Effects of AO on the interdecadal oscillating relationship between the ENSO and East Asian winter monsoon

• Published in: International Journal of Climatology
• Main Authors: Chen, Dong, Sun, Jianqi, Gao, Ya
• Other Authors: National Natural Science Foundation of China
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2020
• Subjects: Arctic; Pacific
• Online Access: http://dx.doi.org/10.1002/joc.6459; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fjoc.6459; https://onlinelibrary.wiley.com/doi/pdf/10.1002/joc.6459; https://onlinelibrary.wiley.com/doi/full-xml/10.1002/joc.6459; https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/joc.6459

Abstract Based on the Twentieth Century Reanalysis version 2 datasets (1871–2010), this article first analyzes the relationships of the Arctic Oscillation (AO) and the El Niño‐Southern Oscillation (ENSO) with the East Asian winter monsoon (EAWM) and further investigates the changes in the relationships between the ENSO (AO) and EAWM before and after removing the AO (ENSO) signal. As revealed by previous studies, an interdecadal oscillating relationship is found between the ENSO and EAWM. This oscillation disappears when the AO signal is removed; however, the ENSO–EAWM relationship has exhibited a stable and significant negative correlation over the past 140 years. In contrast, the oscillating relationship (with a period of approximately 60 years) between the AO and EAWM shows little differences when the ENSO signal is removed. Further analysis reveals the main reasons for the strengthening of the ENSO–EAWM relationship by removing the AO signal. The results show that after removing the AO signal, the ENSO‐induced anomalous sinking branch of the Walker circulation over the western Pacific shifts northwestward, and the ENSO‐related anomalous anticyclone in the northern part of the western Pacific strengthens. Such circulation anomalies are conducive to the establishment of the East Asia–North Pacific teleconnection, which is favourable for the ENSO–EAWM relationship. The above results reveal that there is an interdecadal oscillation in the AO–EAWM relationship and the ENSO–EAWM relationship may be relatively stable, the interdecadal oscillation only occurs under the influence of the AO. These results may improve the use of ENSO for predicting the EAWM on seasonal time scale in the future.