Impact of the Indian Ocean SST basin mode on the Asian summer monsoon

Following an El Niño event, a basin‐wide warming takes place over the tropical Indian Ocean, peaks in late boreal winter and early spring, and persists through boreal summer. Our observational analysis suggests that this Indian Ocean warming induces robust climatic anomalies in the summer Indo‐West Pacific region, prolonging the El Niño's influence after tropical East Pacific sea surface temperature has returned to normal. In response to the Indian Ocean warming, precipitation increases over most of the basin, forcing a Matsuno‐Gill pattern in the upper troposphere with a strengthened South Asian high. Near the ground, the southwest monsoon intensifies over the Arabian Sea and weakens over the South China and…