Abstract
The newest atmospheric climate model at GFDL, AM4, succeeded at
significantly reducing the toa radiative flux biases as compared to
CERES observations. Despite a relatively low top-of-atmosphere
sensitivity to uniform warming of SSTs (Cess warming experiments), the
corresponding coupled climate model, CM4, has high transient and
equilibrium climate sensitivities. We will present a systematic picture
of the modeled clouds across a hierarchy of model configurations which
utilize this atmospheric model. This hierarchy includes the CFMIP
Aquaplanet and AMIP experiments, fully coupled model experiments (using
GFDL’s CM4 model) as well as additional AMIP-like experiments with
particular SST patterns. This demonstrates the large range of
sensitivities that are possible from a single atmospheric climate model.
Looking at the global mean radiative feedbacks across the different
model configurations as well as in the context of CMIP5 and CMIP6 models
will allow us to assess to what extent the cloud feedbacks in the
idealized experiments relate to the fully coupled experiments and to
observed clouds.