IOD-Indian Ocean Dipole
IOD was in news because Indian Meteorological Department in its latest release in June 2014 predicted that El Nino will affect the Indian Monsoon with 70 percent probability. As a result in 2014, Indian Monsoon will be sub-normal.
Indian Ocean Dipole (IOD) is also known as Indian Nino. IOD is defined by the difference in sea surface temperature between two areas– a western pole in the Arabian Sea (western Indian Ocean) and an eastern pole in the eastern Indian Ocean south of Indonesia.
The IOD affects the climate of Australia and other countries that surround the Indian Ocean Basin, and is a significant contributor to rainfall variability in this region.
During a positive IOD, the eastern equatorial Indian Ocean off Sumatra in Indonesia becomes colder than normal while the western tropical part of the ocean near the African coast becomes unusually warm. Such an event has been found to be beneficial for the monsoon.
On the other hand, during a negative IOD the temperatures at eastern equatorial Indian Ocean becomes warmer while western Tropical Ocean become colder, which hampers the monsoon.