Indian Ocean Dipole

The IOD is one aspect of the general cycle of global climate, interacting with similar phenomena like the El Niño-Southern Oscillation (ENSO) in the Pacific Ocean.

[12] A 2009 study by Ummenhofer et al. at the University of New South Wales (UNSW) Climate Change Research Centre has demonstrated a significant correlation between the IOD and drought in the southern half of Australia, in particular the south-east.

In the IOD-positive phase, the pattern of ocean temperatures is reversed, weakening the winds and reducing the amount of moisture picked up and transported across Australia.

[14][15][16] A positive IOD is linked to higher than average rainfall during the East African Short Rains (EASR) between October and December.

[18] This higher than average rainfall has resulted in a high prevalence of flooding in the countries of Djibouti, Ethiopia, Kenya, Uganda, Tanzania, Somalia and South Sudan.

[20][21][22][23] It is expected that the Western Indian ocean will warm at accelerated rates due to climate change[24][25] leading to an increasing occurrence of positive IODs.

[27] A 2018 study by Hameed et al. at the University of Aizu simulated the impact of a positive IOD event on Pacific surface wind and SST variations.

Water temperatures around the Mentawai Islands dropped about 4 °C during the height of a positive phase of the Indian Ocean Dipole in November 1997. During these events unusually strong winds from the east push warm surface water towards Africa, allowing cold water to upwell along the Sumatran coast. In this image blue areas are cooler than normal, while red areas are warmer than normal.