What is the Indian Ocean Dipole?
The Indian Ocean Dipole is a climate pattern affecting the Indian Ocean. During a positive phase, warm waters are pushed to the Western part of the Indian Ocean, while cold deep waters are brought up to the surface in the Eastern Indian Ocean. This pattern is reversed during the negative phase of the IOD.
What are we looking at?
The plot tracks the conditions in the Indian Ocean, showing the phase of the IOD both now and in the past. When the value of the time series is positive (red shading), the warm phase of the IOD is present with higher sea level in the western Indian Ocean and lower sea level in the eastern Indian Ocean. When the value is negative (blue shading), the cool phase of the IOD is present with lower sea level in the western Indian Ocean and higher sea level in the eastern Indian Ocean.
Why do we care?
The IOD influences the local weather. During the positive phase of the IOD, the high temperatures along the coast of Africa cause heavy rains and droughts in Australia. During a negative phase the high temperatures and rainfall patterns are reversed. The sea-level changes associated with the IOD can also lead to increased threats of coastal flooding and associated impacts.
Reference: Kumar et al., 2020