Turbulent Fluxes Within and Above the Amazon Roughness Sublayer

For tropical forests, such as the Amazon Forest, the turbulence intensity at the forest-atmosphere interface is high since in this region there is strong convective activity during the day and the aerodynamic roughness of the forest canopy is high. Heat and other scalar properties are exchanged between the flow and the canopy. Understanding these exchange mechanisms is essential for a variety of applications in various fields of science. Furthermore, it is known that the Amazon region has a strong influence on the transport of heat and water vapor to regions located at higher latitudes and plays an important role in the carbon cycle. Measurements carried out in micrometeorological towers are crucial for the correct quantifications of the turbulent fluxes. However, the use of micrometeorological towers in the Amazon is recent. High frequency measurements (eg Eddy covariance systems) in the Amazon rainforest were usually performed at a single point, often above the forest canopy. The first analyses from the fast response data clearly showed the existence of what is now known as the roughness sublayer (RSL). In these works, it was speculated that the surface boundary layer, was higher up. Within Amazonian RSL, important discoveries have already been made, for example: (i) the Monin-Obuhkov similarity functions are not the most appropriate for estimating turbulent fluxes in the region immediately above the forest canopy. (ii) The Amazonian nocturnal boundary layer is often populated by submeso phenomena, which create episodes of intermittent turbulence and increase the complexity of exchange processes between the forest and the atmosphere during the night. (iii) Above the Amazonian RSL, it was possible to verify that there is no evidence of a classic inertial layer. Since July 2021, the ATTO (Amazon Tall Tower Observatory) tower has been performing continuous measurements, carried out by nineteen 3D-sonic installed from 5 m (inside the forest canopy) to 316 m (above the RSL). Therefore, in this work we will show the profiles of different turbulent fluxes measured since mid-2021 under different stability conditions and at different periods of the year (dry and rainy season). These new measurement profiles, with high vertical resolution, are unique and they will allow us to understand the turbulent exchange processes in regions of the Amazon planetary boundary layer that have not been previously explored.