The most characteristic feature of Indian Ocean climate is Monsoon, which has large seasonal changes in wind and rainfall. The anomalies are often associated with strong intraseasonal disturbances that can determine the character of an entire season of rainfall. However understanding of oceanic response of these atmospheric forcing and feedback mechanism is insufficient because of scarce observations.

One of the major interannual variations in the Indian Ocean is Indian Ocean dipole mode, which is a coupled ocean-atmosphere phenomenon. A canonical Indian Ocean dipole event has negative sea surface temperature anomaly in the southeastern tropical region, with easterly wind anomaly in the equator. The negative sea surface anomaly in the southeastern tropical region is intensified through a positive feedback mechanism during the event. Anomalous sea surface temperature pattern produces migration of atmospheric convection cells, and affects regional and global climate systems via atmospheric teleconnections.

Understanding of these key phenomena of regional and global climate systems sustained, in situ observations are requested.