Turbulence regimes over the Amazon Forest

Our goal is the detailed characterization of turbulence regimes at the ATTO tower site. This includes both nighttime (very stable or weakly stable) and daytime (mixed or forced convection). We will characterize them in terms of parameters that are external to the planetary boundary layer (PBL), such as large-scale wind forcing, radiative processes, roughness and thermal surface properties. This is important because internal parameters, commonly used for that purpose, are affected by the same problems that make turbulence regime determination difficult, such as the lack of turbulence in the very stable case or its peculiar geometry in free convection. With this analysis, we will also address the effects of the turbulence regimes in the vertical profiles of concentration and fluxes of the different chemical species that are measured at the ATTO tower. We will then compare the relationships found with analyses we performed at other places. Our aim is to generalize the dependence of the turbulence regimes on parameters that are external to the PBL in a quasi-universal way. The final goal is to implement the general relationships found between fluxes and gradients of mean quantities in numerical schemes for the interaction between the forest and the atmosphere.