大样本初始化十年际预测试验(CESM-DPLE)对东亚夏季气候预测的评估

Evaluation of summer climate prediction over East Asia by Large Ensemble CESM Initialized Decadal Prediction(CESM-DPLE) Project

  • 摘要: 基于气温和降水观测资料以及美国国家环境预报中心/国家大气研究中心(NCEP/NCAR)大气再分析资料,系统评估了大样本初始化十年际预测试验(CESM-DPLE)对1959—2016年东亚夏季气候预测的能力。结果表明,CESM-DPLE能较好地模拟东亚夏季气候以及相关主要大气环流系统的基本态特征,在年际尺度上对东亚气温有很高的预测技巧但对降水几乎没有预测能力。CESM-DPLE再现了北大西洋多年代际振荡(AMO)经由激发遥相关波列所引起的中高纬度大气环流、东亚夏季风和气候的异常。20世纪90年代末之后,北大西洋多年代际振荡由冷位相转为暖位相,遥相关波列位相调整,东亚受异常低压控制,东亚夏季风偏强,夏季气温偏高、降水偏多。总体上,尽管还存在着不足,但CESM-DPLE对东亚夏季温度年际变化以及与20世纪90年代末北大西洋多年代际振荡位相转变相联的东亚夏季气候年代际变化具备一定的预测能力,是目前研究和预测东亚气候变化的一套较好试验数据。

     

    Abstract: Based on observations of surface air temperature and precipitation and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) atmospheric reanalysis data, the prediction of East Asian summer climate during 1959—2016 conducted by the Large Ensemble CESM (Community Earth System Model) Initialized Decadal Prediction (CESM-DPLE) Project is evaluated in this study. The results show that the CESM-DPLE can reasonably capture the basic East Asian summer climate features and associated main atmospheric circulation patterns. In general, the prediction skill is high for surface air temperature but the CESM-DPLE shows almost no skill for precipitation prediction on interannual time scale. The CESM-DPLE can well reproduce the anomalies of mid- and high-latitude atmospheric circulations and the East Asian monsoon and climate caused by the teleconnection wave trains driven by the Atlantic Multidecadal Oscillation (AMO). After the AMO transition into the warm phase since the late 1990s, geopotential height decreased and monsoon in East Asia enhanced via teleconnection wave train during summer, leading to excessive precipitation and warming over East Asia. Overall, the CESM-DPLE to a certain degree is capable of predicting the East Asian summer temperature on the interannual time scale and the interdecadal variations of East Asian summer climate associated with the transition of the AMO phase in the late 1990s, although there still exist some inadequacies. The CESM-DPLE Project provides an important resource for investigating and predicting the East Asian climate on the interannual and decadal time scales.

     

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