Navegando por Assunto "Chuvas"

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Acesso aberto (Open Access)
Análise da tendência de precipitação e vazão na bacia hidrográfica do Rio Amazonas
(Universidade Federal do Pará, 2022-02-24) DIAS, Luanna Costa; FERNANDES, Lindemberg Lima; http://lattes.cnpq.br/4641468846318922
Studying rainfall and flow trends is important to understand hydrological variability and to determine what has influenced increases or decays. The present study analyzes the trends of the space-time annual series of precipitation (total annual precipitation and maximum annual precipitation) and flow (averages, maximums and minimums) in the Amazon River Basin through non-parametric Mann-Kendall and Sen's tests. Slope for five different periods (1975-2014, 1980-2014, 1985-2014, 1995-2014 and 2000-2014). The results indicate that the series of average flows are increasing in the Amazon Basin for all analyzed periods. In the sub-basins of the right bank of the Amazon River, Tapajós and Madeira, the most recent period (2000-2014) registered the greatest trends of increase in the average annual flow from 1998 (year of strong El Niño) and that reached the largest values already observed. In the maximum flow series, the Óbidos station had an increasing rate of increase for the five periods analyzed for extreme flood events, which directly affect the population residing in these areas. Mean flow decay trends were found at six stations in the Tapajós and Madeira sub-basins. As for precipitation, there are significant trends of increase and decay distributed in several distinct regions of the basin. The stations with the highest positive precipitation trends had a significant increase since 1997, reaching the highest peaks in 2013. The comparison of the magnitude of the trends by the Sen's Slope test shows that there is a behavior of increasing flow rates in the entire Amazon basin and in terms of precipitation there are areas of increase and decrease, that is, precipitation is not the only variable that influences the flows of the Amazon River basin.
Acesso aberto (Open Access)
Análise da variabilidade pluviométrica da região da UHE – Tucuruí/PA no período operacional (1988-2017)
(Universidade Federal do Pará, 2020-01-30) ALMEIDA, Denilson Freitas; ISHIHARA, Júnior Hiroyuki; http://lattes.cnpq.br/3498874642887006; https://orcid.org/0000-0002-0081-7913
The Tocantins - Araguaia hydrographic region has become a major power in the generation of hydraulic energy with the installation of large hydroelectric plants and the formation of several artificial lakes, resulting in hydrological changes and possible changes in the microclimate and rainfall. The analysis of rainfall behavior in the hydrographic basin becomes of fundamental importance for the management of water resources. In order to subsidize the management and planning of water resources in the region, an analysis of the spatial-temporal rainfall variability was carried out in the Lake HPP-Tucuruí / PA region, being divided into 4 quadrants (NE, NO , SO and SE) and 12 sub-areas (NE50, NE100, NE200, NO50, NO100, NO200, SO50, SO100, SO200, SE50, SE100 and SE200), considering the period of 30 years (1988-2017), in order to analyze the behavior of the rains in the region. To this end, data were collected and analyzed from 30 pluviometric stations that appear in the database of the ANA platform (HidroWeb base), within a radius of up to 200 km from the hydroelectric plant. With the aid of the QGIS 3.0.3 software, the isohyets maps were drawn using the linear ordinary kriging interpolation method, representing the heights of the water slides. The results showed variability in the spatial and temporal distribution of the total volume precipitated in the referred period of study, identified in the results of standard deviation and variance, in addition to the result of the trend of rains by Mann Kendall's non-parametric tests. The pluviometric indexes showed decreases, when analyzing the entire study area, with an average rainfall of 2157.73 mm. There was a greater decrease in precipitation in the southern part of the region, which showed lower rainfall. In the northern regions, where the artificial lake formed by the Tucuruí dam is found, there were higher rainfall averages. The Mann-Kendall (MK) results showed a greater decrease in the quadrants of the microscale (close to the bus), especially at NO50, which showed a significant trend of decreasing rainfall in the study region (Z = -2.24).
Acesso aberto (Open Access)
Análise do comportamento da precipitação e da vazão em bacias hidrográficas Amazônicas
(Universidade Federal do Pará, 2016-03-14) HACHEM, Bruno Penna; FERNANDES, Lindemberg Lima; http://lattes.cnpq.br/4641468846318922
The aim of this study was to analyze the behavior of precipitation and flow in two river regions of the state of Pará, where Northern Corridor and Coast Northeast Atlantic. Both have the same rainfall and physical properties of the bowls are similar, being different only in regard to level and vegetable preservation area. For this study, we used 7 gauged stations and 7 rainfall in the Northern Corridor and 6 fluviometric 6 and rainfall in Costa Northeast Atlantic. After collecting the data in HIDROWEB, they were organized in Microsoft Excel spreadsheets software for application of Mann Kendall and Spearman tests, which stated that there is no trend in the series analyzed (α=5%). Was detected that the density of fluviometric and rainfall stations is low , according to the thresholds established by WMO. The Pearson correlation coefficients showed up "strong" between precipitation and flow of the areas studied, which also suffer influence of climatic phenomena (El Niño and La Niña). It was possible to consider that in the most preserved region, the time lag between the maximum rainfall and the maximum flow rate averaged two months, while the region with greater human action this time was an average of 1 month.
Acesso aberto (Open Access)
Avaliação da qualidade de água do sistema de aproveitamento de água da chuva instalado no Campus de Belém da Universidade Federal do Pará
(Universidade Federal do Pará, 2017-09-18) PACHECO, Paulo Rodrigo da Costa; TEIXEIRA, Luiza Carla Girard Mendes; http://lattes.cnpq.br/9773700229115395
This research has main objective to analyze the rainwater quality in an experimental unit of rainwater harvesting and treatment (EURHT) with emphasis on the treatment by filtration in two different filters: sand plus activated carbon of açaí seed (mixed) and activated carbon of açaí seed. The research was developed in three steps: 1) installation of the two filters and characterization of the filter composition; 2) rainwater quality monitoring of EURHT, considering the variables: apparent color, turbidity, electrical conductivity, pH, total alkalinity, total coliforms and E.coli, and the investigation of the presence of microorganisms in the tank; 3) evaluation of the costs involved in the implementation of the system, considering two filtration alternatives. The sand had effective diameter of 0.62mm, uniformity coefficient of 1.42 and specific gravity of 2,632 kg/m3. Activated carbon had an effective diameter of 1.8mm, coeficiente uniformity of 0.58, a humidity of 2.10%, and density of 0.358 g/cm3. Activated carbon filter had a flow rate of 0.35 m³/h, higher than the mixed filter (0.20 m³/h), even as the filtration rate was higher (34.26 m³/m2.d) and the Mixed filter of 19.19 m³/m2.d. The roof contributed to rainwater quality degradation, increasing the values of apparent color, turbidity, electrical conductivity and total alkalinity in relation to atmospheric water, which was already expected; The self-cleaning didn’t had a proptious performance, because there was increase in the variables value apparent color, turbidity, total coliforms and E. Coli in relation to water collected after the roof; The tank was the part of system that best contributed to the improvement of rainwater quality, because there was a decrease in the variables value apparent color, turbidity and electrical conductivity in relation to water after self-cleaning; The mixed filter and the activated carbon filter didn’t had a proptious performance, because decrease the water quality arriving from the tank for all variables. The mixed filter get better results than activated carbon filter. The mixed filter was also the best financial alternative in the system. In the tank were found about 7 different microorganisms, between them: zooplankton, algae frustules and fungal spores. EURHT didn’t produce rainwater for drinking purposes, because there were pathogenic microorganisms, besides values of variables above the limit of the ordinance 2914 (BRASIL, 2011), and there is a requirement for disinfection at end of the treatment process.
Acesso aberto (Open Access)
Condições termodinâmicas de eventos de precipitação extrema em Belém-PA durante a estação chuvosa
(2012-07) TAVARES, João Paulo Nardin; MOTA, Maria Aurora Santos da
The thermodynamic conditions from any region are very important to the development of the deep, moist convection, mainly in the tropical region. Therefore, the aim of this work was to understand and characterize the role of atmospheric thermodynamic conditions during extreme rainfall events in the rainy season, in Belém (PA, Brazil). The results show that the extreme rainfall, in their majority (56%) present a pre-storm environment with strong instability, indicated by the CAPE high values (above 1000 J/kg) and meaningful values of the instability indexes. There was, however, events with low values of CAPE in the 1200 UTC sounding at the day of the event, but larger values in the day before, which indicates that the rain in question may have begun in the early hours and have last for several hours, crossing the time of the sounding, explaining the decrease of this parameter. The K, TT and LI instability indexes showed a close representation of the environment, predicting storms with heavy rainfall with 74% of correct identification, if taken into account the events on which all indexes showed the same indication of strong instability. Therefore, thermodynamic conditions of strong instability may lead to storms, but are not the only responsible factors for convective storms with extreme rainfall
Acesso aberto (Open Access)
Erosividade da chuva em Rondon do Pará, PA, Brasil de 1999 a 2015 e projetada para 2035
(Universidade Federal do Pará, 2016-12) ROSA, Amanda Gama; SOUSA, Adriano Marlisom Leão de; COSTA, Jamer Andrade da; SOUZA, Everaldo Barreiros de
This study determined the rainfall erosivity value for the urban area of Rondon do Pará in order to provide information about the city's soil loss. The study also determined the probability of erosion occurrence and the return period projected for the next 20 years. The annual distribution of the erosivity index was analyzed and an estimate was made of the correlation between the average monthly erosivity index and the rainfall coefficient. To accomplish this, two types of rainfall data were obtained: 1) data observed by the CMORPH satellites from 1999 to 2015; and 2) data modelled by the RegCM4 model from 2016 to 2035. Erosivity was calculated based upon these monthly and annual rainfall data. Frequency distributions of erosivity values and their return periods were calculated and probability curves were plotted. Regression analyses between precipitation and erosivity were completed. In the period from 1999 to 2015, the value of the R factor of Rondon do Pará was 16,390 MJ mm ha-1h-1ano-1, with a probability of 47% of being equaled or exceeded at least once each 2.1 years. In the period from 2016 to 2015, the R value was 13,038 MJ mm ha-1h-1year-1. Highest soil losses are probable between February and January from 1999 to 2015 and between January and April from 2016 to 2035. The regression mathematical models that had the best results were the potency and the polynomial models for the years from 1999 to 2015 and 2016 to 2035, respectively.
Acesso aberto (Open Access)
Evento extremo de chuva-vazão na bacia hidrográfica do rio Araguari, Amapá, Brasil
(Universidade Federal do Pará, 2014-12) CUNHA, Alan Cavalcanti da; VILHENA, Jefferson Erasmo De Souza; SANTOS, Eldo Silva Dos; SARAIVA, Jaci Maria Bilhalva; KUHN, Paulo Afonso Fischer; BRITO, Daímio Chaves; SOUZA, Everaldo Barreiros de; ROCHA, Edson José Paulino da; CUNHA, Helenilza Ferreira Albuquerque; BRITO, Alaan Ubaiara; BRASIL JUNIOR, Antonio Cesar Pinho; PACA, Victor Hugo da Motta; SANTOS, Paula Verônica Campos Jorge
The objective of this investigation was to analyse the extreme river flows which have occurred between 9 and 14 April 2011 in the Rio Araguari-AP. The methodology consisted of three main steps: 1) re-analysis of precipitation estimated by the BRAMS (Brazilian Development in Regional Atmospheric Model System) model using the synoptic of the same period as support, 2) analysis of streamflow in sections of hydrological monitoring in Porto Platon, Capivari and Serra do Navio (ADCP-Accustic Profiller Doppler Current); 3) statistic analysis of the time series of maximum river flows in Porto Platon using Gumbel distribution. It was observed that the BRAMS system partially captured the standard precipitation when compared with the synoptic analysis and literature data, but the extreme hydrological responses representation still needs an optimization. In Porto Platon a flow record of 4036 m3 /s was recorded, whose behavior was analyzed from the perspective of the available monitoring mechanisms in the State. It was concluded that such extreme events are poorly detectable and offer considerable risks to users of the basin. The stream flow prediction based on available hydrological series was 100 years recurrence, but the analysis have revealed that this period would be 360 years, indicating significant deficiency of the prediction system of extreme events in the State.
Acesso aberto (Open Access)
Eventos extremos de precipitação em Belém-PA: uma revisão de notícias históricas de jornais
(2015-03) CAMPOS, Thamiris Luisa de Oliveira Bradão; MOTA, Maria Aurora Santos da; SANTOS, Sergio Rodrigo Quadros dos
This study examined the socioeconomic impacts of Daily Extreme Precipitation Events (hereafter "DEPEs") in Belem-Pará during the period 1987-2009. The DEPEs were characterized as "extreme" using the Decile technique. The objective of the study was to identify the consequences and the main neighborhoods affected by these events. The years influenced by occurrences of El Niño or La Niña had the lowest or the highest rates of DEPEs, respectively, and as well as the number of articles published in the city's newspapers. The monthly variation showed that the DEPEs and resulting newspaper articles were higher in the "wettest" (summer / austral autumn) period. The newspaper articles indicated that street flooding is the main consequence of DEPEs in the city of Belém-Pará, and that the most affected districts are Cremação, Jurunas and Batista Campos. These neighborhoods are near to one another and are all located in the Travessa Quintino Bocaiúva watershed, which has a low slope that delays the flow of water, favoring flooding. The city's lack of infrastructure is the main reason for the severe consequences of DEPEs.
Acesso aberto (Open Access)
Interações entre nuvens, chuvas e a biosfera na Amazônia
(Instituto Nacional de Pesquisas da Amazônia, 2005-06) DIAS, Maria Assunção Faus da Silva; COHEN, Júlia Clarinda Paiva; GANDU, Adilson Wagner
A review of results obtained within the Physical Climate component of LBA with respect to the interaction between the biosphere and cloud and rain formation in the Amazon Basin, in different seasons and different regions within the Basin is presented. The deforestation effect and the effect of biomass burning are discussed and the physical processes highlighted based on the data collected in several LBA intensive field campaigns. The complex interactions and the progress in the understanding their evolution based on the new datasets is presented.
Acesso aberto (Open Access)
Precipitação sazonal sobre a Amazônia oriental no período chuvoso: observações e simulações regionais com o RegCM3
(2009-06) SOUZA, Everaldo Barreiros de; LOPES, Marcio Nirlando Gomes; ROCHA, Edson José Paulino da; SOUZA, José Ricardo Santos de; CUNHA, Alan Cavalcanti da; SILVA, Renato Ramos da; FERREIRA, Douglas Batista da Silva; SANTOS, Daniel Meninéa; CARMO, Alexandre Melo Casseb do; SOUSA, José Raimundo Abreu de; GUIMARÃES, Paulo Lima; MOTA, Maria Aurora Santos da; MAKINO, Midori; SENNA, Renato Cruz; SOUSA, Adriano Marlisom Leão de; MOTA, Galdino Viana; KUHN, Paulo Afonso Fischer; SOUZA, Paulo Fernando de Souza; VITORINO, Maria Isabel
This paper presents a contribution on the climate modelling studies with emphasis on seasonal rainfall variability in eastern Amazonia, during the austral summer and autumn seasons (DJF and MAM). Based on RegCM3 regional climate simulations for a 26 years period (1982/83 to 2007/08) using high resolution domain scale (30 km) and two different convection schemes (Grell and MIT), it was investigated the model performance to simulate the regional pluviometric distribution in eastern Amazon, with reference to a new observational data base containing regional aspects extracted from a dense rain gauge station network. The quantitative analysis showed that RegCM3 presents systematic errors, especially those related to the dry bias in the Amapá and north/northeast of Pará using both schemes Grell and MIT, which indicate that the model does not reproduce ITCZ characteristics over equatorial Atlantic. The simulations using MIT also indicated wet bias in the southwest/south/southeast of Pará and north of Tocantins. Moreover, through composites technique, it was also investigated RegCM3 response to reproduce the anomalous spatial rainfall patterns in association with ENSO episodes and interhemispheric SSTa gradient phases across the intertropical Atlantic. The results showed that the model represented realistically well the spatial pattern related to the rainfall anomalies above (below) than normal in most of eastern Amazonia, during the known favourable scenarios, i.e., La Niña and south Atlantic SSTa gradient (unfavourable, i.e., El Niño and north Atlantic SSTa gradient).
Acesso aberto (Open Access)
Regionalização de precipitações via fuzzy C-means
(Universidade Federal do Pará, 2017-04-05) GOMES, Evanice Pinheiro; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The knowledge of the precipitation behavior is indispensable, since any change in its quantity and spatial and temporal distributions have an important impact on nature and consequently on the various human activities. However, in precipitation studies, the lack of rainfall monitoring, generating the lack of information over time and spatially in the river basins is a problem for the understanding of this variable. In order to overcome this problem, the rainfall regionalization method was proposed. The main idea was to divide the Tocantins Araguaia - RHTA hydrographic region into homogeneous regions, defined by the Fuzzy C-means method. The Euclidean distance was adopted as a measure of similarity and the fuzzification parameter, ranging from 1.2 to 2.0, and the explanatory variables of rainfall (altitude, latitude and longitude) were used as input data. Three homogeneous regions were obtained, which were validated by the PBM index and the heterogeneity test. The frequencies of observed rainfall events were generated for the 83 rain gauge stations, distributed in their respective regions, and calibrated by the Normal, Log-Normal, Gama, Gumbel, Exponential, Logarithmic and Weibull probability functions. With the application of the chi-square test, we defined the best probability function in the occurrence of rainfall in each homogeneous region. The validation of the probabilities functions was performed in 9 target stations, using the chi-square test. In this stage, it was observed that for annual average precipitation, data adherence occurred to all the rain gauge stations, since they presented results of the chi-square test of less than 5.99 (for Log-normal distribution functions). It was also observed that for monthly average precipitation, data were adhered to all the rainfall stations with the Gama and Weibull functions. For the simulation of rain depth, Linear, Potential, Exponential and Logarithm models were tested through the multiple regression method, using as independent variables, altitude, latitude and longitude. As performance criterion of the models, the R², R²_a, E%, ε%, NASH and RMSE were used. In the simulation of annual averages, the Linear model presented the best performance indices. In the estimation ofviii monthly averages, all multiple regression models did not perform well, with errors above 50%, which motivated the estimation of monthly rainfall for rainy and dry periods. In this new approach the regression models presented excellent performance criteria with errors below 10%. The performance indexes allowed us to conclude that the regional models developed for the homogeneous regions of rainfall, defined by the Fuzzy C-Means method, are a good option in the estimation of annual and monthly average rainfall and are important for a better understanding of the rainfall regime in RHTA, and can serve as a tool for better planning of water resources in the region.
Acesso aberto (Open Access)
Regionalização e estimativa de chuvas do estado do Pará
(Universidade Federal do Pará, 2014-04-25) GONÇALVES, Mariane Furtado; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
In Amazon region, a factor which prevents the most comprehensive knowledge of water resources is the lack of hydrological data (flow and precipitation) of small and medium-sized watersheds. This is mainly due to size of the region, which increases the costs of implementation and operation of the network. In this context, this work aims to develop a model of regionalization and estimated rainfall for the state Pará For this, we applied a methodology for delineation of homogeneous regions of precipitation through the cluster analysis was then determined probability of rain for some point rainfall homogeneous region obtained with the cluster analysis by applying probability functions, and finally was given estimates of rainfall heights, using multiple. For every step we used annual and monthly averages precipitation of a time series of 31 years (period 1960-1990), obtained at the Center for Climatic Research, Department of Geography, University of Delaware, Newark site, DE, USA. Among the analyzed years, years were selected with the occurrence of El Niño and La Niña. Using the agglomerative hierarchical Ward method, having as similarity measure the Euclidean distance for annual and monthly rainfall averages six homogeneous regions of precipitation were found, except for monthly averages for rainfall series with the occurrence of El Niño and La Niña, who has four and five homogeneous regions, respectively. After the definition of homogeneous regions, probability models (Normal, Gumbel and Exponential) were fitted to determine the heights of the three sequences of rainfall time series, applied the chi-square test for this check. After the calibration step to annual rainfall, it was found that the model is best fit normal distribution the probability of exceedance observed, since average monthly precipitation for the Gumbel distribution model got better grip frequencies of exceedance. The above models were validated using the rainfall series of 12 stations of the Agência Nacional de Água (ANA), considered as target stations. At this stage, it was observed that to mean annual rainfall occurred adherence of the data to all the rainfall stations targeted because they presented the results of applying the chi-square test less than 3.84 (for normal distribution functions). And it was also found that for average monthly rainfall, there was adherence of the data to all the rainfall stations target. To simulate rainfall heights were tested for calibration models of power, according to Power and Linear model by means of multiple regression. As a criterion of performance models, the percentage relative error was used. For time series containing series every year and with the occurrence of La Niña, the model showed a lower relative. As for series with the occurrence of El Niño, the model of power had minor errors. As for the probabilistic models, the calibration results of the multiple regression models were validated with the use of rainfall stations of the ANA. In the validation step for series containing every year the percentage errors ranging from 0.2 to 39.2%, as when used in El Niño years there has been an increase in error ranging from 1.9 to 54.8%, and La Niña years from 8.5 to 55.9%. Although some estimates have had considerable errors, above 50%. The results of applying this methodology are important for a better understanding of rainfall in the state of Pará and the Amazon, and can serve as a tool for better planning and management of water resources in the region.
Acesso aberto (Open Access)
Variabilidade da precipitação em tempo e espaço associada à Zona de Convergência Intertropical
(2012-12) MOURA, Mauricio do Nascimento; VITORINO, Maria Isabel
This study aims to present an atmospheric analysis of spatial and temporal variability of the Intertropical Convergence Zone (ITCZ) in Belem, Jakarta and Nairobi, which are located on the continents of South America, Asia and Africa, respectively. For this, daily precipitation and observed long wave radiation data for the period 1999 to 2008 were used, and mathematical and statistical techniques, such as the arithmetic mean and the Morlet wavelet transform were applied. In general, the results indicate that spatially, the month rainfall varies considerably, since that the three studied cities are located far apart in different continents in the tropical zone. This occurs mainly during the months from January to May, period of greatest activity of the ITCZ in the southern hemisphere. The atmospheric variations observed from the phase wavelet scalograms indicate that the interdecadal scales, annual, interannual and intraseasonal scales are rainfall modulators. Such scales can be represented by the ocean-atmosphere phenomenon mechanisms of El Niño Southern Oscillation and intraseasonal oscillation of Madden and Julian. The contribution of these phenomena to the rainfall distribution over these regions is evident during the study period, and Nairobi, in spite of being located at latitude similar to that of Belem, shows low evidence of the annual cycle and high at interdecadal scale. In the case of Belem and Jakarta oscillations at multiscale rainfall concentrated in the mechanisms scales that modulate the rain associated with the annual cycle and intraseasonal cycle during the period.