The Indian Meteorological Department (IMD) has stated that regular rainfall may be expected in India during the southwest monsoon season. This is because of the positive Indian Ocean Dipole (IOD), and the El Nino situation that would be mitigated by the lack of snow cover in the northern hemisphere. The Indian Ocean Dipole (IOD) and El Nino influence are usually the reason for the distribution of rainfall. If the IOD is positive, the El Nino impact will suffer.

However, according to a recent Skymet weather projection, India’s southwest monsoon in 2023 is expected to be below average. Skymet Weather is a private weather forecasting company headquartered in Noida, Uttar Pradesh. According to the bureau, there is a 70% likelihood of normal rainfall in June and a 50% chance of normal rainfall in July. This conflict in the report will only be evident with time.

What does the Indian Ocean Dipole IOD refer to?

The Indian Ocean Dipole, or IOD, is a climate phenomenon that occurs in the Indian Ocean. It is characterized by the difference in sea surface temperatures (SST) between two regions: the western Indian Ocean (near the eastern coast of Africa) and the eastern Indian Ocean (near Indonesia and Australia). The IOD is also known as the Indian Niño, referring to its similarity to the El Niño-Southern Oscillation (ENSO) phenomenon in the Pacific Ocean.

The IOD has three phases: positive, neutral, and negative.

Positive IOD

 During a positive IOD phase, the western Indian Ocean becomes cooler than average, while the eastern Indian Ocean experiences warmer-than-average temperatures. This temperature gradient creates a dipole pattern. The positive IOD phase is often associated with decreased rainfall in eastern Africa and increased rainfall in the maritime continent (Indonesia and surrounding areas). It can lead to droughts, crop failures, and forest fires in affected regions.

Neutral IOD

 In a neutral IOD phase, there is no significant temperature gradient between the western and eastern Indian oceans. This phase doesn’t have a strong impact on regional weather patterns.

Negative IOD

 During a negative IOD phase, the situation is reversed compared to a positive IOD. The western Indian Ocean experiences warmer-than-average temperatures, while the eastern Indian Ocean becomes cooler. This phase is associated with increased rainfall in eastern Africa and decreased rainfall in the maritime continent. It can lead to flooding in affected regions.

The Indian Ocean Dipole affects weather patterns and climate variability in surrounding regions, particularly in East Africa, the Indian subcontinent, and Southeast Asia. Various factors influence it, including sea surface temperatures, wind patterns, and ocean currents. Climate models and observations are used to monitor and predict the occurrence of the IOD, aiding in understanding its impacts and potential implications for agriculture, ecosystems, and regional weather patterns.

Impact of Normal Southwest Monsoon

The IMD forecasting is welcome news for the Indian agricultural industry, which is largely reliant on monsoon rains for crop output. Normal rainfall is expected in India during the southwest monsoon season, which runs from June to September. Rainfed agriculture is an important part of India’s agricultural environment, accounting for 52% of the net cultivated area. This practice accounts for over 40% of the total food output in India, making it an important contributor to food security and economic stability.

According to the Secretary of the Ministry of Earth Sciences, it is expected to rain by 96 percent with a 5 percent error margin of the long-period average of around 87 cm. The IMD further said that not all El Nino years result in a poor monsoon. El Nino conditions are most common during the monsoon season and have the most impact in the second half of the season. From 1951 to 2022, there were 15 ‘El Nino’ years. It is defined as a temperature rise of more than half a degree Celsius in the central, equatorial Pacific Ocean, with nine of those years experiencing ‘below average’ precipitation.

Also Read: El Nino in India: What Do The Forecasts Suggest?