Influência do Corte de Impacto Reduzido nos Fluxos de Energia na floresta Manejada no Leste da Amazônia

Inúmeras atividades econômicas estão adentrando na região Amazônica, provocando alterações que tornam imprevisíveis a intensidade dos impactos causados por esse novo ciclo de produção. Com isso, os fluxos superficiais de energia e massa, variam bastante, induzindo mudanças no clima local [1][2]. Este trabalho objetivou verificar a influência do manejo florestal nos fluxos turbulentos de calor latente (LE) e calor sensível (H) na Floresta Nacional do Tapajós na Amazônia oriental na região de Santarém-PA

A ALCALINIDADE PODE SER UTILIZADA PARA ESTIMAR A CONCENTRAÇÃO DE CARBONO INORGÂNICO DISSOLVIDO NO RIO AMAZONAS?

 Este trabalho analisou concomitantemente as concentrações de carbono orgânico (COD) e inorgânico (CID) dissolvidos no Rio Amazonas no Estreito de Óbidos. As amostragens foram realizadas mensalmente de janeiro a dezembro de 2015. Observou-se que a alcalinidade é composta por cerca de 19 ± 11% compostos não carbonatos. Utilizando-se da concentração de CID e pH estimou-se que a pressão parcial de CO2 (pCO2 ) foi em média 4691± 1135 µatm, a concentração de bicarbonato (HCO3) no rio foi em média 316±71 µmol.L-1 e a concentração de CO2 dissolvido (CO2*) foi 135±35 µmol.L-1. Os valores de pCO2, HCO3 e CO2* calculados com base na alcalinidade e no pH apresentaram valores médios de 7133 ± 2758 µatm, 375 ± 50 µmol.L-1 e 215 ± 50 µmol.L-1 respectivamente. Os valores estimados com baseada na alcalinidade e foram estatisticamente diferentes dos valores concentrados com o uso da concentração de CID (teste T pareado). Portanto, no canal principal do Rio Amazonas, a alcalinidade não é um parâmetro robusto na estimativa de pCO2 ou espécies químicas de CID. Os valores de todos os parâmetros analisados são semelhantes aos encontrados na literatura, sugerindo que não as transformações que vêm ocorrendo ao longo da bacia de drenagem, a monte de Óbidos, não foi suficiente para alterar as concentrações de CID e COD em larga escal

Concentração e fluxo de CO2 sobre o reservatório hidrelétrico de Balbina (AM)

The reservoir Balbina (59º 28’ 50w, 1º 53’ 25” S), located near the city of Manaus, Amazonas, in Central Amazônia, Brazil, is the second largest hydroelectric reservoir in an area located in the Amazon Basin. In this reservoir, CO2 measurements were performed at high frequency (10 Hz), CO2 flux with gas analyzer infrared (IRGA) coupled to a floating chamber and meteorological variables with a buoy instrumented to 2 m from the lake surface. The average CO2 concentration was 392 and 426 ppm for the day and night, respectively, and the daily average emission rate was 40.427±24.040 μmol-1.m-2.d-1. The accumulation of CO2 in the lake overnight, beyond respiration, shows to be affected by low wind speeds, waterside convection, physical processes involving high concentrations of CO2 for the surface and the presence of land breeze. The fluxes show no statistically significant difference with the meteorological variables and were considerably lower than a previous study for the same lake. However, the values are in agreement with other studies in Amazonian tropical lakes and other reservoirs. © 2017, ABES - Associacao Brasileira de Engenharia Sanitaria e Ambiental. All rights reserved

Solar Ultraviolet Radiation Temporal Variability Analysis from 2-Year of Continuous Observation in an Amazonian City of Brazil

International audienceSolar ultraviolet radiation (UVR) is a highly energetic component of the solar spectrum that needs to be monitored because of the effects on human health and on the ecosystems. In Brazil, few cities monitor UVR, especially in the Amazon region which is particularly poor in observation. This work is the first to address the short-term (2-year) time variability of UVR in Santarém (2°25′ S, 54°44′ W, 51 m) using ground-based measurements. The irradiance in the wavelength range of 250–400 nm was investigated on different time scales. Furthermore, to understand how the UVR varies without the influence of clouds, the hours corresponding to the clear sky condition were analyzed as well as the hours in all sky conditions. Regarding the averages, there is a slight variation over the year. In all sky and clear sky conditions, the dry season had a higher average than the rainy season, despite the slight difference. Also, both in all-sky and clear-sky conditions the maximums occurred around local solar noon, and reached a maximum of 87 W/m2 in the dry season under the clear sky condition. Further understanding of the radiative effects of the clouds in UVR time variability is considered essential for future research. This study can serve as a reference for UVR levels in this region where no other ground-based UVR measurements are made

Concentração e fluxo de CO2 sobre o reservatório hidrelétrico de Balbina (AM)

The reservoir Balbina (59º 28’ 50w, 1º 53’ 25” S), located near the city of Manaus, Amazonas, in Central Amazônia, Brazil, is the second largest hydroelectric reservoir in an area located in the Amazon Basin. In this reservoir, CO2 measurements were performed at high frequency (10 Hz), CO2 flux with gas analyzer infrared (IRGA) coupled to a floating chamber and meteorological variables with a buoy instrumented to 2 m from the lake surface. The average CO2 concentration was 392 and 426 ppm for the day and night, respectively, and the daily average emission rate was 40.427±24.040 μmol-1.m-2.d-1. The accumulation of CO2 in the lake overnight, beyond respiration, shows to be affected by low wind speeds, waterside convection, physical processes involving high concentrations of CO2 for the surface and the presence of land breeze. The fluxes show no statistically significant difference with the meteorological variables and were considerably lower than a previous study for the same lake. However, the values are in agreement with other studies in Amazonian tropical lakes and other reservoirs. © 2017, ABES - Associacao Brasileira de Engenharia Sanitaria e Ambiental. All rights reserved