An empirical-analytical model of the vertical wind speed profile above and within an Amazon forest site

摘要

The present study considers the mean wind velocity profiles measured from a 60m high tower in the Rebio-Jaru forest (10 degrees 04.7S, 61 degrees 52.0W), located in the Brazilian northwestern state of Rondonia. The data were collected during the wet season as part of an intensive campaign of the large scale biosphere-atmosphere experiment in Amazonia. Nine cup anemometers were vertically placed to provide a good estimate of the inflection point height of the mean wind velocity profile. The resulting data were used to formulate a mean vertical wind speed profile, (u) over bar (z), based on key parameters such as the inflection point height and the leaf area index. The modified hyperbolic tangent function was used to provide a more flexible fit to the experimental data. An exponential term was also added to the (u) over bar (z) function, so that it can assume the appropriate s' shape near the ground. Thus, some parameters were incorporated into the analytical profile function to enable more flexibility. The presented results demonstrate that the profile is a good fit to the experimental data measured above and within the Amazon forest canopy.