Douglas Batista da Silva Ferreira

Precipitação sazonal sobre a Amazônia oriental no período chuvoso: observações e simulações regionais com o RegCM3

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 Amapa and north/northeast of Para 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 Para 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 Nina and south Atlantic SSTa gradient (unfavourable, i.e., El Nino and north Atlantic SSTa gradient).

Climatologia da estrutura vertical da atmosfera em novembro para Belém-PA

Usando um conjunto de dados para um periodo de 26 anos (1982 a 2007), este trabalho apresentou um estudo diagnostico sobre a estrutura vertical da temperatura do ar, temperatura do ponto de orvalho e umidade relativa sobre a regiao de Belem-PA, durante o mes de novembro. As analises foram conduzidas para duas composicoes contrastantes no que se refere ao regime de precipitacao: a composicao dos anos chuvosos e a composicao dos anos secos, as quais foram estabelecidas objetivamente pelo metodo dos percentis. Os resultados apresentados permitiram concluir que a principal diferenca observada nos perfis de temperatura e umidade atmosferica, comparando-se os perfis dos anos chuvosos e secos, ocorre na camada atmosferica entre os medios e altos niveis da troposfera (entre os niveis padroes de 700 hPa e 400 hPa). Nesta camada, a diferenca entre as temperaturas do ar e do ponto de orvalho e significativamente maior e o contraste de umidade associado a conveccao tambem apresenta os maiores valores. Em geral, as composicoes demonstraram que os perfis de temperatura anomalamente mais quente (frio) e os de umidade anomalamente mais umido (seco) associam-se aos anos com registro de chuva acima (abaixo) do normal na regiao de Belem.

Spatial and Temporal Variability of Rainfall in Eastern Amazon during the Rainy Season

Empirical orthogonal functions (EOF) and composites analysis were employed on pentad data in order to investigate the tropical atmospheric-ocean patterns over the Atlantic Ocean and the spatial-temporal characteristics of the rainfall in eastern Amazon during the peak of the rainy season (February to April). The EOF results evidenced that the Intertropical Convergence Zone (ITCZ) is the main rainfall-producing system in eastern Amazon during the rainy season. Conditions associated with the southward SST gradient in the intertropical Atlantic formed the dynamic patterns that favored the position of the ITCZ to south of the equator, thus explaining the predominance of positive precipitation anomalies in eastern Amazon, especially in the state of Maranhao and northeastern Para during the February and April months.Empirical orthogonal functions (EOF) and composites analysis were employed on pentad data in order to investigate the tropical atmospheric-ocean patterns over the Atlantic Ocean and the spatial-temporal characteristics of the rainfall in eastern Amazon during the peak of the rainy season (February to April). The EOF results evidenced that the Intertropical Convergence Zone (ITCZ) is the main rainfall-producing system in eastern Amazon during the rainy season. Conditions associated with the southward SST gradient in the intertropical Atlantic formed the dynamic patterns that favored the position of the ITCZ to south of the equator, thus explaining the predominance of positive precipitation anomalies in eastern Amazon, especially in the state of Maranhão and northeastern Pará during the February and April months.

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

This study estimated the reference evapotranspiration rate (ETo) for the Itacaiúnas River Watershed (IRW), Eastern Amazonia, and measured the accuracy of eight empirical equations: Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves and Samani (HS), Camargo (CAM), Thornthwaite (TH), Hamon (HM), Kharrufa (KF) and Turc (TC) using monthly data from 1980 to 2013. In addition, it verifies the regional applicability to the IRW using a for the Marabá-PA station. The methods TC and PM (FAO56) presented the best results, which demonstrate that radiation and higher temperatures are the dominant drivers in the Evapotranspiration process, while relative humidity and wind speed have a much smaller impact. The temporal and spatial variability of ETo for IRW show has strong seasonality, increasing during the dry season and decreasing during the rainy season. The statistical analyses at 1% level of significance, indicates that there is no correlation of the residuals between the dry and rainy seasons, and test of the physical parameters such as mean temperature, solar radiation and relative air humidity explains the variations of ETo.

Impactos das mudanças climáticas na ecoclimatologia de Aleurocanthus Woglumi Ashby, 1903 (Hemiptera: Aleyrodidae) no estado do Pará

As atividades humanas que alteram as concentracoes de gases de efeito estufa terao influencias diretas sobre os problemas fitossanitarios. A fim de minimizar tanto a perda de producao, quanto a qualidade de safras, alem de orientar a escolha de estrategias de adaptacao e de gestao, novos estudos para investigar os impactos das mudancas climaticas na agricultura - nas escalas espaciais e temporais - e seus patogenos sao necessarios. O objetivo principal deste trabalho foi investigar o impacto da mudanca climatica global, na ecoclimatologia da mosca-negra-dos-citrus (Aleurocanthus woglumi Ashby) no Estado do Para. Para isso, foram analisadas as exigencias termicas da A. woglumi, desenvolvidas em laboratorio e no zoneamento ecoclimatologico, com base no numero de geracoes do inseto a cada ano, realizado a partir de dados de temperatura do ar de 15 estacoes meteorologicas ao longo do estado. Em seguida, foi simulado o aumento populacional de insetos estudados, atraves das projecoes do modelo climatico global CCSM 3.0, entre os anos de 2030 e 2090. Os resultados das simulacoes sugerem que o numero de geracoes do inseto vai aumentar 50% no Estado do Para.

Sensoriamento Remoto como Ferramenta para a Determinação da Estação Chuvosa na Amazônia (Remote Sensing as a Tool for Determining the Rainy Season in the Amazon)

A precipitacao e considerada a principal variavel meteorologica nos tropicos. Tal importância esta associada aos impactos sociais e economicos que sao gerados em extremos de ocorrencia dessa variavel. Diversos estudos para caracterizar a estacao chuvosa na Amazonica foram realizados, entretanto poucos consideraram os componentes de perdas hidricas, como a evapotranspiracao e a respectiva disponibilidade hidrica. O presente trabalho tem como principal objetivo, avaliar a metodologia proposta por Kassam (1979), para a determinacao do inicio e fim da estacao chuvosa, utilizando dados de 13 anos (2000 a 2012) de sensoriamento remoto de precipitacao e evapotranspiracao na Amazonia. Os resultados foram bastante consistentes com as analises existentes na literatura, sobre a dinâmica sazonal amazonica. Foi observado que o periodo chuvoso pode variar entre 4 a 7 meses entre as regioes sul e norte da Amazonia, respectivamente. No extremo oeste e notada uma estacao chuvosa continua. A B S T R A C T The precipitation is considered the main meteorological variable in the tropics. This importance is associated with social and economic impacts that are generated due occurrence of extremes. Several studies to characterize the rainy season in the Amazon have been applied, but few considered the components of water loss, such as evapotranspiration and their water availability. This study aims to evaluate the methodology proposed by Kassam (1979), for determining the begining and end of the rainy season, using data from 13 years (2000-2012) of remote sensing precipitation and evapotranspiration in the Amazon. The results were quite consistent with previous analyzes in the literature on the Amazon seasonal dynamics. It was observed that the rainy season can vary among 4-7 months between the southern and northern regions of the Amazon, respectively. In the far west portion is observed an permanent rainy season. Keywords: evapotranspiration, precipitation, seasonal rainfall .

Climatology of seasonal rainfall in the eastern Amazon

basins (Amazon, Tocantins/Araguaia and North-Northeast Atlantic) with focus on seasonal climatological patterns. The results showed statistically significant coefficients for both the satellite and analyzed data with reference to the observed data, so that the seasonal rainfall distribution evidenced better representations during rainy months (March to May) than dry months (September to November). In eastern Amazon, the portion of Brazil which has one of the lowest density of meteorological stations, both data sets are capable of reproducing the regional aspects of pluviometric variability, and the TRMM satellite estimates are relatively better than the CPC both in spatial and time resolution. Such knowledge on the comparison of meteorological data is important in several socio-economic activities in the region.