Navegando por Autor "OLIVEIRA, Juarez Ventura de"

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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)
A oscilação Madden - Julian na Amazônia Oriental: variáveis superfíciais
(Universidade Federal do Pará, 2012-06-29) OLIVEIRA, Juarez Ventura de; VITORINO, Maria Isabel; http://lattes.cnpq.br/4813399912998401; SÁ, Leonardo Deane de Abreu; http://lattes.cnpq.br/0107976161469463
The aim of this work is to investigate the influence of the Madden - Julian Oscillation (MJO) on turbulent elements of the Atmospheric Boundary Layer (ABL). The MJO was identify on a time series of 30 years of outgoing long-wave radiation (OLR) and zonal component of the wind (u). The turbulent parameters were studied through the covariance and the correlation coefficient of a fast response data set collected on Caxiuanã’s (Pa) micrometeorological tower. The difference between each phase of the MJO was statistically analyzed with the t test of Student. The OLR and u data set results shows that the MJO occurrence is linked to El Niño / Southern Oscillation (ENSO) happening. The El Niño phase of an ENSO tends to diminish the chances of MJO case to develops, the opposite situation is identify during an La Niña episode, when the MJO is favored by the dynamics of the ongoing ENSO mechanism. If a MJO occurs during an El Niño, it can change the temperature, wind velocity and the precipitation expected for an El Niño year. The MJO’s phase analysis, for Belém, reveled a significant difference on precipitation and maximum temperature between the active and inactive phase, but for minimum temperature and wind module, this difference is little significant. The turbulent kinematic fluxes, analyzed by scale on each phase of the MJO, during three different periods of the day, were more distinct during the daytime period, with high confidence levels, mostly on w’T’ and w’q’ fluxes. The day – night transition and the night period were less different, with only a few scales showing more than or exactly 95% of confidence during the transition, and with none scales reaching the 95% mark during the night. Those results indicate that the diurnal convection is the responsible mechanism for this differences, and as the MJO is like a big convective cell, the local convection during its active phase is amplified, explaining the differences found during the daytime period.