Navegando por Autor "SILVA, Renato Ramos da"

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Acesso aberto (Open Access)
Climate estimates for Eastern Amazon with OLAM model
(2014-12) SILVA, Renato Ramos da; VITORINO, Maria Isabel; KUHN, Paulo Afonso Fischer; ANANIAS, Daniela dos Santos
The OLAM model has as its characteristics the advantage to represent simultaneously the regional and global meteorological phenomena using a refining grid scheme. During REMAM project OLAM was applied for a few case studies with the goal to evaluate its performance to estimate the regional climate for the eastern Amazon during periods of El Niño and La Niña. Case studies were performed for the rainy periods of the years 2010 and 2011 that were driven by distinct oceanic conditions. Initially, the model results were compared with local observations. The results demonstrated that OLAM was able to represent well the major precipitating regions, the diurnal temperature cycle evolution, and the wind dynamics. After that, analysis of the results demonstrated that if we provide good initial conditions and a good representation of the sea surface temperature evolution, OLAM is able to forecast with two or three months in advance if a rainy season would be wet or dry.
Acesso aberto (Open Access)
Insights of meso and micro-scale processes for the Caxiuanã forest region from high resolution simulation
(2012-07) MESQUITA, Renata Leitão da Conceição; SILVA, Renato Ramos da
Meteorological data and high resolution numerical simulations were used to estimate spatial fields in eastern Amazonia where is located the Forest and the Bay of Caxiuanã. The study were performed for the period of November 2006, when occurred the field experiment COBRA-PARA. Analysis of the MODIS sensor from the Terra Satellite images show the occurrence of various phenomena such as local cloud streets, precipitating convective systems and an important influence of the interfaces between the forest and water surfaces. Numerical simulations for November 7, 2006 showed that the model represented well the major meteorological processes. 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 canopy temperature to the west of the bay and convective rainfall. Simulations with high resolution (LES) produced spatial patterns of temperature and humidity aligned with the winds during the daytime, and at nighttime the patterns are influenced mainly by the presence of the bay. Correlations between the mid-level winds and the latent heat fluxes showed that there is a change from negative correlations for the early hours to positive correlations for the afternoon and early evening.
Acesso aberto (Open Access)
Modelo OLAM (ocean-land-atmosphere-model): descrição, aplicações, e perspectivas
(2009-06) SILVA, Renato Ramos da; DIAS, Pedro Leite Silva; MOREIRA, Demerval Soares; SOUZA, Everaldo Barreiros de
The OLAM model was developed to extend the capability to represent the global and regional scale phenomena simultaneously. The model presents innovations regarding to the dynamic processes, grid configuration, memory structure, and numerical technique solutions for the prognostics equations. The Navier-Stokes equations are solved using the finite volume technique that conserves mass, momentum, and energy. In this study the OLAM model is described, and results are presented for its application on the climate mode to simulate the monthly prediction of precipitation for South America and numerical weather prediction. The results show that the model is able to represent reasonable the large scale meteorological processes. In general, its performance improves when grids of greater resolution is adopted, for which significant improvements are observed for the monthly precipitation simulation estimates as for the numerical weather prediction.
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).
Acesso aberto (Open Access)
Weather forecasting for Eastern Amazon with OLAM model
(2014-12) SILVA, Renato Ramos da; GANDU, Adilson Wagner; COHEN, Júlia Clarinda Paiva; KUHN, Paulo Afonso Fischer; MOTA, Maria Aurora Santos da
The OLAM model has as its characteristics the advantage to represent simultaneously the global and regional meteorological phenomena using the application of a grid refinement scheme. During the REMAM project the model was applied for a few case studies to evaluate its performance on numerical weather prediction for the eastern Amazon region. Case studies were performed for the twelve months of the year of 2009. The model results for those numerical experiments were compared with the observed data for the region of study. Precipitation data analysis showed that OLAM is able to represent the average mean accumulated precipitation and the seasonal features of the events occurrence, but can't predict the local total amount of precipitation. However, individual evaluation for a few cases had shown that OLAM was able to represent the dynamics and forecast a few days in advance the development of coastal meteorological systems such as the squall lines that are one of the most important precipitating systems of the Amazon.