Evaluation of the Decadal Prediction Skill over China Based on Four Global Atmosphere－Ocean Coupled Climate Models
摘要: 利用4个海气耦合模式对1960～2005年的多年代际回报结果，评估模式对中国区域年代际气候变化（温度和降水）的预测潜力，并初步给出2005～2015年的气候预测结果。与CMIP3多模式集合1960～2000年结果以及观测实况比较的结果表明：融入观测资料进行同化的年代际气候预测模式，对中国区域温度和降水的模拟能力总体好于CMIP3模式。年代际气候预测模式对温度气候场的模拟仍以“冷偏差”为主，但较之CMIP3模式已有显著改进，中国区域平均的冷偏差减少1.3 °C；对降水气候场的模拟仍以“湿偏差”为主，但在华南沿海和西北内陆降水的模拟能力优于CMIP3模式，中国区域平均的湿偏差降低了20%。年代际模式和CMIP3模式都能较好地模拟出中国区域尤其是北方20世纪后期的增暖信号；但 CMIP3模式对20世纪后期中国东部降水的旱涝结构演变的模拟与观测相反；而年代际气候预测模式未能再现华北偏旱的变化，但能成功地模拟江淮流域和华南沿海的旱涝演变。2005～2015年的10年预测表明中国区域将继续增暖0.3～0.7 °C，且增温幅度北方大于南方，增幅中心位于西北内陆和青藏高原；而降水的变化趋势不显著，黄淮地区、西北内陆和青藏高原的降水略有增加，而西南地区降水将减少。但需要指出的是，这种预测的不确定性是相当大的。
Abstract: 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 Chinaaveraged 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.
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