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

Abstract

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 Corresponding author: Kun Yang, Dr., River Lab, Department of Civil Engineering, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-8656, Japan. E-mail: yangk@hydra.t.u-tokyo.ac.jp ( 2007, Meteorological Society of Japan 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 sufficient condition for a LSM to reproduce surface energy partition.

Some practical notes on the land surface modeling in the Tibetan Plateau

“…3, the peak of the daytime surface temperature for dry surfaces is significantly under-predicted by all models. In fact, this is a common issue for land surface modeling in arid and semiarid regions, as shown in Yang et al (2007). Many studies (e.g.…”

“…The data are provided by the CEOP (Coordinated Enhanced Observing Period) centralized data archive system . See Yang et al (2007) for a brief description of the models. Figure 1 shows that the surface energy budgets are quite discrepant among the four models from the pre-monsoon period (before DOY 151) to the monsoon period (after DOY 151), 2003.…”

Response of water budget to recent climatic changes in the source region of the Yellow River

“…With frequent rainfall events during the monsoon, latent heat flux overrides sensible heat flux and becomes the dominant surface heat flux. However, current models generally fail to reproduce surface fluxes over the TP because of unreasonable flux parameterization schemes [18]. An improved land surface model with a new flux parameterization scheme was recently applied on the TP surface, and the simulation was comparable to field observation [19].…”

Assessment of Energy Budget in Weather Forecasting General Circulation Models

“…Yang et al 8) summarized the results of a model inter-comparison study, based on multi-site and multi-month composite values of radiation, energy, water budget, and the diurnal cycle of precipitation. In this study, we focus on energy budget and give more detailed analysis at individual reference sites.…”