Regional Fast Cloud Feedback Assessment As Constraint on Global Climate Sensitivity

Abstract:

Uncertainty in climate sensitivity estimates from models relates to inter-model spread in cloud-climate feedback. A sizeable component of the cloud-climate feedback is due to fast adjustments to altered CO2 profiles. This suggests the emerging large-domain season-long cloud-resolving simulations might become useful as reference simulation when performing sensitivity simulations with doubled CO2 concentrations. We assessed the fast cloud feedback in the CMIP5 multi-model ensemble of general circulation models (GCM) to find that in the chosen example region of Central Europe the fast cloud feedback behaves similarly as it does over global land areas in indivual models, yet shows a large inter-model scatter. This result is discussed with respect to the question whether a regional high-resolved model might be suitable to constrain global cloud feedbacks.