Abstract
O objetivo deste trabalho é estudar o balanço hídrico na Bacia Amazônica Brasileira no período de 1982-2012; determinando a vazão referência de cada sub-bacia; determinando a influência dos fenômenos El Niño e La Niña no balanço hídrico; além das diferenças desse balanço ocorridas entre as sub-bacias da margem esquerda e margem direita. A importância desse estudo deve-se ao fato que a Região Amazônia comporta a maior florestal tropical e a maior bacia hidrográfica do mundo, suprindo as necessidades de umidade do resto do pais. Contudo o desmatamento da floresta e a ocorrência de eventos extremos de precipitação modificam o ciclo hidrológico, interferindo na precipitação, vazão e evaporação. Nesse estudo foram utilizadas 224 estações pluviométricas e a vazão de referência em 8 sub-bacias, do rio Solimões, Negro, Trombetas, Jari, Purus, Madeira, Tapajós e Xingu. Assim este estudo encontrou resultados importantes, onde a taxa de evaporação a partir da precipitação teve valores entre 58 e 62% entre as calhas sul e norte, respectivamente, além disso em média a evaporação teve uma tendência positiva ao longo do período estudado mostrando que durante o El Niño essa taxa é maior na margem esquerda e menor na margem direita. A B S T R A C T The present work aimed at studying the water balance in the Brazilian Amazon Basin in the period from 1982 to 2012; by determining the reference flow of each sub-basin; by determining the influence of El Niño and La Niña phenomena in the water balance; as well as the differences of this balance that occurred between the sub-basins of the left and right banks. The importance of this study is due to the fact that the Region Amazon houses the largest tropical forest and the largest river basin in the world, supplying the humidity needs of the rest of the country. However, deforestation and the occurrence of extreme events of precipitation change the hydrological cycle, affecting the precipitation, flow and evaporation. In this study, 222 rain stations were utilized, as well as the reference flow of 8 sub-basins of rivers Solimoes, Negro, Trombetas, Jari, Purus, Madeira, Tapajós and Xingu. Thus, this study found significant results, where the rate of evaporation resulting from precipitation had values between 58% and 62% between the northern and southern channels, respectively. Moreover, on average, evaporation had a positive tendency over the studied period showing that during El Niño, this rate is higher in the northern channel and lower in the southern rail.Key words: extreme events, precipitation, flow and evaporation.
Highlights
According to studies like de Rocha (2004) 70% of the total surface of the Earth, approximately 581 million km2, consists of water, and the oceans are the main sources of water vapor for the global atmosphere
When it comes to the right edge of the subbasins, Punis Wood Tapajós and Xingu realizes the same relationship between precipitation and flow, but in all of them evaporation was higher than the flow rate ranging from 960 to evaporation of 1250 mm and 720 to 870 mm flow rate
The bowl and Solimoens Tapajós sub-basins, and Black Xingú presented above the average of the remaining 58% and below, showing that there is a balance between them, as mentioned by(E⁄P)Callède et al (2002) and Satyamurty et al (2013), who claim that the Amazon has great regularity in the annual hydrological regime, where the sub-basins of the drought are compensated by the other sub-basins that are in season full
Summary
According to studies like de Rocha (2004) 70% of the total surface of the Earth, approximately 581 million km, consists of water, and the oceans are the main sources of water vapor for the global atmosphere. Brazil has 11.6% of all the world's fresh water and the Amazon region contributes about 70% (Rocha, 2004). Marengo (2006) states that the availability of water in Brazil depends largely on the weather and the type of ground cover, where the plant samples of forests carry water from the soil into the atmosphere. The energy required (sweating) to turn water into steam may represent 50% of the precipitation. The variability of precipitation and flow in the Amazon basin are issues of major concern, due to the deforestation of burning, the extremes (drought and flooding) and meteorological phenomena, such as El Nino, causing the dry, forest fires ( Fearnside, 2009) and La Niña, which unlike raises rainfall, causing floods, leaving whole riverside populations homeless
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