“…These findings have greatly improved our understanding of the role of the diurnal cycle in the tropical climate system. Among the existing studies, however, investigations of diurnal ocean variation are mainly for the western Pacific warm pool region [ Shinoda and Hendon , ; Bernie et al ., ; Shinoda , ] or the Atlantic Ocean [ Pimentel et al ., 2008; Guemas et al ., ], whereas coupled model studies focus primarily on the general effects of diurnal coupling on the mean structure and low‐frequency variability of the climate [ Danabasoglu et al ., ; Bernie et al ., ; Noh et al ., ; Oh et al ., ; Masson et al ., ; Guemas et al ., ]. In the present study, we examine the effects of diurnal cycle on the intraseasonal SST variability in the TIO region where many winter MJO events originate, which has not yet been sufficiently explored by previous researches.…”