Navegando por Assunto "Metereologia"

Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Classificação climatológica da energia potencial disponível para a convecção na cidade de Belém-PA
(Universidade Federal do Pará, 2014-12) SANTOS, Josiane Sarmento dos; MOTA, Maria Aurora Santos da; ROCHA, Edson José Paulino da
The climatological classification of the Convection Available Potential Energy (CAPE) was studied in order to verify both the possibility of convection to start and the organizational type, in Belém (Pará - PA, Brazil), associating it to extreme precipitation events (EEPRP). For the CAPE analysis, DTCEA's radiosonde data and precipitation measurements from the INMET's stations, in the period from 1987 to 2011, we used. It was observed that the local atmosphere presented favorable conditions for the development of deep convection, because the most frequent CAPE values were higher than 1000 J/Kg, representing 61% of all radiosonde measurements. According to some authors, a CAPE value of 1000J/Kg is the deep convection limit. The CAPE 2 and 3 classifications presented significant increasing tendencies along the years, whereas CAPE 1 showed a decrease. This is probably due to the air temperature increased at the city, impacting the CAPE value. A low correlation between CAPE and EEPRP, as well as between CAPE and Pacific Ocean Index and the Atlantic Interhemispheric Gradient. was also shown. Therefore CAPE is not sufficient condition for the formation of clouds and precipitation, since meso and large scale dynamical forcing are relevant contributors to the climate modulation on the city.
Acesso aberto (Open Access)
Radar-observed spatial and temporal rainfall variability near the Tapajós-Amazon confluence
(Universidade Federal do Pará, 2014-12) COHEN, Júlia Clarinda Paiva; FIZJARRALD, David Roy; D'OLIVEIRA, Flávio Augusto Farias; SARAIVA, Ivan; BARBOSA, Illelson Rafael da Silva; GANDU, Adilson Wagner; KUHN, Paulo Afonso Fischer
Standard Amazonian rainfall climatologies rely on stations preferentially located near river margins. River breeze circulations that tend to suppress afternoon rainfall near the river and enhance it inland are not typically considered when reporting results. Previous studies found surprising nocturnal rainfall maxima near the rivers in some locations. We examine spatial and temporal rainfall variability in the Santarém region of the Tapajós-Amazon confluence, seeking to describe the importance of breeze effects on afternoon precipitation and defining the areal extent of nocturnal rainfall maxima.We used three years of mean S band radar reflectivity from Santarém airport with a Z-R relationship appropriate for tropical convective conditions. These data were complemented by TRMM satellite rainfall estimates. Nocturnal rainfall was enhanced along the Amazon River, consistent with the hypothesis that these are associated with the passage of instability lines, perhaps enhanced by local channeling and by land breeze convergence. In the daytime, two rainfall bands appear in mean results, along the east bank of the Tapajós River and to the south of the Amazon River, respectively.
Acesso aberto (Open Access)
Simulação da dispersão de poluentes atmosféricos e avaliação da qualidade do ar na área de abrangência do Distrito Industrial de Barcarena-PA
(Universidade Federal do Pará, 2012-04-30) ARAÚJO, Ivan Roberto Santos; ROCHA, Edson José Paulino da; http://lattes.cnpq.br/2313369423727020
The atmospheric pollution is considered, nowadays, one of the biggest problems of the contemporaneous society, turning into a menace to its life quality, because generates negative impacts in the natural and anthropogenic environment. In the range of the forms to control atmospheric pollution originated by settled sources, come forth the emission dilution in the atmosphere due to dispersal effects, the adoption of control equipments before the casting of gases or the relocation of the source, cause it seems to be a suggested form during the environmental licensing process enterprises with potential air pollution. Currently computer models of dispersion of atmospheric pollutants are being largely used on the simulation of concentration of pollutants, objecting to help environmental agencies in the prognostic of air quality or to supply deficiencies of atmospheric emissions monitoring. The present research studies the air quality e evaluates the atmospheric pollutants dispersal over Vila do Conde and influence areas of the industrial district of Barcarena, state of Para, with the help of the AERMOD View model, considering the possibility of establishment of a relation between the levels of pollutants emissions in the source, with the concentration of them in the air and identify critical points of pollution as well. The Air Quality Index – IQA and the fragility of the population over the affected areas by the atmospheric pollutants were also measured in the research. The methodology used allowed to measure the mean concentration of atmospheric pollutants during a defined time of modeling and also information about the reaching of the pollutants plume were acquired. Information concerning the relation between the peak and the mean values of concentration in the receptive areas provoked by enterprises that have operational characteristics similar to the modeled are showed too. The results show that the influence of the meteorological parameters in the dispersion of pollutants are indispensable and determinants in the impact on the air quality prevision and also in the land use planning of areas that have atmospheric polluting activities.