Impact of Turbulence on the Relationship between Cloud Feedback and
Aerosol-Cloud Interaction in an E3SMv2 Perturbed Parameter Ensemble
Abstract
Recent studies reveal an anti-correlation between global cloud feedback
(CF) and effective radiative forcing due to aerosol-cloud interaction
(ERFaci) in climate models, but its physical plausibility remains
uncertain. Here we investigate whether different turbulence
representations, specifically through perturbing turbulence parameters,
contribute to this relationship over the global ocean using an E3SMv2
perturbed parameter ensemble. The anti-correlation appears only in the
tropical ascent regime. In the Northern Hemisphere midlatitude and high
latitude regimes, there is no significant correlation, and in the
tropical marine low cloud and Southern Ocean regimes, the correlation is
positive. These opposite correlations are primarily driven by opposing
CF responses to perturbed parameters. We find that the mean-state
turbulent mixing strength affects both CF and ERFaci, enabling strong
correlations in certain regimes. This study highlights the complex
linkages between CF and ERFaci through turbulent processes across
diverse cloud regimes.