Resolution Dependence of the Climate Feedback Parameter in Km‐Scale Climate Models

Abstract

Global storm‐resolving models (GSRMs) provide new opportunities to investigate the climate response to warming with explicitly resolved deep convection. However, the limited number of existing studies has so far precluded the systematic assessment of similarities and differences across GSRMs. Here, we compare the Cess sensitivity (the climate sensitivity estimated from the response of atmospheric radiation budget to uniform surface warming) of the ICOsahedral Nonhydrostatic (ICON) model with three other GSRMs and CMIP5/6 models, using AMIP and aquaplanet model experiments under uniform warming (+4 K). We find that the Cess sensitivity across GSRMs at their finest horizontal resolution ranges from 2.2 to 3.3 K, comparable to that of CMIP6 models. In ICON, the negative net climate feedback parameter and its longwave component both decrease with finer resolution, while the positive shortwave component increases. The resolution dependence of the longwave and shortwave components originates primarily from the tropics and the Northern Hemisphere extratropics, respectively.