Radiative effects of precipitation on the global energy budget and Arctic amplification

Abstract

Radiative forcing is an essential metric for accurate climate prediction. Clouds are a well-known source of uncertainty, but the radiative effects of precipitation (REP) are poorly understood and excluded from most general circulation models (GCMs). This is because conventional GCMs treat precipitation diagnostically, and thus, are transparent to shortwave and longwave radiation. In this study, we investigated the REP at global and regional scales by employing three sub-models incorporating (1) diagnostic precipitation, (2) prognostic precipitation without REP, and (3) prognostic precipitation with REP. We found that REP alters not only the local thermodynamic profile but also the remote precipitation rate and distribution through changes in atmospheric circulation. The polar surface temperature increases by more than 1 K in the winter when considering REP. The 34 CMIP6 models show systematic differences in Arctic amplification depending on REP, emphasising that GCMs should include REP to improve confidence in simulating atmosphere-ocean-cryosphere interactions.