Relações de similaridades associadas ao campo de velocidade do vento acima e dentro do dossel da floresta amazônica sob a influência de instabilidade do ponto de inflexão

Abstract

The aim of this study is to further investigate the transitional roughness sublayer above the Amazon terra firme rainforest. Turbulent vertical profiles of wind speed collected at a 60-meters-high tower in the Biological Reserve of Jarú (Rebio Jarú), Ji-Paraná-RO, are analyzed. The experimental site is characterized by the native tropical forest with an average height of 33 meters, with some species reaching up to 45 meters height. The Wavelet Transform analysis has provided a useful tool to project the wind field by scale, and so, to explain the filtering effect of the atmospheric flow by the forest canopy, under unstable and stable conditions, with strong, moderate and weak wind situations. So, it has been possible to investigate which scale are most affected by the filtering process of the turbulent kinetic energy by the forest canopy. It has been observed that the energy filtering was more effective in situations of weak winds in the largest time scales studied. Furthermore, we seek to improve existing formulations for the vertical profile of average wind speed above and within the canopy using, for example, the hyperbolic tangent function. More realistic fitted functions of the vertical profiles of the mean wind available have been obtained through the use of several improvements of the hyperbolic tangent function, so that it permits to explain situations characterized by the occurrence of relative maximum wind speed near the surface. These results have suggested that it is possible to obtain good fitted functions for much of the analyzed data.