Midlatitude Cloud Radiative Effect Sensitivity to Cloud Controlling Factors in Observations and Models: Relationship with Southern Hemisphere Jet Shifts and Climate Sensitivity

Abstract An effective method to understand cloud processes and assess the fidelity with which they are represented in climate models is controlling factor framework, properties linked variations large-scale dynamical thermodynamical variables. This study examines how midlatitude radiative effects (CRE) over oceans co-vary four factors: mid-tropospheric vertical velocity, estimated inversion strength (EIS), near-surface temperature advection, sea surface (SST), assesses their representation CMIP6 respect observations CMIP5 models. overestimate sensitivity of CRE perturbations underestimate shortwave EIS advection. The largest improvement a reduced velocity perturbations. As models, many simulate warming effect associated poleward shift Southern Hemisphere (SH) jet stream, an not present observations. bias arises because most models’ too sensitive enough perturbations, SST anomalies SH shifts. presence this directly impacts transient response increasing greenhouse gases Ocean, but global-mean temperature. Instead, correlated advection near 40°S, more realistic values generally having higher sensitivity.