Project description

Climate models widely disagree on how tropical low-level clouds will respond to climate warming, causing large uncertainty in climate sensitivity estimates. The underlying reason for the models’ disagreement is a poor understanding of processes of shallow convection, in particular on scales that remain unresolved in current climate simulations. The proposed International Team aims to understand the mesoscale processes that couple trade-cumuli to circulations in order to constrain their feedback, with a focus on the spatial patterning of these clouds — a largely ignored feedback component. The team will use novel field measurements of clouds and circulation, satellite observations, and large-eddy simulations to identify these processes. The ultimate goal is to improve climate sensitivity estimates by using this process-understanding to constrain the wide-range of cloud feedback provided by climate models. The expected outcomes of the study are several articles describing mesoscale processes and a joint reference data-set providing regional mesoscale quantities for the modelling community to validate their simulations. With the help of this data-set the team will disentangle the trade-cumulus feedback into its individual components, and provide a basis for future investigations. The team will meet twice in Bern, Switzerland, once each in 2023 and 2024.