Eiky Moraes, Cléo Dias-Júnior and their colleagues wanted to find out if the local topography at the ATTO influenced the atmospheric movements. In particular, they were interested in the effect that topography has on the formation of gravity waves. Comparing two simulations, one with and one without topography, revealed some important differences in the dynamics and chemistry of the atmosphere.
Only when the air inside of the forest canopy mixes with the air above can there be exchange. The physical movement of the air, its turbulence, determine how well these two layers of air, the one inside the forest canopy and the one above, mix. Daniela Cava, Luca Mortarini, Cleo Quaresma and their colleagues set out to address some of these questions with two new studies that they conducted at ATTO. They wanted to define the different regimes of atmospheric turbulence or stability (Part 1) and describe the spatial and temporal scales of turbulent structures (Part 2).
In a new study, Marco A. Franco and his colleagues analyzed when and under what conditions aerosols grow to a size relevant for cloud formation. Such growth events are relatively rare in the Amazon rainforest and follow and pronounced diurnal and seasonal cycles. The majority take place during the daytime, and during the wet season. But the team also discovered a few remarkable exceptions.
It is long known that aerosols, directly and indirectly, affect clouds and precipitation. But very few studies have focused on the opposite: the question of how clouds modify aerosol properties. Therefore, Luiz Machado and his colleagues looked into this process at ATTO. Specifically, they studied how weather events influenced the size distribution of aerosol particles.
Polari Corrêa and his co-authors analyzed the atmospheric dynamics in and above the forest canopy during one particular night at ATTO. Those conditions changed throughout the night. Turbulence was followed by the formation of a gravity wave and a low-level jet. It was likely formed due to the breeze from the Uatumã River and the hilly terrain. The study highlights the complex dynamics and mechanisms in the atmosphere above a dense forest.