Climate Forcings and Climate Sensitivities Diagnosed from Coupled Climate Model Integrations

摘要: A simple technique is proposed for calculating global mean climate forcing from transient integrations of coupled atmosphere–ocean general circulation models (AOGCMs). This “climate forcing” differs the conventionally defined radiative as it includes semidirect effects that account certain short time scale responses in troposphere. First, a feedback term calculated reported values 2 CO2 and surface temperature series 70-yr simulations by 20 AOGCMs. In these carbon dioxide increased 1% yr 1 . The derived agrees well with are diagnosed equilibrium change experiments slab-ocean versions same models. These terms associated fast, quasi-linear response lapse rate, clouds, water vapor, albedo to changes. importance feedbacks gauged their impact on fluxes at top atmosphere. Partial compensation found between longwave shortwave lessens intermodel differences sensitivity. There also some indication AOGCMs overestimate strength positive feedback. then used infer twentieth- twenty-first-century validated using four forcings agree conventional within 10%. exhibit order magnitude variations AOGCMs, likely related how both natural and/or anthropogenic aerosol included. factor series, which may indicate problems modeling well-mixed greenhouse gas diagnoses presented provides an important useful first step understanding AOGCM integrations, indicating model projections can be attributed different prescribed forcing, even so-called standard scenarios.