Biases and improvements of the ENSO-East Asian winter monsoon teleconnection in CMIP5 and CMIP6 models
Biases and improvements of the ENSO-East Asian winter monsoon teleconnection in CMIP5 and CMIP6 models
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DOI：
10.1007/s00382-022-06220-5
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发表时间：
2021-08
期刊：
影响因子：
4.6
通讯作者：
Wenping Jiang;H. Gong;Ping Huang;Lin Wang;G. Huang;Lisuo Hu
中科院分区：
文献类型：
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作者：
Wenping Jiang;H. Gong;Ping Huang;Lin Wang;G. Huang;Lisuo Hu
基于耦合模式比对项目（CMIP6）模型第6阶段的输出，研究了厄尔尼诺-南方涛动（ENSO）对东亚冬季风（EAWM）的影响，并与第5阶段（CMIP5）的结果进行了比较。结果表明，总体而言，CMIP6 模型比 CMIP5 模型更真实地再现了 ENSO-EAWM 遥相关，尽管它们仍然比观察到的稍微低估了 ENSO-EAWM 遥相关。基于CMIP5/CMIP6模式模拟的ENSO-EAWM遥相关的模式间传播，我们发现模式间普遍被低估的ENSO-EAWM遥相关可以追溯到冷舌向赤道西太平洋的过度延伸。具有更强气候冷舌的模型有利于产生与ENSO相关的海温异常模式更向西的延伸，这反过来又迫使西北太平洋（NWP）出现异常气旋环流。它抵消了 NWP 中的反气旋异常并削弱了 ENSO-EAWM 遥相关。与CMIP5模型相比，大多数CMIP6模型更好地模拟了SST平均状态和由此产生的ENSO-EAWM遥相关。目前的结果表明，为了进一步改进东亚-西太平洋冬季气候的模拟和预测，应大力减少平均状态海温的偏差。
The influence of El Niño–Southern Oscillation (ENSO) on the East Asian winter monsoon (EAWM) is investigated based on the outputs of phase 6 of the Coupled Model Intercomparison Project (CMIP6) models and compared to that in phase 5 (CMIP5). Results show that overall the CMIP6 models reproduce the ENSO-EAWM teleconnection more realistically than the CMIP5 models, although they still somewhat underestimate the ENSO-EAWM teleconnection than observed. Based on the intermodel spread of ENSO-EAWM teleconnection simulated in the CMIP5/CMIP6 models, we reveal that the commonly underestimated ENSO-EAWM teleconnection among the models can be traced back to the excessive extension of the cold tongue to the equatorial western Pacific. A model with a stronger climatological cold tongue favors generating a more westward extension of the ENSO-related SST anomaly pattern, which in turn forces an anomalous cyclonic circulation over the Northwest Pacific (NWP). It offsets the anticyclonic anomalies in the NWP and weakens the ENSO-EAWM teleconnection. Compared with the CMIP5 models, most CMIP6 models better simulate SST mean state and the resultant ENSO-EAWM teleconnection. The present results suggest that substantial efforts should be made to reduce the bias in the mean-state SST for further improving the simulation and projection of the East Asian-western Pacific winter climate.