BCC第二代气候系统模式对东亚夏季气候预测能力的评估

Evaluation on the Performance of BCC Second-Generation Climate System Model for East Asian Summer Climate Prediction

基于国家气候中心第二代气候系统模式的回报和实时预测数据,利用同期和滞后相关、偏相关分析以及联合EOF分解等方法,评估了其对夏季东亚环流和降水的预测能力。结果表明,模式对高低层环流和降水气候态的空间分布形势,特别是强降水中心和季风系统成员位置的预测较为合理,但存在一定的系统性偏差。模式对于东亚特别是中国大陆地区夏季降水年际变化的预测能力较弱,但对于东亚500 hPa高度场年际变化的预测效果较好,并且随着起报月的临近,技巧有所改进,此外模式对于东亚夏季气候变率主要模态的时空分布特征具有较高的预测技巧。模式较好地反映出了东亚夏季气候对El Nino发展和衰减响应的主要特征,其技巧主要来源于对于东部型El Nino影响的准确把握。总体来看,该模式对东亚夏季气候的预测能力较好,对短期气候预测具有一定参考价值。

Based on circulation and precipitation hindcast and real-time forecast data of BCC Second-Generation Climate System Model developed by National Climate Centre,the evaluation of the ability of the model for East Asian summer climate prediction is carried by using the synchronized and lag correlation,partial correlation and combined EOF decomposition analysis.The results show that the main spatial distribution of high-and low-level circulation and precipitation climatical fields can be well predicted,particularly the location of the heavy rainfall center and members of the monsoon system,but with some systematic biases.The model has poor performance in predicting the precipitation interannual variability in East Asia,especially in China,but has decent prediction ability for the interannual variability of 500 hPa geopotential height,and its skill improves with the approaching to the starting month.In addition,the model can predict the temporal and spatial distribution of the main modes of interannual variations of the East Asian climate with high skills.It can also catch the main characteristics of the response of East Asian climate variability to the developing El Nino and decaying El Nino period.This skill mainly comes from the accurate grasp of the east patern El Nino events.Overall,the BCC Second-Generation Climate System Model can predict the East Asian summer climate with decent skill,which can benefit the short-term climate prediction.