Navegando por Assunto "Modelagem atmosférica"

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Acesso aberto (Open Access)
Clima urbano de Belém, Pará: percepção climática, climatologia e modelagem atmosférica.
(Universidade Federal do Pará, 2020-01-29) OLIVEIRA, Juarez Ventura de; PIMENTEL, Márcia Aparecida; http://lattes.cnpq.br/3994635795557609; https://orcid.org/0000-0001-9893-9777; COHEN, Júlia Clarinda Paiva; http://lattes.cnpq.br/0293299378753887; https://orcid.org/0000-0003-2048-8915
The objective of this study is to investigate the influence of urbanization on Belém’s climate and how part of its population perceives climate change. Belém’s climate and the urban – atmospheric interaction were studied with meteorological station data and with simulations of three different soil cover scenarios (urbanization in 2017, 1986 and a scenario where all urbanization was replaced by forest) for the Belém’s Metropolitan Region (considered as the main urban areas of Belém, Ananindeua and Marituba) using the Weather Research and Forecasting (WRF) model. The perception analysis was made via a questionnaire applied in four places with different socio and environmental characteristics. These places were select from the Socio – Environmental Typology Map that was developed using 2010 Census data and satellite image. From the four sites, two of them represent well vegetated and verticalized region, with medium/high income population and low demographic density (typology Type III). The other two places represent areas with sparse vegetation, with low houses, low income population and high demographic density (Type I). The results showed that, regardless of the typology, the questionnaire participants noticed changes in the climate of Belém. According to them, due to the development of local urbanization, Belém is warmer and with higher precipitation variability. The Belém weather station corroborated this perception, but stations in nearby municipalities have also warmed in recent years, making it difficult to link this change with urbanization. However, there is a greater accumulation of precipitation in Belém, which was not observed on the other stations data, and from the WRF results it was observed that the current characteristics of the RMB (Belém Metropolitan Region) can intensify the development of local convective systems, causing stronger storms and consequently higher accumulation of precipitation due to increased vertical wind shear and available energy for convection. Although the participants have perceived these changes and have been impacted by them (different for each typology, but mainly health and financial issues), most of them do not know how to adapt their life to this new climate scenario or adapts inefficiently to it due to a lack of knowledge, time and/or financial resources. However, when it comes to Belém itself, the interviewees were able to suggest adaptation strategies that can have a significant impact on the local climate and even minimize the effects of urbanization on the atmosphere.
Acesso aberto (Open Access)
Modelagem de sistemas de detecção de descargas atmosféricas na Amazônia
(Universidade Federal do Pará, 2013-12-18) DENTEL, Laure Madeleine; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
Lightning is one of the greater risk factors for the Electricity Sector, especially in the Amazon, a region of the world identified with high lightning densities and peak currents. In this context, the Sferics Timing And Ranging NETwork (STARNET), which is presently the only free and continuous lightning detection system covering the whole Amazon Region was chosen to generate lightning parameter products required for the optimization of protection for transmission lines systems through continuous lightning monitoring. However, the intermittent activity observed in the Operating Diagrams of the various STARNET stations, impacted the system performances in special its detection efficiency. As a consequence, a model of standardization of lightning data was developed as a function of the network configuration (number and location of sensors in operation), with the final objective of editing reliable keraunic parameter as well as lightning densities maps. We found that there are Amazon regions which always have positive lightning density anomalies like the regions of Belém and Manaus, and the state of Tocantins. Next, the lightning incidence on transmission lines in amazon region was estimate from the peak current distribution of the Lightning Detection Network of the Amazon Protection System (SIPAM-LDN) and the standardized stroke density from the STARNET network. A comparative performance evaluation of STARNET with reference to the SIPAM-LDN also showed a strong dependence of the lightning detection efficiency of STARNET network on the peak current of lightning events.
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.