Abstract
AbstractA record-breaking Meiyu-Baiu rainfall hit East Asia in June–July 2020. The warm Indian Ocean (IO) has been identified as a primary cause, but it cannot explain the heavy rainfall in July, a striking characteristic of the 2020 Meiyu-Baiu rainfall. A remarkable retreat of Arctic sea ice in the late spring and early summer of 2020 also promoted Meiyu-Baiu rainfall by favoring North Asian blockings and cold air outbreaks. However, its importance compared with IO warming is unclear. Our result shows that the abundant moisture supply to the 2020 Meiyu-Baiu rainfall mainly stems from anomalous meridional wind convergence, while the excessive ascending motions are due to warm advection tied to enhanced mid-troposphere westerlies. AGCM experiments are used to examine the relative importance of IO warming and Arctic sea ice anomalies. In June, IO warming is responsible for the atmospheric circulation anomalies around the Meiyu-Baiu region and accounts for ~ 75% of the Meiyu-Baiu rainfall anomalies, despite the Arctic sea-ice loss explaining most circulation anomalies over Eurasian high latitudes. In July, both IO warming and Arctic sea-ice loss are necessary for meridional convergence, enhanced westerlies, and thus the heavy rainfall over the Meiyu-Baiu region. Their effects are interdependent rather than additive. Strong IO warming is rarely observed alongside severe Arctic sea-ice loss before 2020 because of their discordant interannual variations. In the future, the combined effects of IO warming and Arctic sea-ice loss on the Meiyu-Baiu rainfall may become more pronounced as their long-term trends continue.
Funder
National Natural Science Foundation of China
Postdoctoral Research Foundation of China
Postdoctoral Science Foundation of China
Publisher
Springer Science and Business Media LLC
Reference60 articles.
1. Ashok K, Behera SK, Rao SA, Weng H, Yamagata T (2007) El Niño Modoki and its possible teleconnection. J Geophys Res 112:C11007. https://doi.org/10.1029/2006JC003798
2. Chen Y, Zhai P (2014) Precursor circulation features for persistent extreme precipitation in Central-Eastern China. Weather Forecast 29:226–240. https://doi.org/10.1175/WAF-D-13-00065.1
3. Chen T, Zhang FH, Yu C, Ma J, Zhang XD, Shen XL, Zhang F, Luo Q (2020) Synoptic analysis of extreme Meiyu precipitation over Yangtze River Basin during June–July 2020. Meteor Mon 46:1415–1426 ((in chinese))
4. Chen X, Dai A, Wen Z, Song Y (2021) Contributions of Arctic sea-ice loss and East Siberian atmospheric blocking to 2020 record-breaking Meiyu-Baiu rainfall. Geophys Res Lett 48:e2021GL092748. https://doi.org/10.1029/2021GL092748
5. Chowdary JS, Xie SP, Luo J, Hafner J, Behera S, Masumoto Y, Yamagata T (2011) Predictability of Northwest Pacific climate during summer and the role of the tropical Indian Ocean. Clim Dyn 36:607–621. https://doi.org/10.1007/s00382-009-0686-5
Cited by
14 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献