Navegando por Autor "CUNHA, Alan Cavalcanti da"

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Acesso aberto (Open Access)
Evento extremo de chuva-vazão na bacia hidrográfica do rio Araguari, Amapá, Brasil
(Universidade Federal do Pará, 2014-12) CUNHA, Alan Cavalcanti da; VILHENA, Jefferson Erasmo De Souza; SANTOS, Eldo Silva Dos; SARAIVA, Jaci Maria Bilhalva; KUHN, Paulo Afonso Fischer; BRITO, Daímio Chaves; SOUZA, Everaldo Barreiros de; ROCHA, Edson José Paulino da; CUNHA, Helenilza Ferreira Albuquerque; BRITO, Alaan Ubaiara; BRASIL JUNIOR, Antonio Cesar Pinho; PACA, Victor Hugo da Motta; SANTOS, Paula Verônica Campos Jorge
The objective of this investigation was to analyse the extreme river flows which have occurred between 9 and 14 April 2011 in the Rio Araguari-AP. The methodology consisted of three main steps: 1) re-analysis of precipitation estimated by the BRAMS (Brazilian Development in Regional Atmospheric Model System) model using the synoptic of the same period as support, 2) analysis of streamflow in sections of hydrological monitoring in Porto Platon, Capivari and Serra do Navio (ADCP-Accustic Profiller Doppler Current); 3) statistic analysis of the time series of maximum river flows in Porto Platon using Gumbel distribution. It was observed that the BRAMS system partially captured the standard precipitation when compared with the synoptic analysis and literature data, but the extreme hydrological responses representation still needs an optimization. In Porto Platon a flow record of 4036 m3 /s was recorded, whose behavior was analyzed from the perspective of the available monitoring mechanisms in the State. It was concluded that such extreme events are poorly detectable and offer considerable risks to users of the basin. The stream flow prediction based on available hydrological series was 100 years recurrence, but the analysis have revealed that this period would be 360 years, indicating significant deficiency of the prediction system of extreme events in the State.
Acesso aberto (Open Access)
Hydroelectric power plant in the amazon and socioeconomic impacts on fishermen in Ferreira Gomes county – Amapá state1
(Universidade Federal do Pará, 2017-07-30) CUNHA, Alan Cavalcanti da; CUNHA, Helenilza Ferreira Albuquerque; SANTOS, Erick Silva dos
Socioeconomic impacts of the construction of the Ferreira Gomes Hydroelectric Power Plant (UHEFG) were analyzed in communities of fishermen affected before and after the filling of the reservoir. The study occurred between 2014 and 2015, in the municipality of Ferreira Gomes-AP. Data were collected using forms (Nsample=48) and a comparative analysis was performed to evaluate their significance (Mann-Whitney, p<0.05). The results showed that the Environmental Impact Assessment (EIA) did not adequately predict impacts in the fisheries sector. The comparative tests confirmed a) six variables with significant variation (p<0.05): monthly income, number of trips to fish, fishing difficulties, environmental conditions of the Araguari River, socioeconomic and environmental impacts; and b) a variable at the limit of significance (p≈0,056): fish trade. We concluded that the reparatory measures did not reestablish the socioenvironmental conditions, generating conflicts not foreseen.
Acesso aberto (Open Access)
Modelagem climática regional durante dois anos de extremos de precipitação sobre o estado do Amapá: teste de sensibilidade aos esquemas convectivos
(2011-12) NEVES, Daniel Gonçalves das; CUNHA, Alan Cavalcanti da; SOUZA, Everaldo Barreiros de; BARRETO, Naurinete Jesus da Costa
This study shows an assessment of the seasonal forecast model RegCM3 in two extreme events of precipitation for the years 2006 and 2007. For the analysis a 1° x 1º km horizontal resolution was used and validated with 30 x 15 points of latitude x longitude for the region of the State of Amapa. The presented results are for the comparison between simulated and observed seasonal precipitation in the quarter (MAM). In general, the results showed that using the scale reduction technique to predict the seasonal rainfall, a good performance in simulating the variability of rainfall on a regional scale is obtained. However, errors in the precipitation amount and on some maximum position were observed when compared with the observed data. The wet bias was prevalent in the humid coastal region and the dry bias in the south-southeast, west and center with a strong persistence in the Southeast. Regions with precipitation values close to the observed ones were not very evident.
Acesso aberto (Open Access)
Precipitação sazonal sobre a Amazônia oriental no período chuvoso: observações e simulações regionais com o RegCM3
(2009-06) SOUZA, Everaldo Barreiros de; LOPES, Marcio Nirlando Gomes; ROCHA, Edson José Paulino da; SOUZA, José Ricardo Santos de; CUNHA, Alan Cavalcanti da; SILVA, Renato Ramos da; FERREIRA, Douglas Batista da Silva; SANTOS, Daniel Meninéa; CARMO, Alexandre Melo Casseb do; SOUSA, José Raimundo Abreu de; GUIMARÃES, Paulo Lima; MOTA, Maria Aurora Santos da; MAKINO, Midori; SENNA, Renato Cruz; SOUSA, Adriano Marlisom Leão de; MOTA, Galdino Viana; KUHN, Paulo Afonso Fischer; SOUZA, Paulo Fernando de Souza; VITORINO, Maria Isabel
This paper presents a contribution on the climate modelling studies with emphasis on seasonal rainfall variability in eastern Amazonia, during the austral summer and autumn seasons (DJF and MAM). Based on RegCM3 regional climate simulations for a 26 years period (1982/83 to 2007/08) using high resolution domain scale (30 km) and two different convection schemes (Grell and MIT), it was investigated the model performance to simulate the regional pluviometric distribution in eastern Amazon, with reference to a new observational data base containing regional aspects extracted from a dense rain gauge station network. The quantitative analysis showed that RegCM3 presents systematic errors, especially those related to the dry bias in the Amapá and north/northeast of Pará using both schemes Grell and MIT, which indicate that the model does not reproduce ITCZ characteristics over equatorial Atlantic. The simulations using MIT also indicated wet bias in the southwest/south/southeast of Pará and north of Tocantins. Moreover, through composites technique, it was also investigated RegCM3 response to reproduce the anomalous spatial rainfall patterns in association with ENSO episodes and interhemispheric SSTa gradient phases across the intertropical Atlantic. The results showed that the model represented realistically well the spatial pattern related to the rainfall anomalies above (below) than normal in most of eastern Amazonia, during the known favourable scenarios, i.e., La Niña and south Atlantic SSTa gradient (unfavourable, i.e., El Niño and north Atlantic SSTa gradient).