Upper Ocean Temperature Variability Associated With the Indian Ocean Dipole Revealed by a Complex Network

A new framework of complex networks based on event synchronization that can be applied to the development of temperature anomalies associated with climate variation phenomena is developed to reveal propagation characteristics of ocean temperature anomalies and their asymmetry between positive and negative phases of the Indian Ocean Dipole (IOD). When a complex network based on sea surface temperature (SST) is constructed, it is revealed that SST anomalies in the eastern pole associated with both phases of the IOD tend to be preceded by those in the eastern equatorial region and from the south. When a complex network is constructed based on both surface and subsurface temperatures, it is found that the positive IOD tends to experience extreme subsurface temperature anomalies over more vast areas before extreme SST anomalies compared to the negative IOD.