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Enhanced Meiyu‐Baiu Rainfall in Early Summer 2020: Aftermath of the 2019 Super IOD Event
Author(s) -
Takaya Yuhei,
Ishikawa Ichiro,
Kobayashi Chiaki,
Endo Hirokazu,
Ose Tomoaki
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090671
Subject(s) - climatology , indian ocean dipole , rossby wave , environmental science , predictability , monsoon , teleconnection , geology , sea surface temperature , oceanography , el niño southern oscillation , physics , quantum mechanics
Abstract In early summer 2020, the Meiyu‐Baiu rainfall was markedly enhanced, triggering devastating floods in Japan and central China. We examined the underlying processes using a climate model and analysis. The enhanced Meiyu‐Baiu rainfall was reasonably predicted by the climate model initialized at the end of April. The sensitivity experiment indicated that Indian Ocean (IO) warming enhanced the Meiyu‐Baiu rainfall. Moreover, we found that the warm IO condition can be traced back to the super Indian Ocean Dipole (IOD) in 2019. The IO warmth was influenced by successive processes: record strong downwelling Rossby waves excited by the IOD and tripole sea surface temperature anomalies in the tropical IO‐western Pacific, their arrival to the southwestern IO in spring, and associated modulation of monsoon flow. The results suggest that the seasonal predictability of the Meiyu‐Baiu rainfall in 2020 originated from the super IOD.