DIPOLE MODE INDEX
Intensity of the IOD is represented by anomalous SST gradient between the western equatorial Indian Ocean (50oE-70oE and 10oS-10oN) and the south eastern equatorial Indian Ocean (90oE-110oE and 10oS-0oN). This gradient is named as Dipole Mode Index (DMI). When the DMI is positive then, the phenomenon is refereed as the positive IOD and when it is negative, it is refereed as negative IOD. This dataset can be downloaded in a netcdf format here. Since, IOD is a coupled ocean-atmosphere phenomenon it can also be represented by any other atmospheric (pressure, olr) or oceanographic (sea surface height) as well. DMI derived from OLR anomalies can be downloaded from here.