Open AccessDistinct East Asian precipitation variability and predictability in coupled and uncoupled El Niño events
Author(s) -
Yunyun Liu,
Renguang Wu,
Yihui Ding
Publication year - 2021
Publication title -
environmental research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.37
H-Index - 124
ISSN - 1748-9326
DOI - 10.1088/1748-9326/ac19de
Subject(s) - anticyclone , predictability , precipitation , climatology , sea surface temperature , east asia , environmental science , flux (metallurgy) , geology , atmospheric sciences , geography , materials science , china , physics , meteorology , archaeology , quantum mechanics , metallurgy
Previous studies have shown different impacts of eastern (EP) and central (CP) Pacific El Niños on the East Asian precipitation. This study reveals distinct precipitation anomalies over East Asia in coupled and uncoupled El Niños. The uncoupled warm events in 1979, 2004, 2014, 2018, and 2019, which occurred in the autumn–winter transition, represent an unusual form of El Niño diversity. The sea surface temperature anomalies (SSTA) in the western North Pacific (WNP) appear to be an important factor leading to the different distribution of precipitation anomalies over East Asia and the WNP. In coupled El Niños, anomalous lower-level anticyclone over the WNP is a result of combined effects of warm SSTAs in the equatorial CP and EP and cold SSTAs in the WNP. The cold SSTAs are attributed to surface heat flux anomalies that in turn are associated with convection and wind anomalies. The lack of cold SSTAs in the WNP in the uncoupled El Niños leads to a weaker anomalous anticyclone with a northwestward location. The different features of an anomalous anticyclone over the WNP induce discrepancy in the distribution of precipitation anomalies and the associated predictability over East Asia between coupled and uncoupled El Niños. The prediction skill tends to be lower for the uncoupled El Niño events than the coupled ones, which further indicates the necessity to distinguish uncoupled from coupled warm events.