Navegando por Assunto "Meteorologia"

Agora exibindo 1 - 13 de 13

Acesso aberto (Open Access)
Acidentes com transportes hidroviários e os extremos meteorológicos no nordeste da Amazônia
(Universidade Federal do Pará, 2015-03-30) SANTOS, Suanne Honorina Martins dos; VITORINO, Maria Isabel; http://lattes.cnpq.br/4813399912998401
This study analyzed the accidents with waterway transport passengers and cargo in the period 2008 to 2013, as a result of extreme weather occurring in the northeast Amazon, often with serious consequences the structure of vessels and especially the loss of human life. Based on data from the Flagship of the Eastern Amazon Ports, referring to the investigation of accidents facts of navigation, can be characterized in that period these accidents occur more and the distribution of these accidents in time and space, through sub-areas called 1, 2 and 3, where they are ranked the most common accidents in Subarea 1 type shipwreck where the basin of Marajó is located with features of larger rivers, in Subarea 2 and 3 of collision type where the morphological characteristics of rivers are narrower as well, in addition to these results was obtained in relation to rainfall in the rainy season (December to May) as the most responsible for accidents occurring during this period that suffers strong influence of precipitation systems as the Intertropical Convergence Zone, Mesoscale Convective Systems, instability lines and vortex of Advanced Levels and the less rainy season (June to December) the wind is regarded as the main variable that causes accidents in the waterway mode, especially during the intensification of the northeast trade winds, which are a free atmosphere of instability, accidents tend to occur more frequently in the time from 12 to 24 hours. Thus, with the precipitation climatology with the National Institute of Meteorology data, one can show through the climatology of the precipitation field of study, decreased quantity of deeper into sub-areas of the continent. The wind in the less rainy period acts with greater intensity in Subarea 1, the highest number of victims focuses on children and adults, mostly with men. It also presented an approach based on the socioeconomic aspects inherent risks of naval vessels with steel hulls and wood, the latter being the reality of the Amazon, which ultimately victims the more people and have more easily collapse structure, thus being potential threat to safety of navigation of cargo and passengers taking into account socioeconomic characteristics, although the vessels with the highest number of accidents has been pushers ferries built in naval steel. In this sense, the primary aid weather forecasting may decrease the favorable conditions for the occurrence of accidents with waterways vessels, because the lack of atmospheric conditions by those who pilot vessels is notoriously poor, because this lack of knowledge the chances of accidents are high, influencing the socioeconomic aspects of passengers and owners of vessels navigating the rivers belonging to the Marajó Bay, Tocantins, Pará and Amazonas river, which were the waterways studied in this dissertation.
Acesso aberto (Open Access)
Avaliação de características dos regimes de umidade na flona de Caxiuanã-PA durante o experimento COBRA-PARÁ
(2010-03) TANAKA, Ludmila Monteiro da Silva; SÁ, Leonardo Deane de Abreu; MOTA, Maria Aurora Santos da
We investigate the validity of a method of humidity regimes classification, based on different "states" characterization of the Tropical Atmospheric Boundary Layer (TABL), above a forest area, according to the methodology proposed by Mahrt (1991). To perform this investigation we used radiosonde information and micrometeorological tower data collected during the drier season of the region, during the experiment "COBRA-PARÁ" (carried out from 30/10 to 15/11, 2006). The analysis of moisture regimes is based on the "phase space" data representation, where the Bowen ratio (β) is plotted against the -h/L parameter (where h is the height of the turbulent mixing layer and L is the Obukhov length scale). According to the location of the data value in this "phase space" it was possible to identify the following classes: Class I - dry air and unstable conditions, Class II - dry wind, Class III - wet wind, Class IV - wet air and unstable conditions, Class V - occurrence of water condensation on the surface, Class VI - stable conditions predominance and Class VII - dew formation generated by nocturnal radiative losses with surface cooling. Among the mentioned classes, the III, IV and VI were the most frequently observed at Caxiuanã.
Acesso aberto (Open Access)
Caracterização de regimes de umidade em regiões tropicais: comparação entre floresta e savana
(Universidade Federal do Pará, 2008-08-11) SILVA, Ludmila Monteiro da; SÁ, Leonardo Deane de Abreu; http://lattes.cnpq.br/0107976161469463; MOTA, Maria Aurora Santos da; http://lattes.cnpq.br/5817549281617240
This study aims to investigate a method to classify humidity regimes based on different "states" characterization of the Tropical Atmospheric Boundary Layer (TABL), both above a forest area and above a savanna area, according with the methodology proposed by Mahrt (1991). Starting this classification, an improvement is performed while incorporates both the analysis of the thermodynamic stability of TABL for a forest area and the variation in Convection Available Potential Energy (CAPE). In these analyses, radiosonde data and data from micrometeorological towers obtained during field experiments have been used, collected during the less rainy period in each area. For the forest area (Caxiuanã) data from the COBRAPARÁ experiment were used (spanning the period from 06 to 13/11 of 2006), while for the savanna area (Daly Waters) data from the “KOORIN” experiment were used (spanning the period from 15/07 to 13/08 of 1974, in Australia). The comparison of humidity regimes of each area suggests that, should the Amazon rainforest be replaced with savanna, this would result in a drier atmosphere, with most of the energy used for the heating of that atmosphere, reduced evapotranspiration, decreased precipitation and the inexistence of CAPE. On the other hand, the analysis of the stability of the atmosphere in Caxiuanã showed that, contrary to observations in the Western Amazon, during the COBRA-PARÁ Experiment, the largest values of CAPE occurred at 18:00 local time due to the humidity convergence that occurs in the bay of Caxiuanã through the land-breeze circulation, indicating that in that area the maximum values of CAPE were associated predominantly with the humidity fields and not with temperature. Under such a “disturbed” TABL conditions, the phase space proposed by Mahrt (1991) doesn’t characterize well moisture regimes associated with great CAPE values.
Acesso aberto (Open Access)
Complexo Convectivo de Mesoescala observado em 27/11/2002 no nordeste da Argentina
(2008-12) CAMPOS, Claudia Rejane Jacondino; LIMA, Edna Cristina Sodré; PINTO, Luciana Barros
In this work were analyzed the synoptic situations associated to a Mesoscale Convective Complex (CCM), observed on 11/27/2002 in the northeast of Argentina. Infrared imagery from GOES-8 and simulations from BRAMS regional model were used. The model simulation, with three hours issues, allowed detailing the behavior of the meteorological variables in large scale that affect the MCC life cycle, being able to reproduce the suitable conditions to its beginning, development and dissipation. The results showed that the MCC studied presented similar characteristics to those observed by several authors.
Acesso aberto (Open Access)
Episode of Low Level Jets in the north and northeast coast of state of Para: a case study of 2002 april 21st to 22nd
(2008-09) SOUSA, Adriano Marlisom Leão de; CAMPOS, Claudia Rejane Jacondino; ROCHA, Edson José Paulino da
In this study the characteristics of the vertical structure of an episode of Low Level Jets (LLJ) occurring in the coast of Para is described. Radiosonde data of Ajuruteua city in Bragança collected during the DESMATA Experiment (Impact of the Deforestation the Atlantic Coast of the Amazonian), taking place in 2002, from April 08th to 22th, are used. Among the detected cases during the rainy period, one specific case with 12 hours duration, average velocity of 15m/s and directed from NE to E in the point of maximum velocity was selected. The observational results have indicated that this LLJ located in the coast of Para was due to the combined action of two factors: (1) inertial oscillation and (2) superficial baroclinicity. These two combined factors sustained this LLJ with velocities between 10 and 13m/s during the day and between 14 and 16m/s during the night, at an average altitude of 800m above surface.
Acesso aberto (Open Access)
Estudo comparativo da distribuição espaço-temporal da precipitação na Amazônia Oriental
(Universidade Federal do Pará, 2008) GOMES, Nilzele de Vilhena; MOTA, Galdino Viana; http://lattes.cnpq.br/8821024246942574
This work used precipitation data during January 2000 to September 2007 from the gauge on the micrometeorological tower located in the Ferreira Pena Scientific Station in the Caxiuanã forest. This data was compared with the 3B42 algorithm, an estimate based on microwave to ajust infrared measurements. Additionally, the comparisons were extended do the Eastern Amazonia using five algorithms: The Geostationary Environmental Satellite Precipitation Index (GPI); the 3B42; 3A12 and 3A25 that are based on the sensors of microwave and radar from the Tropical Rainfall Measuring Mission (TRMM) satellite; and the Global Precipitation Climatology Center (GPCC), from January 1998 to December 2007.The comparison between the 3B42 estimates with the gauge showed that the 3B42 algorithm overestimates the precipitation from the gauge for all period. The rainy trimonthly periods were in March-April-May (MAM) and December-January-February (DJF) and the less rainy periods were September-October-November (SON) and June-July-August (JJA), This seasonality of precipitation is caused by the different meteorological systems over the region, especially the Intertropical Convergence Zone (ITCZ) which modulates the rainy season over the region. The seasonal analyses showed that the 3B42 algorithm overestimates (underestimates) the rainfall compared with the gauge in MAM and JJA (DJF and SON); and DJF is the quarter what the estimates of precipitation is closer regarding the gauge measure in micrometeorology tower of Caxiuanã. In the monthly averages, the 3B42 algorithm underestimates the rainfall from October to January and overestimates from Mach to August compared to the gauge. The 3B42 algorithm overestimated (underestimated) the nocturnal (the morning and the afternoon) precipitation compared to the gauge in the six grids around Caxiuanã Reservation. However, both data showed the maximum period of precipitation of the diurnal cycle around 18:00 local time (LT). Also, the analysis of diurnal cycle seasonal average indicate what in DJF to 0900 LT, 1500 LT and 1800 LT have a precipitation estimated for 3B42 algorithm closer to gauge measured punctually in Caxiuanã.. The months of November to February have a major maximum of precipitation in the afternoon in both datasets. In the period from may to July the maximum of precipitation becomes nocturnal and in the early morning, changing the diurnal cycle compared to the other months. The comparisons between the five algorithms over the Eastern Amazonia showed different behaviors among the estimators. The GPI algorithm underestimated the precipitation compared to the other algorithms in the Amapá state and French Guyana; and overestimated in central area of Amazonia. Both estimators from TRMM satellite the 3A12 and 3A25 algorithms, presented less precipitation than the other algorithms. The 3B42 algorithm presented similar pattern of precipitation as that showed by Figueroa e Nobre (1990). However, the GPCC estimator showed less details in the spatial distribution of rainfall in the Northwest of Pará state. The differences between the algorithms here considered might be related to the characteristics of each algorithm and/or the methodology used. The comparison between a locally data from the gauge with the averaged data from satellites might be the explanation for the discrepancies in the seasons or in the diurnal cycle. However, the differences could be due to the differences of the nature of precipitation among the subregions; as systems modulating the diurnal cycle of rainfall over the Eastern Amazonia.
Acesso aberto (Open Access)
Estudo observacional sobre os eventos de seca meteorológica e hidrológica na região de Marabá-PA no sudeste da Amazônia Oriental
(Universidade Federal do Pará, 2011) CHAVES, Patrícia Malcher; SOUZA, Everaldo Barreiros de; http://lattes.cnpq.br/6257794694839685
The objective of the present work is to investigate observational aspects of the meteorological and hydrological drought in the region of Marabá located in the southeast of Pará in eastern Amazon. We used precipitation and river stream monthly data for the 1971 to 2010 period. The meteorological drought events were selected from categories of the negative values based on methodology of the precipitation anomaly index-IAC. The hydrological drought events were selected from fluviometric data below normal based on standardized anomaly index. For the meteorological drought conditions, the events are concentrated mostly in the categories of Weak drought (FRA) and Moderate (MOD), with higher frequency of FRA events in February (38%), June (37%) and December (34%), while the MOD events are more frequent in August (39%), September (42%) and October (32%). For the hydrological drought events of the Tocantins River, the results show that the monthly occurrence of events is random and can be observed throughout the year, so that the duration of the events present no regularity over the period studied. The dynamic structure associated with meteorological and hydrological drought are related to a large-scale pattern of El Niño in the equatorial Pacific and warmer conditions in the tropical north Atlantic, whose large-scale ocean-atmospheric conditions present intensification in both the atmospheric descending branch of the zonal Walker cell and meridional Hadley cell, which induce significant inhibition of tropical convective activity, thus explaining the occurrence of drought events in the region. Furthermore, it was analyzed the relationship between the drought events and vegetation fires (burning) points in the Marabá region during years 2000 to 2009, and the correlation of around 43% confirms the synergy between drought and fire, ie, the forest becomes more flammable under conditions of hydric deficit.
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)
Fungos poróides (Agaricomycetes) na Floresta Nacional de Caxiuanã: fenologia e relação com o substrato, topografia e fatores micrometeorológicos
(Universidade Federal do Pará, 2011-03-30) MEDEIROS, Priscila Sanjuan de; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
This study was conducted in one of the sites of Amazon Biodiversity Program (PPBio) located in the Caxiuanã National Forest (PA) and aimed to present the poroid fungi with emphasis on new record, analyze the relationship of these fungi with the woody substrate and to examine the association between micrometeorological variables (air temperature, relative humidity and rainfall) for one year, in relation to environmental variables, produced by topography, with richness, density, and phenology of these fungi. Were identified 76 species of poroid fungi, distributed in 27 genera and 5 families. The species Cerrena sclerodepsis, Phellinus dependens and Trametes pavonia represent the first records for the Pará state. Microporellus iguazuensis is mentioned for the first time in Brazil and presents the proposal of a new species to science, called Microporellus hirsuta. Most of the species was considered rare and showed preference for substrates in the early decomposition stages. The number of occurrences of basidiomata and fungi species was higher on the stem of the families plants Caesalpinaceae, Sapotaceae, Annonaceae, Mimosaceae and Lecythidaceae, respectively, and at substrate with a smaller diameter. It was expected that differences in microclimate generated by different altitudes, in a short topographic gradient, were sufficient to generate differences in the poroid fungal community. However, although it was found a greater number of species in a region called the intermediate, this difference was not significant. The largest number of individuals was found in the first rains and the richness is positively correlated with rainfall. The activity index of basidioma production of the abundant species was higher during the first rains after the dry period. This study represents an advance in understanding the relationships of the fungi with the environment in which they grow, mainly in tropical regions, but many studies still need to be developed to clarify these relationships.
Acesso aberto (Open Access)
Influência de elementos meteorológicos na percepção de risco e nas condições de insegurança da população local: incêndios residenciais em área de aglomerado subnormal no bairro do Jurunas, cidade de Belém – Pará.
(Universidade Federal do Pará, 2018-05-29) VILACORTA, Arthur Arteaga Durans; LIMA, Aline Maria Meiguins de; http://lattes.cnpq.br/6572852379381594; SILVA JÚNIOR, João de Athaydes; http://lattes.cnpq.br/2150400764733967
Brazil has witnessed a population growth that, together with the disorderly urban density, culminated in the increase of subnormal clusters in the last decades. Such locations present considerable vulnerability to dangerous events, especially fires. The present study analyzed statistical data on fires in residential buildings and green areas served by the Pará Military Fire Brigade in the city of Belém, between 2008 and 2016, relating them to meteorological elements, establishing a causal link between such aspects. In addition, questionnaires were applied to a sample of residents living in the precarious settlement area entitled Baixadas da Estrada Nova Jurunas in order to analyze the influence of climatological factors on the behavior of the population and to assess their level of perception of fire risk. As a final research product, two fire risk maps were proposed in residence for the subnormal cluster, one for the rainy season and one for the less rainy season. These maps were conceived through the establishment of a risk classification methodology (Arteaga-Athaydes index), based on georeferenced data of the location of the structural fires already occurring in the area, number of households, number of inhabitants, reliability conditions of the network facilities of electricity distribution of the dwellings and influence of the climate. It was concluded that the majority of fires in green areas and housing units in the city of Belém occurred in the least rainy season (June to November), due to the proven influence of meteorological conditions on the behavior of the sample studied, making them adopt inadequate arrangements that go against fire safety. As for the level of risk perception of the population sample that lives in the subnormal cluster studied, this condition is worrisome, since half of those interviewed do not believe that a loss could occur in their house and the vast majority never received any training or orientation to avoid accidents and does not even know the emergency number to fire the Military Fire Department in case of fire.
Acesso aberto (Open Access)
Modelagem dos processos meteorológicos de meso e micro-escala na região da floresta de Caxiuanã-Pa
(Universidade Federal do Pará, 2010) CONCEIÇÃO, Renata Leitão da; SILVA, Renato Ramos da; http://lattes.cnpq.br/9733821952821123
Meteorological data and high resolution numerical simulations were used to produce spatial fields in the eastern Amazonia where lies the Forest and the Bay of Caxiuanã near the site of the Project PPBIO, during the COBRA-PARA field experiment. Analysis of the MODIS sensor satellite images show the occurrence of various phenomena such as local cloud streets, formation of convection and an important influence of the interfaces between the forest and water surfaces. The numerical simulations show that the model represented well some meteorological variables for 07 November, 2006, but failed to properly represent the evolution of the atmosphere for to the next day. The model simulates well the temperature of the forest canopy, which is an important variable of interest to other research branches of the PPBIO project. The results show that the Caxiuanã Bay causes significant impact on adjacent meteorological fields mainly through advection by the northeast winds that induce to colder temperatures of the canopy to the west of the bay. Simulations with high resolution with capability of simulating the Large Eddies (LES) show spatial patterns of temperature and humidity aligned with the winds during the daytime, and at nighttime changes are caused mainly by the presence of the bay. The simulation produced a convective system with high resolution showing significant influence of downward gust fronts in the surface fluxes. The sensitivity experiments showed that stronger low level jets caused greater latent heat flux in the early hours of the day. Correlations between the jets and the latent heat fluxes showed that there is a change from negative correlations for the early hours into positive correlations for the afternoon and early evening. This shows that the downdrafts associated gust fronts have important influences on the spatial distribution of surface fluxes. Moreover the replacement of surface water by forest showed an increase in precipitation suggesting that the forest plays a fundamental role in local recycling of water.
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 sazonal da condutância estomática em um ecossistema de manguezal amazônico e suas relações com variáveis meteorológicas
(2011-06) RODRIGUES, Hernani José Brazão; COSTA, Rafael Ferreira da; RIBEIRO, João Batista Miranda; SOUZA FILHO, José Danilo da Costa; RUIVO, Maria de Lourdes Pinheiro; SILVA JUNIOR, João de Athaydes
This work investigated the variations of stomatal conductance (gs) in the rainy and dry seasons and its dependence relations with meteorological variables measured in an Amazonian mangrove ecosystem. Data were originated from the ECOBIOMA project, part of the Large Scale Biosphere-Atmosphere Experiment in Amazon (LBA). Stomatal conductance followed the tendency of the radiation balance variation, reaching maximum values during the day and minimum values at night. The conductance showed greater fluctuations in the rainy season, with mean value of gs = 0.015 m s-1, however smaller in magnitude than in the dry season. During the dry season, the mean value was gs = 0.027 m s-1, with lower range, varying between 0.010 and 0.042 m s-1. The meteorological variables used for establishing the dependence relations with the daily variability of stomatal conductance were the following; specific moisture deficit (δq), vapor pressure deficit (PVD), net radiation (Rn) and wind velocity (Vv). The PVD showed the best correlation with gs, with R2 = 0.99 for both periods. In spite of the importance of Vv in the gaseous changes between the vegetation and the atmosphere, it presented the smallest influence in the mean variation of the gs, with R2 = 0,44 for the rainy and R2 =0,51 for the dry period.