CloudRoots-Amazonia22: Integrating clouds with photosynthesis by crossing scales

How are carbon dioxide assimilation by photosynthesis and (shallow) cumulus clouds connected? What is the local interaction between rainforest evapotranspiration and cloud formation modulated by incoming regional air masses? These interrelated questions were the main drivers of the experimental campaign CloudRoots-Amazonia22 that took place at the ATTO/Campina supersites in the pristine Amazon rainforest during August 2022 (dry season). CloudRoots-Amazonia22 collected observational data to derive relationships between leaf level processes to canopy scales and connected them to the diurnal evolution of the clear to cloudy atmospheric boundary layer. At leaf level, first results indicate a diurnal asymmetry of the leaf conductance with maximum openings before midday. These observations are related to radiative energy fluxes to study the partitioning into sensible and latent heating and of plant-soil carbon dioxide exchnages. By coupling measurements of carbon and water stable isotopologues by fast laser instruments to turbulence measurements we aim to quantify flux variations related to the radiation fluctuations driven by clouds. These observations are integrated with 75 soundings of state variables and greenhouse gas profiles taken by flights below, through and above the cloud layers. We investigate what controls the transition from shallow to deep convection and the causality between the surface-cloud shear and the moisture transport at the interface between the different atmospheric layers. The observational analysis is completed with conceptual modelling and systematic large-eddy simulation experiments, which include dynamic vegetation models to advance our understanding of the diurnal energy, water and carbon cycles over the Amazon rainforest.