Midwinter breakdown of ENSO climate impacts in East Asia

• Published in: npj Climate and Atmospheric Science
• Main Authors: Xin Geng, Kyung-Min Noh, Kyungna Kim, Jong-Seong Kug
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2023
• Subjects: Environmental sciences; GE1-350; Meteorology. Climatology; QC851-999; North Atlantic; North Atlantic oscillation
• Online Access: https://doi.org/10.1038/s41612-023-00474-4; https://doaj.org/article/204d4b9ed32b4646baa131a8e96e815a

Abstract The El Niño-Southern Oscillation (ENSO) influence on the East Asian winter monsoon (EAWM) exhibits remarkable non-stationarity on subseasonal timescales, severely limiting climate predictability. Here, based on observational and reanalysis datasets, we identify a robust subseasonal variability in the EAWM response to ENSO, with a notable synchronous break in mid-January lasting about 10 days. We suggest that this breakdown is largely caused by interference from the abrupt phase reversal of the ENSO-driven North Atlantic Oscillation (NAO), which occurs about a week earlier in early January. During El Niño years, the NAO phase transition from positive to negative triggers a rapid change in the mid-latitude atmospheric circulation via the quasi-stationary Rossby wave adjustment. This results in the strengthening of the Siberian high, which produces strong northerly wind anomalies over East Asia, while the anomalous western North Pacific anticyclone weakens and shrinks to the south, eventually leading to the collapse of the teleconnection.