Diverse impacts of strong and moderate intense El Niño–Southern Oscillation events on spring precipitation over Asia

Abstract

AbstractEl Niño–Southern Oscillation (ENSO) events are a major predictor of Asian spring precipitation. However, it is unclear whether ENSO events with different intensities have similar or different impacts on Asian spring precipitation. This question is explored in this study. According to their intensity, ENSO events are divided into strong and moderate (S‐ENSO and M‐ENSO) events. The analysis indicates that S‐ENSO events have stronger sea surface temperature (SST) anomalies over the tropical Pacific and Indian oceans, and warm/cold events can lead to significantly more/less precipitation over Central Asia and East China as well as less/more precipitation over the Indo‐China Peninsula, Tibetan Plateau, and Maritime Continent. The S‐ENSO events significantly affect the Walker circulation and West Pacific anticyclone and excite an eastward‐propagating wave train over the midlatitude Northern Hemisphere. The changes in these atmospheric circulations further alter the dynamic and moisture conditions over the aforementioned Asian regions, consequently leading to precipitation anomalies. In contrast, the M‐ENSO events have relatively weak SST anomalies over the tropics, and the warm/cold events can result in more/less precipitation over Central Asia, Mongolia and northern China and less/more precipitation over northeastern Siberia, South China and the Maritime Continent. The impact of M‐ENSO events on spring precipitation over the Asian regions mainly occurs due to modulating effects on the western Pacific pattern, Aleutian Low, and anomalous anticyclones over northwestern Asia. The results in this study indicate that ENSO events of different intensities may have different impacts on Asian spring precipitation, which should be considered when predicting it.