Incoming Shortwave Fluxes at the Surface—A Comparison of GCM Results with Observations

Evidence is presented that the excess surface net radiation calculated in general circulation models at continental surfaces is mostly due to excess incoming shortwave fluxes. Based on long-term observations from 22 worldwide inland stations and results from four general circulation models the overestimate in models of 20% (11 W m−2) in net radiation on an annual basis compares with 6% (9 W m−2) for shortwave fluxes for the same 22 locations, or 9% (18 W m−2) for a larger set of 93 stations (71 having shortwave fluxes only). For annual fluxes, these differences appear to be significant.