Navegando por Assunto "Raios"

Agora exibindo 1 - 11 de 11

Acesso aberto (Open Access)
Características e distribuição das descargas atmosféricas e dos sistemas precipitantes produtores de raios na Amazônia Oriental
(Universidade Federal do Pará, 2010) TEIXEIRA, Venize Assunção; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271; MOTA, Galdino Viana; http://lattes.cnpq.br/8821024246942574
This study analyzed 10 years of spatial and temporal distribution of lightning and precipitation systems and their characteristics such as reflectivity, brightness temperature and height of the precipitation systems sampled by the Lightning Imaging Sensor (LIS), Precipitation Radar (PR) e TRMM Microwave Imager (TMI) sensors onboard of the Tropical Rainfall Measuring Mission (TRMM) satellite. This dataset is organized and stored by the research group of tropical convection of the University of Utah from December 1997 to February 2009. This work also analyzes data from outbreaks of fires detected by INPE in the period 1998 to 2008. It was selected an area bounded between 60°W to 45°W of longitudes and between 10°S to 5°N of latitudes, which was subsequently divided into nine sub-areas for more detailed information. To investigate the possible influence of burning in the number of lightning flashes, we selected eight areas, in which four present the highest number of fire outbreaks and four with the lowest ones. The precipitation systems were classified according to the method of Nesbitt et. al (2000), and obeying the new definition of the data proposed by Liu (2007). The precipitation features used in this work are named ALLPFS, which are all systems with rainfall pixels estimated by the 2A25 algorithm. These systems have the categories of PFS (present information of brightness temperature) and OTHPFS (without information of brightness temperature). Within the PFS, the systems are defined as those without ice signature (NOICE), with ice signature (WICE) and mesoscale convective systems (MCS). The most intense MCSs are defined as IMCS. The results show that the southern regions of Pará, around Belém and Marajo Island were the ones with the highest occurrence of lightning in the Amazon region, with values exceeding 20 to 35 lightning flashes/ km²/year. The NOICE systems were equally frequent in all regions. The categories WICE and MCS are those which contribute most to the production of lightning over these regions. It was also observed that the electrified systems have great contribution to the estimated amount of rainfall over central and southern parts, with percentages above 50% in the area SOUTH. The monthly variation of the lightning occurrence densities in the studied area showed that the highest occurrence of lightning was found over the city of Belem during the months from January to June, peaking in January. The highest occurrences in the southern sector of eastern Amazonia were concentrated in the months of September to December. In the analysis on the interaction between lightning and burning spot areas, it was not possible to verify a consistent correlation between lightning and fires, showing that despite the large number of fires observed on these areas, other factors influence the production of lightning flashes.
Acesso aberto (Open Access)
Distribuição de raios, precipitação e casos de tempestades severas na Amazônia Oriental
(Universidade Federal do Pará, 2010) RIBEIRO, Wanda Maria do Nascimento; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
The objective of this work was to analyze the relation between lightning and precipitation, over different land surfaces and through case studies of severe storms, during the period of December, 2006 to December 2008. The studies were carried out within an area limited by the geographic coordinates 0°S to 6°S and 47°W to 50°W, which includes parts of the States of Pará and Maranhão, as well as, the northern portion, of Tocantins State, in Brazil. This region was selected for study, due to its location within the core area of the sensor locations of the lightning detection network operated by the Amazonian Protection System (SIPAM-LDN), which covers most of the electric power transmission lines in eastern Amazonia. Rainfall data were collected by 46 digital pluviometers, belonging to meteorological stations of INMET and HIDROWEB-ANA. For the analysis of the days of severe storms, data from a high time resolution pluviometer, operated by CPRM in Belem, were also used. In order to classify the land surface types, in particular the vegetation cover, information from IBGE Natural Resources data library, were used. For more detailed analysis of the relations among lightning, precipitation and land surface types, the studied area was divided in three parts, with different physiographic characteristics. Area 1, including the Marajo Island and a large water surface at the mouth of the Amazon River and nearby Atlantic Ocean. Area 2, which has 60% of its surface covered by forests. Area 3, with 62% of its surface covered by agriculture and/or pasture areas. Large scale meteorological systems which produce lightning and rainfall were taken into account for the analyses over these 3 sub areas, as well as, for the severe storm case studies around Belem. In almost all storms studied, it was observed that the lightning onset of events preceded the intense rainfall. In general, the results showed some seasonally different behaviors of the lightning density of occurrences over these distinct land surface compositions. Nevertheless, this work also showed that, the meteorological conditions have larger influence on the values of this variable than the surface types . This was clearly demonstrated by the case studies of severe storms, when the ZCIT and LI`s proved to be determinant on the precipitation and lightning occurrences observed around Belem.
Acesso aberto (Open Access)
Elementos de sensores de eletricidade atmosférica
(Universidade Federal do Pará, 2010-05-18) PEREIRA, Carlos Simões; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
The electromagnetic environment surrounding the planet Earth has a fundamental role in the preservation and development of the living creature, and perhaps the last frontier of human knowledge to be dominated completely, before we ventured to the space outside in search of new opportunity outside. This environment is only now being tamed and best known, and this endeavor has as lynch pin the use of appropriate sensors that can detect and quantify these electrical effects, to serve as a basis for the generation of theories, to explain the underlying phenomena, including in this, the sensors of atmospheric electricity. This work intends to make a comprehensive analysis of these sensor’s systems of atmospheric electricity in use today, evaluating their models of operation, its limitations and its intelligence, and producing a summarized basic specifications for development of better sensors and setting standards for metric types of the variables to be measured, to cope with the currents and future demands in this field of knowledge. Additionally, the processes involved in the calibration of these sensors will be addressed with a review of computational model based on the method of moments (MoM) and other that my be used for evaluation of electromagnetic fields emitted by remote charges patterns and electrical currents, which serve to support and basis for these calibrations.
Acesso aberto (Open Access)
Influência de sistemas meteorológicos de grande escala sobre a distribuição de raios na Amazônia Oriental, com aplicação no setor elétrico
(Universidade Federal do Pará, 2010) SANTOS, Alex de Assis Santos dos; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
A study was made of the relationship between lightning occurrence density distribution and their associated meteorological conditions over an area in eastern Amazon region. In order to do that, special programs were developed to statistically process lightning data, as well as, to generate lightning occurrence density maps on a geographical grid, for different time intervals. Using these methods an application analysis was performed to determine “spots” of high lightning frequency of occurrences along electric power transmission lines, in order to offer subsidies for the protection and operation of these electric systems in the region. Lightning data from the Amazonian Protection System (SIPAM) lightning detection network were used to upgrade the detection efficiency of the intercontinental STARNET system, and obtain more uniform and realistic lightning density maps over the limits of 0º to -10º of latitude and -53º to -43º of longitude. These maps were interpreted at weekly and seasonal periods, considering the simultaneous observations of rainfall, wind, long wave radiation (LWR) and the presence of large scale, the Intertropical Convergence Zone and South Atlantic Convergence Zone (ITCZ, SACZ) meteorological systems, acting over the area of study. The results showed good correlation among the areas of intense convection, determined by the convergence of winds and negative LWR anomalies and high lightning activity both for ITCZ and SACZ configuration over the area. Lightning activity also coincided, with a few exceptions, with the areas of higher weekly precipitation. It was observed also that during a dry trimester the transmission lines segment of Mojú-Tailândia and Jacundá-Marabá presented significantly higher incidence of lightning over them. During a rainy quarter the lightning density of currences was, overall, 86% higher and more evenly distributed than during the equivalent drier period, over the area considered. Density maxima of lightning occurrences reached values of 18 events/km2/trimester, at some spot areas. This study showed not only the meteorological characteristics of some lightning producing systems but also the elevated regional lightning activity, which should be an important concern to the electric power distribution systems and other human activities in eastern Amazonia.
Acesso aberto (Open Access)
Influência do tipo de superfície na densidade de ocorrência de raios sobre áreas da Amazônia Oriental
(Universidade Federal do Pará, 2013-10-02) AARÃO JUNIOR, Raimundo Nonato Nascimento; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
The objective of this study was to analyze the relationship between the occurrence of lightning over different types of surfaces in selected areas situated in the eastern part of the Amazon Region during the period of July 2008 to November 2010. The studies were conducted in 8 areas, located in the State of Pará, Brazil. The studied areas feature a particular type of surface with homogeneous character. The lightning data were obtained from the database of the STARNET lightning detection network. Rainfall data were collected through 80 weather stations of the National Water Agency - ANA and the National Institute of Meteorology - INMET, while data classification of the types of surfaces were obtained from the Brazilian Institute of Geography and Statistics - IBGE. The results showed that different types of surfaces have contribute a significantly in occurrence frequency of lightning; lightning vary depending on seasonality and over the months during the year, with higher averages of correlated events with the period of maximum rainfall; the occurrence of lightning varies in time function, where both the rainy season and in the dry season the occurrences of these events tend to happen during the period between 14:00 UTC (15:00 UTC to dry season) and 22:00 UTC with major peaks observed in the rainy season. Also observed a lack of uniformity in the incident of lightning and precipitation on and between the same selected areas. Therefore, this study provides qualitative evidence of the importance of the types of surfaces and their influence over the observed occurrence of lightning.
Acesso aberto (Open Access)
Lightning and precipitation produced by severe weather systems over Belém, Brazil
(2014-12) RIBEIRO, Wanda Maria do Nascimento; SOUZA, José Ricardo Santos de; LOPES, Marcio Nirlando Gomes; CÂMARA, Renata Kelen Cardoso; ROCHA, Edson José Paulino da; ALMEIDA, Arthur da Costa
CG Lightning flashes events monitored by a LDN of the Amazon Protection System, which included 12 LPATS IV VAISALA sensors distributed over eastern Amazonia, were analyzed during four severe rainstorm occurrences in Belem-PA-Brazil, in the 2006-2007 period. These selected case studies referred to rainfall events, which produced more than 25 mm/hour, or more than 40 mm/ 2 hours of precipitation rate totals, registered by a tipping bucket automatic high-resolution rain gauge, located at 1º 47' 53" S and 48º 30' 16" W. Centered at this location, a 30 ,10 and 5 km radius circles were drawn by means of a geographic information system, and the data from lightning occurrences within this larger area, were set apart for analysis. During these severe storms the CG lightning events, occurred almost randomly over the surrounding defined circle, previously covered by mesoscale convective systems, for all cases studied. This work also showed that the interaction between large-scale and mesoscale weather conditions have a major influence on the intensity of the storms studied cases. In addition to the enhancement of the lightning and precipitation rates, the electric activity within the larger circles can precede the rainfall at central point of the areas.
Acesso aberto (Open Access)
Planejamento de sistemas de proteção contra descargas atmosféricas para unidades habitacionais de baixa renda
(Universidade Federal do Pará, 2014-02-24) SANTOS, Diego Guimarães dos; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
This research have the purpose to realize a study about the lightning occurrence profile over the municipalities of Belém, Ananindeua and Marituba, in the period of 1991 to 2011 with the objective to establish the lightning occurrence profile in these municipalities, as well as identify what kind of factors need to be observed and/or identified with the finality to realize an appropriate planning of protection systems against lightning in low income housing builded by the acceleration program of development from the federal government, more precisely in Taboquinha housing, located on the district of Cruzeiro in Icoaraci. After the realization of the comparative analysis with lightning occurrence data proceeding from the lightning detection network STARNET, lightning occurrence data from LIS sensor installed on board of the TRMM satellite, as well as lightning data acquired by the Brazilian Association of Technical Standards NBR 5419, it was possible to conclude that the Taboquinha housing need an appropriate protection system against lightning due to sinister occurrence records involving direct incidence of atmospheric discharges, as well as your secondary effects. In the end of this research will be presented some discussion topics related with some conclusions about the lightning occurrence profile in the present region presented by the NBR 5419 standard, because this incoherent conclusion may harm the public patrimony, as well as the common citizen and their construction.
Acesso aberto (Open Access)
Previsão de raios através de índices termodinâmicos da atmosfera, em torno de Belém do Pará
(Universidade Federal do Pará, 2014-01-20) SILVA, Cássia Camila Silva da; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
The Amazon region often has most of its surface covered by cumulus type clouds which, to thrive, need a thermodynamic forcing (source of heat and humidity) and dynamic forcing (wind). The city of Belém-Pa is located in one of the rainiest regions of the Amazon, due to the strong convective activity in the region. One of the natural phenomena, besides precipitation, which causes destruction and losses to the population of the Amazon region is lightning, usually associated with the thunderstorms. The overall goal of this work is to create a statistical model based on the decision tree method, which consists of a computational intelligence technique, in order to find a relationship between thermodynamic indices of the atmosphere and the occurrence of lightning. We used data from radio soundings of the atmosphere made daily from Belém airport and published at an Internet site by the University of Wyoming. Additionally, lightning daily occurrences within a 100 km radius area around the sound launching site were drawn from the STARNET lightning monitoring network data base; which covers the entire Amazon. The results showed that the rules of the decision tree are significant because the critical values of thermodynamic indices of the model are similar to those described in the literature. The decision tree model establishes rules that can help in forecasting weather and lightning in the region ofsurrounding Belém. The study of atmospheric thermodynamic indices versus the occurrence of lightning showed a positive relationship where the evaluation of the model obtained a result of 94% correct values. This is considered good for building a statistical model representation for the occurrence and severity of electrical discharges from the atmosphere.
Acesso aberto (Open Access)
Relações entre raios e chuvas na Amazônia Oriental
(Universidade Federal do Pará, 2012-08-24) POMPEU, Marcela Machado; SOUZA, José Ricardo Santos de; http://lattes.cnpq.br/2797414407717271
The objective of this study was to analyze the relationship between electrical discharges of the atmosphere and the precipitation in selected areas of eastern Amazonia during the period of September 2008 to December 2010. These areas correspond to three target circles of similar latitudes and two river basins, all located in the eastern Amazon Region.The first type of studies were conducted within radii of 100 km,centered at rain gauges within the towns of Belém, Caxiuanã and Santarém. These areas were chosen because they are situated roughly the same latitudes but ,different distances from the Atlantic Ocean. The objective was to observe the seasonality of the precipitation systems which cause lightning and their penetration in the continent, to determine the different climatological characteristics of each area. Lightning data was obtained fron the STARNET siystem. The rainfall data were obtained from the database of the ANA, RPCH, INMET and through the LBA station in Caxiuanã. The large-scale weather systems accompanied by small scale systems, appear to act primarily in Belém and weaken as they propagate to the other areas of study.In Belém, it was a observed the highest occurrences of lightning compared to Caxiuanã and Santarem.The peaks of lightning occurrences Caxiuanã and Santarem, approximately two months .The effect of the north-south drif of the ITCZ and its coupling with other systems at local or meso scale was observed. Analysis was made of a case study in Belem and Santarem and it was show that in the ITCZ does not follow the same pattern for these theree areas. A second type of study consited in na aplication within the basins of the Tocantins and Xingu River through a pioneering study of the relationship between lightning and rainfall.It was an attempt to contribute to predict the periods of floods and droughts within these basins through electrical discharges data. The detailed study was conducted in the areas upstream of dams in the Tocantins area1 where the Tucuruí hydroelectric power plant was installed, and also within the area of the Xingu basin is being built where the Belo Monte dam rainfall data from-HIDROWEB ANA pluviometric station operated by CPRM in each study area, were and also obtained in these basins . Using moving average filtes applied to lightning and rainfall,it was observed that the best relationship between, these variables occurred within the basin of the Tocantins, probably because it has more rain fall stations than the Xingu.basin.Considering the fact that the data corresponding to only two years of observations does not provide enough statistical weight to establish permanent quantitative relationships between lighting occurrences and rainfall, the derived equations may be considered as preliminary results. Nevertheless it was well established that this methodological approach may be applied to subsidize estimates of precipitation over selected areas, as well as, contribute with information to hydrological models for river basins, especially where pluviometric data are data are scarce and need an alternative source of information, in eastern Amazonia.
Acesso aberto (Open Access)
Um simulador para avaliação da influência das características locais das descargas atmosféricas nuvem-solo em sistemas de detecção indireta
(Universidade Federal do Pará, 2017-01-10) SHINKAI, Ricardo de Andrade; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
The monitoring of the phenomenon of atmospheric discharges has been fundamental to prevent incidents in the infrastructure of companies that operate in large areas, such as energy, telecommunications and information technology. In addition, it provides data for the planning of lightning protection systems, thus avoiding further damage to life on Earth, and more recently providing information for weather warning systems such as short-term storm forecasting. Therefore, it is no longer a matter of choice, but rather the need to install and maintain systems that supervise these events on a local, regional and even national scale. Among the possible types, the Lightning Location Systems are the ones that provide more accurate information in the mentioned scales, because they work with the perception of the electromagnetic impulse generated by the lightning. This signal has the property of propagating at medium and long distances in certain frequency bands, maintaining good the information quality of the phenomenon that originated it. However, the phenomenological characteristic of the lightning is intrinsic to the monitored area, making fundamental the understanding of these specificities to better benefit the mentioned systems. This work presents a computational tool to simulate the influence of local characteristics on the propagation of electromagnetic waves caused by cloud-to-ground lightning. The methodology was used to simulate the propagation of these waves through the MATLAB® program, using as model of return current in the discharge channel the model of engineering type the Transmission Line (TL) to represent the electric phenomenon generated by thelightning.
Acesso aberto (Open Access)
Utilização de satélite geoestacionário para avaliar a incidência de raios em linhas de transmissão do sistema interligado nacional brasileiro
(Universidade Federal do Pará, 2024-07-24) MATOS, Wendler Luis Nogueira; LEAL, Adônis Ferreira Raiol; http://lattes.cnpq.br/4099411616990036; https://orcid.org/0000-0003-0606-2950
Lightning is responsible for the death of people and animals, in addition to damage to the electrical system, within the scope of distribution and transmission networks. One of the main parameters for evaluating the occurrence of lightning is the lightning density in a given region of interest. The GLM sensor, on board the GOES-16 geostationary satellite, allows continuous monitoring of the Americas. Through data processing, it is possible to plot the lightning density for any region within the field of view. The use of this data allows monitoring the occurrence of lightning, helping to identify regions at greater risk of damage associated with lightning. In the case of a large country like Brazil, that has many transmission lines with hundreds of kilometers, forming the National Interconnected System (SIN), it is essential to have updated and regionalized data. Data from the National Electric System Operator (ONS) were processed, and important information about the SIN lines was presented, such as the number of lines per voltage level and their lengths in kilometers, number of line failures per year, per month and by voltage level, as well as the percentage of each type of failure, noting that the main cause of failures is due to lightning, with 25%, being one of the points that supported the importance of this work. The objective of the dissertation is to provide updated lightning density data in the period 2019-2023 for all transmission lines belonging to Brazil's base power transmission network, at the following voltage levels: 230, 345, 440, 500, 525, 600, 765 and 800 kV. Maps were generated for each voltage level, and also a general map for the entire SIN and the entire Brazilian territory. The monthly amount of lightning was compared with the monthly number of faults, observing that the most critical periods of the year are the first and last quarter. Considering all transmission lines, the average lightning density was 11.74 lightning/km2/year, and for Brazil it was 13.17 lightning/km2/year, with a maximum value of 57.62 lightning/km2/ year. Furthermore, the average number of lightning, during the 5 years, was 46 million for the SIN lines and 98 million for Brazil. Finally, a very strong correlation was observed, with a coefficient of 0.91, between the monthly number of lightning and the monthly number of faults caused by lightning, during the observation period.