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

Abstract

The present study considers the mean wind velocity profiles measured from a 60 m high tower in the Rebio-Jarú forest (10 ° 04.7 ′ S, 61 ° 52.0 ′ W), located in the Brazilian northwestern state of Rondônia. 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, ū(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 ū(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. © 2015 Royal Meteorological Society