Influence of Ningaloo Niño/Niña Events on Autumn Rain Anomalies in West China

Based on monthly sea surface temperature (SST) data from 1979 to 2016 provided by NOAA alongside NCEP/NCAR reanalysis data and CN05.1 precipitation data, the relationship between Ningaloo Niño/Niña events and the autumn rainfall anomalies across West China was investigated. The results indicate obvious changes in SST in the East subtropical Indian Ocean during the autumn of Ningaloo Niño/Niña years. After deducting the influence of El Niño–Southern Oscillation (ENSO), a positive correlation emerges, linking Ningaloo Niño events with autumn rain in West China. During Ningaloo Niño (or Niña) years, sea temperatures around western Australia increase in autumn, resulting in enhanced abnormal meridional circulation that increases the updraft (or downdraft) in West China. This is accompanied by an enhanced (or weakened) convergence of water vapor from the South China Sea toward West China. The zonal circulation anomalies near the equator are closely related to the meridional circulation anomalies extending from low to mid-high latitudes in the Northern Hemisphere. Consequently, the longitudinal extent of circulation across the middle and high latitudes of Eurasia increases (or decreases), creating conducive conditions for increasing (or decreasing) autumn rain in West China and providing a new approach for forecasting this rainfall.