1. What is the Indian Ocean Dipole (IOD)?
The Indian Ocean Dipole (IOD) refers to the swing in sea-surface temperatures from warm to cool in the Indian Ocean basin to the south of Sri Lanka.
2. What does a positive IOD event indicate?
A positive IOD event occurs when sea-surface temperatures are warmer in the western side of the Indian Ocean basin. It can impact weather patterns and has been associated with boosting the performance of India's South-West monsoon.
3. How is the IOD index measured?
The IOD index quantifies the deviation of sea-surface temperatures from the norm. It is expressed in degrees Celsius (°C) and helps determine the intensity of the IOD event.
4. What is the significance of the positive IOD threshold?
The positive IOD threshold, usually around +0.4°C, indicates the minimum deviation from the norm that must be met for an IOD event to be considered positive.
5. How does a positive IOD event affect the monsoon in India?
Positive IOD events can enhance the performance of India's South-West monsoon, leading to increased rainfall in certain regions.
6. What are the predictions for the IOD event in 2023?
The Australian Bureau of Meteorology predicts a potential IOD event in 2023, which might be briefer than the strong 2019 event. Some climate models indicate a relatively strong event.
7. How does the strength of the 2023 IOD event compare to the 2019 event?
The 2019 IOD event was one of the strongest on record, with peak index values close to +2.0°C. In contrast, forecasts suggest a peak value of around 1.5°C for the 2023 event.
8. What impact does the IOD have on rainfall in other regions?
The IOD can affect rainfall patterns in various regions, such as Sri Lanka, parts of Kerala and Tamil Nadu, Nepal, Bhutan, East Asia, Central and West Africa, and more. Some regions might experience wetter-than-normal conditions during a positive IOD event.
9. How does the IOD interact with other climate phenomena?
In Australia, a positive IOD event can lead to low rainfall, a late monsoon onset, and low tropical cyclone activity from October to December. If combined with El Nino, the impacts can be more severe and extend further into the wet season.
10. What are the implications of a positive IOD event for different regions?
Positive IOD events can bring varied impacts to different regions, affecting monsoon patterns, rainfall distribution, and even cyclone activity, depending on the interaction with other climate factors.
