Eastward Propagation of Anomalous Indo–Pacific Walker Circulation During ENSO Transition

Abstract By analyzing the zonal mass streamfunction over the equatorial Indo–Pacific region in the period 1979–2024, we found that during the decaying phase of 13 out of 31 El Niño‐Southern Oscillation (ENSO) events, the anomalous Indo–Pacific Walker Circulation (IPWC) propagates steadily eastward across the warm pool. Vertical velocity, precipitation, and energy transport over the warm pool exhibit similar eastward‐propagating features. Although strong sea surface temperature (SST) anomalies in the warm pool favor the eastward propagation of the anomalous IPWC during certain El Niño events, as indicated in previous studies, we demonstrate that the decaying rate of ENSO and changes in SST anomalies near the Maritime Continent may collectively drive this propagation. Our results suggest that the anomalous IPWC facilitates precipitation and energy transport between the tropical Indian Ocean and the Pacific.