Two micrometeorological towers located in the experimental site of Pedras Altas in the region of Pampa Gaúcho were separated by a distance of about 500 m from each other, enabling a small scale horizontal variability, due to the complexity of the terrain. Such variability favors distinct contributions in the modes of flow. This work points out a relation between classes of maximum wind measured in the station of the top of the hill with obstructions provoked by the heterogeneity of the terrain. Through a spectral analysis it was possible to find encouraging results for future work, as the study shows a pertinent relation between non-turbulent low frequency motions with surface heterogeneity and how this implies in the horizontal and vertical turbulent velocity.
