Navegando por Assunto "Fluxo de calor"

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Acesso aberto (Open Access)
Balanço de energia e fluxos turbulentos associados à fatores físico-químicos da água na baía de Caxiuanã
(Universidade Federal do Pará, 2014) PINHEIRO, Amanda Nascimento; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
Investigate the behavior of the energy balance on water surfaces is still a scientific challenge, since few studies are available on this topic in this type of surface. The flona of Caxiunã several years ago has become a major object of study for various field of science that support for the Amazon region. Among these fields lies the micrometeorology, which discusses among his main topics of interest are the phenomena of energy and mass exchange at the surface-atmosphere interface. Aiming to fill this lack of information, in this study the hourly and seasonal variations of the components of energy balance, such as latent heat and sensible heat flux were analyzed. With the assist of meteorological variables such as precipitation, air temperature, wind speed and direction as well as physical- chemical water parameters (albedo, tide level, turbidity, water temperature and amount of total organic and inorganic carbon) was studied the role of these variables in the energy balance in the Caxiuanã bay. A peculiarity presented by Caxiuanã bay was the water temperature always being higher than the air temperature values, demonstrating that the bay can hold large amounts of heat during the day and not lose most of this heat to the atmosphere during the night. The total organic carbon present in the waters of the bay decreased concentration throughout the study period. The latent heat flux (LE) was shown to be the dominant component of the energy balance, presenting an average value of 200 W.m-2 during most of the study period, and the sensible heat flux (H) showed a peak in May with about 50 W.m-2. The negative values of H during the nighttime show that the bay is losing heat to the environment, ie, the bay is acting as a heat source for local atmosphere, including the forest.
Acesso aberto (Open Access)
A influência da variabilidade espacial e sazonal sobre o efluxo de dióxido de carbono do solo em ambientes modificados na FLONA Caxiuanã-PA
(Universidade Federal do Pará, 2014) TEIXEIRA, Ana Paula Assunção; CATTANIO, José Henrique; http://lattes.cnpq.br/1518769773387350
This study aimed to investigate the influence of spatial and seasonal variability on the efflux of CO2 from the soil to the atmosphere by comparing with heat sensitive streams and latent heat as with the environmental variables (air and soil temperature, relative humidity and volumetric soil moisture) and total organic carbon in soil. This study was conducted in environments modified naturally (AMN) and antropicamente (AMA) on the FLONA of Caxiuanã, PA, during the transitional period of rainy-dry season and dry period in the year 2013. We have seen that the opening of anthropogenic and natural gaps promote variations of environmental factors arriving at the interior of the modified environments, causing greater intensity in the heat flux, favoring thus the spatial variability of CO2 efflux. The AMN showed an increase of CO2 efflux from the period of transition from the rainy–dry season to the dry period, where the highest rates of efflux occurred in the afternoon with the removal of the gap to the interior of the forest under closed canopy in east and west the gap. Contrasting with the AMA where it was verified reduction of rates of efflux of the transitional period of rainy– dry season to the dry period. Correlations between soil temperature and soil moisture with the CO2 efflux presented significant correlation mainly in the center of the gaps, influenced by heat transport more intense at this location. In this way, the CO2 efflux receives influence of environmental micrometeorological variables, soil physical and chemical characteristics and contribution of total organic carbon, showing variations of behavior with the opening of natural gap and anthropized in the Amazon rainforest.