Evaluation of the Decadal Prediction Skill over China Based on Four Global Atmosphere－Ocean Coupled Climate Models

By using the results of multi-decadal hindcast (1960－2005) of four atmosphere－ocean coupled models, the decadal predict skill of temperature and precipitation over China is evaluated, and the predicted climate change of 2005－2015 is also provided. Both the multi-decadal hindcast results and the simulations of 22 CMIP3/IPCC AR4 22 models which have no initialization, are compared to observations. The results show that generally the coupled models which have the assimilation of observational data into decadal prediction outperform the CMIP3/IPCC AR4 general circulation models with no initialization. For temperature field, the decadal climate models still have “cold bias”. However, the bias is lower than the CMIP3 multi-model ensemble (MME), for example the Chinaaveraged cold bias reduces 1.3 °C; With respect to the precipitation field there is still “wet bias” in most parts of China, however, over the South China and the inland northwestern part of China the skill of the four decadal prediction models is better than that of the CMIP3 MME. The China-averaged bias for precipitation in the decadal prediction models is lower than CMIP3 MME by 20%. Both of the four decadal prediction models and the CMIP3 MME can simulate warming signal in the late 20th century over China, especially in the northern part. The CMIP3 MME can not reproduce the pattern of “wet South and dry North” in the eastern part of China in recent 20 years. In contrast, the four decadal prediction models show better agreement with observations in simulating the pattern of “wet South” in China in recent 20 years, although they still can not reproduce the pattern of “dry North”. The prediction results for 2005－2015 show that the temperature over China will continue to increase by 0.3－0.7 °C, and the magnitudes of this increase are greater in northern part than in southern part, with the largest change locates in the Tibetan Plateau and the northwestern part of China，and the trends of precipitation are not significant. There is a slight increase in the Huanghe－Huaihe region, the northwestern part of China, and the Tibetan Plateau, while in the southwestern part of China the precipitation will decrease. It should be pointed out that the uncertainty is quite great for this prediction.