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Key things to know about IOD
- The IOD changes between positive, neutral and negative phases.
- When warmer surface waters are closer to Australia (IOD negative), more moisture becomes available for rainfall.
- This moisture can travel towards Victoria through stronger winds and large north-west cloud bands.
- When moisture arrives in Victoria, and connects with cold fronts, higher rainfall can occur.
- Positive and neutral IOD events have been linked with drought in Australia.
This occurs when the Indian Ocean is warmer in the west (near the coast of Kenya) than it is in the east (near Sumatra). This reduces tropical moisture availability for Victoria, and can make for a drier spring.
When the Indian Ocean is warmer in the east than it is in the west we have an IOD negative event. This means that more moisture is available closer to Australia, and can be delivered to Victoria through northwest cloud bands. Typically IOD negative events have been associated with wetter seasons in Victoria.
Where to go for more information
For more information about the IOD visit some of the pages below.
- Read more about how the Indian Ocean impacts on Australian weather and climate.
- More information about the Indy on the Bureau of Meteorology website.
- Read a fact sheet from the South East Australian Climate Initiative about how the region's climate is changing, including research into how Indy influences our climate.