Topography-induced TKE budget behavior over an Amazon Forest

Data from three different heights (35, 50 and 81 meters) of one of the ATTO Project towers in the Amazon forest were used to calculate the TKE (turbulence kinetic energy) budget and some other statistics within the RSL (roughness sublayer). In addition, the results obtained from the data were compared with large eddy simulation (LES). The analyses were carried out for unstable and stable cases. The vertical turbulence transport (Tv) and the vertical advection (Av) terms do not explain the imbalances found in the TKE budget, highlighting the importance of horizontal terms in complex terrain. Indeed, patterns independent of the time of day were found for Tv, horizontal and vertical velocity skewness, the vertical component velocity (w), and momentum and vertical TKE flux. The highest values of w were observed from the direction where there is a valley near the tower, which may indicate a topographical effect. Monin-Obukhov Similarity Theory (MOST) predictions, strictly applicable only in the inertial sublayer (ISL), gave reasonable predictions at the 35 m level. At 81 m, there were clear deviations from MOST, disclosing the effect of topography. Finally, the results obtained with LES were in general agreement with tower observations.