Initial CEOP-based Review of the Prediction Skill of Operational General Circulation Models and Land Surface Models

抄録

Using data archived in the Coordinated Enhanced Observing Period (CEOP) project, this study presents an initial evaluation of the prediction skill of five General Circulation Models (GCMs) and three Land Surface Models (LSMs). Comparisons between observations and the GCMs show that all the models are able to produce an afternoon peak in precipitation, but other major features are not well produced, including the total amount of precipitation, onset time of the afternoon peak, the early-evening low (around 1800 LST), and the partition between convective and stratiform rainfall. The ratios of evaporation to precipitation differ among the GCMs. Evaporation in some of the GCMs is even greater than precipitation, perhaps due to the model spin-up effect. In terms of the surface radiation budget, the GCMs generally over-predict downward shortwave radiation and under-predict downward longwave radiation; further investigations of the causes of these trends require cloudiness observations. In terms of the surface energy budget, the GCMs generally over-predict nighttime downward sensible heat fluxes and under-predict diurnal ranges of surface-air temperature difference, as heat transfer resistances are under-predicted. Finally, three offline LSMs driven by identical forcing are evaluated, and we note that the reproduction of surface temperature is not a suflicient condition for a LSM to reproduce surface energy partition.