Dinâmica do escoamento de ar acima e dentro de uma floresta tropical densa sobre terreno complexo na Amazônia : aspectos observacionais e de modelagem

Abstract

This paper has been divided from two sections: modeling and observational. In observational study used data from a field campaign conducted in 2006, in the Biological Reserve of Rio Cuieiras - ZF2, near the Manaus city (Amazonas), with the aim of to report the flow below the canopy, and determine their ration to the wind above the forest. We measured horizontal and vertical gradients of air temperature and wind during the 2006 dry and wet seasons. The results shows, in general, the frequency of winds, both above and below the canopy is higher in the dry season reaching 73.5% and 84% respectively. There is also a flow pattern below the forest, persistent and systematic, on the slope area, up at overnight and down during the diurnal and disengaged with the air above the canopy, this flow pattern is opposite to the classic pattern mountain-valley flow. The average vertical gradient of θv was negative at night and positive during the day in both seasons. Showing the topography and thermal structure inside the forest is responsible for this reverse flow pattern along the hillside. In the second section was evaluated performance of Yi et al. (2005, 2008) analytical model, to estimate the wind profile inside the forests on sloping area. The values of some parameters were extracted from the literature and an equation was developed to estimate the vertical profile of the coefficient of drag. The behavior of the wind profile throughout the day and night showed a clear attenuation of the top into the forest similarly a high pass filter. The dependent component of the topography and the thermal regime within the forest, clearly predominates at night and have more influence in the profile at the lower levels. Note that the lower levels of the forest, the profiles had provided overnight (negative) characteristics observed runoff drainage, climbing the slope at lower levels of the forest and down in the layer immediately above and 15 meters tall.