Fig. 3: Roles of AM in JJA in generating IOT events.

a Correlation coefficients between IOT in JAS and SST/850hPa wind anomalies in JAS. b Correlation coefficients between the AM index in JJA and SST/850hPa wind anomalies in JAS. c Same as (b), but showing partial correlation with AM index by removing variability associated with the Niño3.4 index. d Same as b, but for latent heat flux anomalies, e Same as b, but for precipitation anomalies. f Same as (b), but for SSH anomalies. Purple boxes delineate the region used to define the AM index, while green and red boxes are employed to establish the IOT index. Dotted areas indicate significance above the 95% confidence level (Student’s t test). All correlations in (b–f) are multiplied by −1.