneven spatiotemporal precipitation distribution in all mesoregions of the state and considerable monthly precipitation variation in space. The estimated precipitation depth was highest in coastal regions and in high-altitude areas due to orographic precipitation. In general, the precipitation over Paraíba is characterized by strong gradients in the coastal zone towards the continent (Agreste, Borborema, and Sertão mesoregions) and from north to south due to the physiography of the region and the effects of climate systems with different time scales. Finally, the proposed clustering method using TRMM data was effective in characterizing climatic systems.
RESUMO – A erosão dos solos é um dos mais graves problemas ambientais em todo o mundo, principalm... more RESUMO – A erosão dos solos é um dos mais graves problemas ambientais em todo o mundo, principalmente em regiões semiáridas que sofrem com a variabilidade espaço-temporal da precipitação. Este artigo analisou os processos hidrossedimentológicos na Bacia do Rio Cobres, localizada na porção semiárida de Portugal, utilizando o modelo SWAT. Neste estudo foram utilizados dados diários de precipitação, temperatura, umidade do ar, vazão e produção de sedimentos, para o período de 1960 a 2000, mapas digitais de elevação do terreno com resolução espacial de 90 m, uso e ocupação do solo e tipos de solo da bacia. Os resultados demonstraram a eficácia do modelo na calibração da vazão, com Coeficiente de Determinação (R²) = 0,81 e Coeficiente de Nash-Sutcliffe (NS) = 0,63, e também para produção de sedimentos com R² = 0,62 e NS = 0,47. O Cenário 3 (Mata) apresentou o maior decréscimo na vazão média, em relação aos Cenários 1 (Real) e 2 (Pastagem). Conclui-se que o modelo SWAT acoplado ao SIG é uma ferramenta poderosa na análise espaço-temporal do comportamento dos processos hidrossedimentológicos. ABSTRACT – Effects of Scenarios of Land Use on Runoff and Sediment Yield for Cobres River Basin, Portugal. Soil erosion is a major environmental problem worldwide, mainly in semiarid regions that suffer with rainfall spatial and temporal variability. Thus, this paper analysed the runoff-erosion process at the Cobres River Basin, located in semiarid portion of Portugal, using the SWAT model. In this paper, rainfall, temperature and humidity data from 1960 to 2000, and digital maps of land cover, terrain digital elevation model with spatial resolution of 90 m, soil types were used. The results showed the effectiveness of the model for the runoff calibration, with R² = 0.81 and NS = 0.63, and also for sediment yield with R² = 0.62 and NS = 0.47. Scenario 1 (Forest) had the highest decrease in average streamflow, in relation to the Scenarios 1 (Real) and 2 (Pasture) scenarios. It is concluded that the SWAT model coupled to GIS is a powerful tool in the analysis of temporal and spatial behaviour of runoff-erosion processes.
Soil erosion is one of the most signifi cant environmental degradation processes. Mapping and ass... more Soil erosion is one of the most signifi cant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Universal Soil Loss Equation (USLE) using GIS tools to the Mamuaba watershed, southern Paraíba, for measuring soil erosion vulnerability. An annual rainfall erosivity map was derived from the geographical model adjusted for northeastern Brazil, calculating an annual value for each pixel. The factors of soil erodibility (K), the topography (LS), and land use and management (C) were obtained in a GIS environment from soil type maps, orbital images, and digital elevation model (DEM). The maps of the factors were combined to create the soil erosion vulnerability due to the water erosion. The results showed that, in general, the soils of the Mamuaba watershed present 84% of the area with values between 0 and 1 t ha-1 yr-1 , which could be classifi ed as " Slight to Moderate " vulnerability in 1989, and 77% of the area in 2013. In the upper region of Mamuaba watershed, the predominant classes were " Slight to Moderate " and " Moderate ". High values of soil losses were predominant in regions of Red-Yellow Acrisol covered by pasture. Furthermore, the integration of USLE/GIS showed to be an effi cient tool for the erosion prediction in this important basin of the Paraíba State. RESUMO A erosão do solo é um dos processos de degradação ambiental mais signifi cativos. O mapeamento e avaliação da vulner-abilidade do solo à erosão é uma importante ferramenta para o planejamento e gestão dos recursos naturais. O presente trabalho teve como objetivo a aplicação da Equação Universal de Perda de Solo (EUPS) com utilização de um SIG, na bacia do Rio Verde, sul de Paraíba, a fi m de avaliar a vulnerabilidade dos solos à erosão hídrica. O mapa do fator erosividade da chuva (R) foi desenvolvido a partir de um modelo geográfi co desenvolvido para o Nordeste do Brasil, sendo obtido em nível de pixel. Os fatores de erodibilidade dos solos (K), topográfi co (LS) e de uso e manejo (C) foram obtidos mediante mapas de tipos de solos, imagens orbitais e pelo modelo digital de elevação (MDE) em ambiente SIG. Os mapas dos fatores foram combinados por meio de álgebra de mapas, originando o mapa de vulnerabilidade dos solos à erosão hídrica. Os resultados mostraram que, em geral, os solos da bacia Mamuaba apresentam 84% da área com valores entre 0 e 1 t ha-1 yr-1, os quais podem ser classifi cados como vulnerabilidade " Leve a Moderado " para 1989, e 77% da área em 2013. Nas regiões de cabeceira, as classes predominantes foram " Leve a Moderado " e " Moderado ". Valores elevados de perda de solo foram predominantes em regiões com solos do tipo Argissolo Vermelho-Amarelo cobertos por pastagens. Além disso, a integração EUPS/SIG apresentou-se uma ferramenta efi ciente para a predição da erosão nesta importante bacia hidrográfi ca do estado de Paraíba.
Este estudo avaliou a variação espaço-temporal da precipitação de 1970 a 2000, na Bacia do Rio Ta... more Este estudo avaliou a variação espaço-temporal da precipitação de 1970 a 2000, na Bacia do Rio Tapacurá, localizada no Estado de Pernambuco. Diversos parâmetros estatísticos foram utilizados para estudar a estrutura das séries de precipitação anual e mensal, tais como média, desvio padrão, desvio normalizado, linha de tendência e coeficiente de variação. O estudo em escala mensal mostrou que no período de março a julho ocorrem 60% da precipitação total anual, e que o período seco ocorre entre agosto e fevereiro. Na escala anual os resultados mostraram uma diminuição significativa das chuvas da ordem de -20% em relação à média histórica. Sobre a variabilidade espacial, constatou-se que a precipitação decresce no sentido leste-oeste, e que os períodos com menor volume pluviométrico possuem os maiores coeficientes de variação.
ABSTRACT Neste trabalho procurou-se quantificar os fluxos subsuperficial e superficial em um cana... more ABSTRACT Neste trabalho procurou-se quantificar os fluxos subsuperficial e superficial em um canal de alta declividade com uma camada de cascalho no leito, com a finalidade de relacionar as vazões com as características hidráulicas do canal. Nos cursos naturais de água com alta declividade, o leito é formado de uma grossa camada de cascalho e duas condições de escoamento podem ser observadas. A primeira, a condição mais comum, quando o fluxo fica confinado na camada de cascalho e a segunda, na ocorrência de cheia, quando a superfície da água fica bem acima da camada de cascalho. O comportamento hidráulico do leito de cascalho foi investigado experimentalmente e os resultados mostraram que para o escoamento através da camada de cascalho, a lei de Darcy precisa ser modificada para este tipo de meio poroso e a relação proposta por Stephenson parece ser bastante satisfatória. Para a segunda condição de escoamento, foi analisada a variação da resistência do leito de cascalho. A equação desenvolvida por Ugarte e Madrid, para o cálculo da resistência ao fluxo através da modificação do coeficiente n de Manning, e as equações de Hey e de Bathurst, para o coeficiente f de Darcy-Weisbach, foram avaliadas e essas equações mostraram-se ser satisfatórias em certas condições associadas do tamanho do material e da declividade do leito.
This study observed the thermal sensation perceptions of users in two public squares in the semia... more This study observed the thermal sensation perceptions of users in two public squares in the semiarid region of Paraíba state, northeastern Brazil. Two cities with contrasting microclimates were selected for this study: Teixeira and Patos, which present different climatic conditions despite their geographic proximity. The main topics addressed in this study are users’ perceptions and the climatic variables that influence their comfort level in central city public squares. In this study, field measurements were performed using a Davis meteorological station, and surveys were conducted in January (a dry month) and June (a wet month) in 2016. The users of the open spaces (squares) with trees were sampled by interviews lasting approximately 5 min. Statistical analyses of the correlation between the thermal perceptions and climatological station data at the time the answers were given were based on the real sensation vote index. The city of Patos presented an Effective Temperature Index Resulting from the Wind Effect (ETv) that ranged from partially comfortable to uncomfortable, with a thermal sensation of 27–28 °C in the hours between 12:00 and 14:00. In Teixeira, the level of thermal discomfort variation was constant (i.e., comfortable) for the dry month and ranged from comfortable to partially comfortable during the rainy month. The confidence interval of Patos was 26–35 °C air temperature, 20–71% relative humidity and up to 1.5 m/s wind speed; the corresponding values for Teixeira were 18–30 °C, 40–68% and up to 3.6 m/s. The results show the level of differentiation between the two months of the year for the two cities and reveal the perceptions of people in the two cities. In January, the population prefers a colder thermal environment, which indicates the necessity of maintaining shading and ventilation.
Dengue, a reemerging disease, is one of the most important viral diseases transmitted by mosquito... more Dengue, a reemerging disease, is one of the most important viral diseases transmitted by mosquitoes. In this study, 55,680 cases of dengue between 2007 and 2015 were reported in Paraíba State, among which, 30% were reported in João Pessoa city, with peaks in 2015, 2011 and 2013. Weather is considered to be a key factor in the temporal and spatial distribution of vector-transmitted diseases. Thus, the relationship between rainfall occurrence and dengue incidences reported from 2007 to 2015 in João Pessoa city, Paraíba State, Brazil, was analyzed by means of wavelet transform, when a frequency analysis of both rainfall and dengue incidence signals was performed. To determine the relationship between rainfall and the incidence of dengue cases, a sample cross correlation function was performed to identify lags in the rainfall and temperature variables that might be useful predictors of dengue incidence. The total rainfall within 90 days presented the most significant association with the number of dengue cases, whereas temperature was not found to be a useful predictor. The correlation between rainfall and the occurrence of dengue cases showed that the number of cases increased in the first few months after the rainy season. Wavelet analysis showed that in addition to the annual frequency presented in both time series, the dengue time series also presented the 3-year frequency from 2010. Cross wavelet analysis revealed that such an annual frequency of both time series was in phase; however, after 2010, it was also possible to observe 45° up phase arrows, which indicated that rainfall in the present year led to an increased dengue incidence the following year. Thus, this approach to analyze surveillance data might be useful for developing public health policies for dengue prevention and control.
Journal of Urban and Environmental Engineering, 2016
The rainfall characteristics within Klang River basin is analyzed by the continuous wavelet trans... more The rainfall characteristics within Klang River basin is analyzed by the continuous wavelet transform using monthly rainfall data (1997-2009) from a raingauge and also using daily rainfall data (1998-2013) from the Tropical Rainfall Measuring Mission (TRMM). The wavelet power spectrum showed that some frequency components were presented within the rainfall time series, but the observed time series is short to provide accurate information, thus the daily TRMM rainfall data were used. In such analysis, two main frequency components, i.e., 6 and 12 months, showed to be present during the entire period of 16 years. Such semiannual and annual frequencies were confirmed by the global wavelet power spectra. Finally, the modulation in the 8-16-month and 256-512-day bands were examined by an average of all scales between 8 and 16 months, and 256 and 512 days, respectively, giving a measure of the average monthly/daily variance versus time, where the periods with low or high variance could be identified.
Eco-environmental change prediction models are important decision tools for policy makers, as the... more Eco-environmental change prediction models are important decision tools for policy makers, as they help to quantify environmental sensitivity and to understand the relationship between human activities and environmental quality. Thus, this paper aims to analyze eco-environmental changes in Monteiro County, a semi-arid zone within northeastern Brazil between 1987 and 2010, by means of satellite images, geographic information system and global positioning system techniques, topographic map, climatic data and soil maps, as well as field survey. The resulting outputs were evaluated for their ability to accurately predict the most sensitive and least sensitive areas. The results showed that land cover changes have modified the environment in general and the land degradation and low soil loss processes were identified. The mean soil loss decreased from 9.67 t ha −¹ yr −¹ in 1987 to 2.67 t ha −¹ yr −¹ in 2010, as an effect of vegetation gain and particularly the conversion of thousands of square kilometers of Tropophile caatinga middle slope and barren land into Tropophile caatinga plain and Tropophile caatinga high strand. Thus, this study provides insight on territorial ordering and management of environmental services with a regional perspective. ABSTRACT
Trend analysis of monthly mean streamflows is essential for better water resources management and... more Trend analysis of monthly mean streamflows is essential for better water resources management and planning. In this study, Mann Kendall (MK), Sen’s method and Şen’s innovative trend method (ITM) were employed in order to examine the possible trends of monthly streamflows obtained from nine stations from three basins (Yakabasi and Derecikviran in Western Black Sea Basin; Durucasu, Sütlüce, Kale and Gomeleonu in Yesilirmak Basin; Şimşirli, Tozköy and Topluca in Eastern Black Sea Basin) located in Black Sea Region of Turkey. Based on the MK, streamflow data of Tozköy Station which is located in western part of the Eastern Black Sea Region showed a significantly increasing trend while a significantly decreasing trend was found for the Yakabasi, Derecikviran, Durucasu and Sütlüce stations which are situated in western part of the Black Sea Region. According to the Sen’s trend method, a significantly decreasing trend was seen in Durucasu, Sütlüce, Yakabasi and Derecikviran stations while Tozköy station showed significantly increasing trend. According to the ITM, low-medium values of Tozköy Station indicated slightly increasing trend while low and medium streamflow values of Yakabasi, Derecikviran, Durucasu and Sütlüce stations showed a decreasing trend. High streamflow values of Derecikviran and Sütlüce stations showed a decreasing trend while corresponding values of Yakabasi, Şimşirli and Tozköy stations indicated an increasing trend. It was showed that trends of low, medium, and high data can be easily identified by ITM which has some advantages (having no assumption such as serial relationship, non-normality, and, test number) over the Sen’s method and Mann-Kendall test.
International Journal of Environmental Science and Technology, 2018
Water scarcity and sediment yield scarcity are major environmental problems in the Brazilian semi... more Water scarcity and sediment yield scarcity are major environmental problems in the Brazilian semi-arid region that influence the quantity and quality of water used for water supply. Thus, the aim of the paper was to analyse the water balance and the sediment yield in the Epitácio Pessoa Dam river basin using the Soil and Water Assessment Tool model. Rainfall, streamflow, air temperature, air humidity data from 1970 to 1993, a soil type map, a land cover map, and a digital elevation model were used in this study. The model was calibrated and validated by comparing simulated mean monthly streamflow with observed long-term mean monthly streamflow for the Poço de Pedras and Caraúbas streamflow gauges after sediment yield values were estimated. The Soil and Water Assessment Tool model results indicated good performance by the model during the calibration, with an observed mean streamflow of 6.86 m 3 /s and a simulated streamflow of 5.68 m 3 /s for Poço de Pedras and 9.33 m 3 /s for Caraúbas. The mean sediment yield was 3.91 ton/ha/month. The results of the water balance analysis indicate a high rate of evapotranspiration in the basin (68% evapotranspiration), and 7% of the rainfall was converted to streamflow (5% streamflow and 2% base flow). Therefore, this study found that Soil and Water Assessment Tool could be effectively used for assessing the water balance components and sediment yield of the Epitácio Pessoa Dam river basin, Paraíba State, Brazil.
Combinations of low-frequency components (also known as approximations) resulting from the wavele... more Combinations of low-frequency components (also known as approximations) resulting from the wavelet decomposition are tested as inputs to an artificial neural network (ANN) in a hybrid approach, and compared to classical ANN models for flow forecasting for 1, 3, 6 and 12 months ahead. In addition, the inputs are rewritten in terms of the flow, revealing what type of information was being provided to the network, in order to understand the effect of the approximations on the forecasting performance. The results show that the hybrid approach improved the accuracy of all tested models, especially for 1, 3 and 6 months ahead. The input analyses show that high-frequency components are more important for shorter forecast horizons, while for longer horizons, they may worsen the model accuracy.
A novel wavelet-artificial neural network hybrid model (WA-ANN) for short-term daily inflow forec... more A novel wavelet-artificial neural network hybrid model (WA-ANN) for short-term daily inflow forecasting is proposed, using for the first time Tropical Rainfall Measuring Mission (TRMM) data together with inflow data, which were transformed using mother-wavelets to improve the model performance. The models were assessed using the inflow records to a Brazilian reservoir named Três Marias, located in the São Francisco River basin, and daily rainfall estimates from the TRMM both for the period of 1998-2012. Several combinations of inputs for both regular and hybrid artificial neural networks (ANN) were assessed to forecast inflows seven days ahead, and it was proved that the WA-ANN had a superior performance. Even the WA-ANN model, which uses only the approximation at level three of rainfall data, provided a higher performance than the regular ANN, which uses the raw inflow data [r increase 16%, Nash-Sutcliffe model efficiency coefficient (NASH) increase 35%, and root-mean-square deviation (RMSD) decrease 47%]. It was also found the best model was the WA-ANN with transformed rainfall and inflow data as input (r increase 20%, NASH increase 44%, and RMSD decrease 69%).
In Paraíba state, precipitation is strongly affected by several climate systems, such as trade wi... more In Paraíba state, precipitation is strongly affected by several climate systems, such as trade winds, the intertropical convergence zone (ITCZ), easterly wave disturbances (EWDs), and the South Atlantic subtropical high. Accordingly, the objective of this study was to analyze the spatiotemporal variability in precipitation to identify homogeneous trends of that variable and the effects of climate systems in Paraíba state by cluster analysis. The precipitation data used in this study derive from the Tropical Rainfall Measuring Mission (TRMM) satellite for the period from January 1998 to December 2015, and hierarchical clustering was used to classify the sites into different groups with similar trends. The findings show an uneven spatiotemporal precipitation distribution in all mesoregions of the state and considerable monthly precipitation variation in space. The estimated precipitation depth was highest in coastal regions and in high-altitude areas due to orographic precipitation. In general, the precipitation over Paraíba is characterized by strong gradients in the coastal zone towards the continent (Agreste, Borborema, and Sertão mesoregions) and from north to south due to the physiography of the region and the effects of climate systems with different time scales. Finally, the proposed clustering method using TRMM data was effective in characterizing climatic systems.
RESUMO – A erosão dos solos é um dos mais graves problemas ambientais em todo o mundo, principalm... more RESUMO – A erosão dos solos é um dos mais graves problemas ambientais em todo o mundo, principalmente em regiões semiáridas que sofrem com a variabilidade espaço-temporal da precipitação. Este artigo analisou os processos hidrossedimentológicos na Bacia do Rio Cobres, localizada na porção semiárida de Portugal, utilizando o modelo SWAT. Neste estudo foram utilizados dados diários de precipitação, temperatura, umidade do ar, vazão e produção de sedimentos, para o período de 1960 a 2000, mapas digitais de elevação do terreno com resolução espacial de 90 m, uso e ocupação do solo e tipos de solo da bacia. Os resultados demonstraram a eficácia do modelo na calibração da vazão, com Coeficiente de Determinação (R²) = 0,81 e Coeficiente de Nash-Sutcliffe (NS) = 0,63, e também para produção de sedimentos com R² = 0,62 e NS = 0,47. O Cenário 3 (Mata) apresentou o maior decréscimo na vazão média, em relação aos Cenários 1 (Real) e 2 (Pastagem). Conclui-se que o modelo SWAT acoplado ao SIG é uma ferramenta poderosa na análise espaço-temporal do comportamento dos processos hidrossedimentológicos. ABSTRACT – Effects of Scenarios of Land Use on Runoff and Sediment Yield for Cobres River Basin, Portugal. Soil erosion is a major environmental problem worldwide, mainly in semiarid regions that suffer with rainfall spatial and temporal variability. Thus, this paper analysed the runoff-erosion process at the Cobres River Basin, located in semiarid portion of Portugal, using the SWAT model. In this paper, rainfall, temperature and humidity data from 1960 to 2000, and digital maps of land cover, terrain digital elevation model with spatial resolution of 90 m, soil types were used. The results showed the effectiveness of the model for the runoff calibration, with R² = 0.81 and NS = 0.63, and also for sediment yield with R² = 0.62 and NS = 0.47. Scenario 1 (Forest) had the highest decrease in average streamflow, in relation to the Scenarios 1 (Real) and 2 (Pasture) scenarios. It is concluded that the SWAT model coupled to GIS is a powerful tool in the analysis of temporal and spatial behaviour of runoff-erosion processes.
Soil erosion is one of the most signifi cant environmental degradation processes. Mapping and ass... more Soil erosion is one of the most signifi cant environmental degradation processes. Mapping and assessment of soil erosion vulnerability is an important tool for planning and management of the natural resources. The objective of the present study was to apply the Universal Soil Loss Equation (USLE) using GIS tools to the Mamuaba watershed, southern Paraíba, for measuring soil erosion vulnerability. An annual rainfall erosivity map was derived from the geographical model adjusted for northeastern Brazil, calculating an annual value for each pixel. The factors of soil erodibility (K), the topography (LS), and land use and management (C) were obtained in a GIS environment from soil type maps, orbital images, and digital elevation model (DEM). The maps of the factors were combined to create the soil erosion vulnerability due to the water erosion. The results showed that, in general, the soils of the Mamuaba watershed present 84% of the area with values between 0 and 1 t ha-1 yr-1 , which could be classifi ed as " Slight to Moderate " vulnerability in 1989, and 77% of the area in 2013. In the upper region of Mamuaba watershed, the predominant classes were " Slight to Moderate " and " Moderate ". High values of soil losses were predominant in regions of Red-Yellow Acrisol covered by pasture. Furthermore, the integration of USLE/GIS showed to be an effi cient tool for the erosion prediction in this important basin of the Paraíba State. RESUMO A erosão do solo é um dos processos de degradação ambiental mais signifi cativos. O mapeamento e avaliação da vulner-abilidade do solo à erosão é uma importante ferramenta para o planejamento e gestão dos recursos naturais. O presente trabalho teve como objetivo a aplicação da Equação Universal de Perda de Solo (EUPS) com utilização de um SIG, na bacia do Rio Verde, sul de Paraíba, a fi m de avaliar a vulnerabilidade dos solos à erosão hídrica. O mapa do fator erosividade da chuva (R) foi desenvolvido a partir de um modelo geográfi co desenvolvido para o Nordeste do Brasil, sendo obtido em nível de pixel. Os fatores de erodibilidade dos solos (K), topográfi co (LS) e de uso e manejo (C) foram obtidos mediante mapas de tipos de solos, imagens orbitais e pelo modelo digital de elevação (MDE) em ambiente SIG. Os mapas dos fatores foram combinados por meio de álgebra de mapas, originando o mapa de vulnerabilidade dos solos à erosão hídrica. Os resultados mostraram que, em geral, os solos da bacia Mamuaba apresentam 84% da área com valores entre 0 e 1 t ha-1 yr-1, os quais podem ser classifi cados como vulnerabilidade " Leve a Moderado " para 1989, e 77% da área em 2013. Nas regiões de cabeceira, as classes predominantes foram " Leve a Moderado " e " Moderado ". Valores elevados de perda de solo foram predominantes em regiões com solos do tipo Argissolo Vermelho-Amarelo cobertos por pastagens. Além disso, a integração EUPS/SIG apresentou-se uma ferramenta efi ciente para a predição da erosão nesta importante bacia hidrográfi ca do estado de Paraíba.
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