Indian Ocean Dipole: What is it and how can it cause higher rainfall in the country?

The Indian Monsoon is here, but the El Nino phenomenon is playing dampener. Experts have said that the El Nino phenomenon will impact the rains in the country, which may lead to destroyed crops and force authorities to limit the export of some food grains. In fact, Dr Akshay Deoras, research scientist at the National Centre for Atmospheric Science, department of meteorology, University of Reading, UK, had told Deccan Chronicle earlier, “It will definitely be impacting the monsoon. This is not something that is going to happen in the future. It is already happening.” However, there’s a glimmer of hope that El Nino won’t be a complete monsoon killer owing to the possibility of the development of a positive Indian Ocean Dipole, which will counterbalance the El Nino effect. But what is a positive Indian Ocean Dipole? How will it help the Indian monsoon? Why is this significant for India? Here’s what we know. Indian Ocean Dipole: What is it? Also known as the Indian Nino, the Indian Ocean Dipole (IOD) is defined as the difference in sea surface temperature between the western pole of the Arabian Sea (western Indian Ocean) and an eastern pole south of Indonesia, which has an impact on the climate of Australia and other nations in the Indian Ocean Basin. Experts state that the IOD is similar to the El Nino phenomenon but that it plays out in the relatively smaller area of the Indian Ocean between the Indonesian and Malaysian coastline in the east and the African coastline near Somalia in the west. It primarily sees one side of the ocean, along the equator, getting warmer than the other. The IOD is said to be positive when the western side of the Indian Ocean, near the Somalia coast, becomes warmer than the eastern Indian Ocean. It’s said to be negative when the western Indian Ocean is cooler. According to an Indian Express report, a positive IOD event is often seen developing at times of an El Nino, while a negative IOD is sometimes associated with La Nina. Many studies suggest that IOD events are actually induced by El Nino Southern Oscillation (ENSO). But Professor Ashok Karumuri, a senior scientist at the King Abdullah University of Science and Technology in Saudi Arabia, has said there is evidence to show that IOD events can have an independent existence. What impact will IOD have? Depending on the phase of the IOD, it has different impacts on the weather of a region. As of now, the Indian Ocean Dipole seems to be in a neutral phase. Australia’s Bureau of Meteorology in its newest update stated, “The Indian Ocean Dipole is currently neutral. All international climate models surveyed by the Bureau suggest a positive IOD event may develop in the coming months.” “During a positive IOD event, the western Indian Ocean experiences higher-than-normal rainfall, while the eastern Indian Ocean experiences drier-than-normal conditions. This can lead to increased rainfall over India and can offset the effects of El Nino, which usually brings drier-than-normal conditions to India,” explained Dr Anjal Prakash, research director, Bharti Institute of Public Policy, Indian School of Business and Intergovernmental Panel on Climate Change author to ABPLive. [caption id=“attachment_12800262” align=“alignnone” width=“640”] Graphic: Pranay Bhardwaj[/caption] Dr Andrew Turner, a lecturer in monsoon systems at the UK’s University of Reading, echoed similar thoughts to the BBC. He said, “When an Indian Ocean dipole event occurs, the rainfall tends to move with the warm waters, so you get more rainfall than normal over the East African countries.” In 2019, it was a positive Indian Ocean Dipole that had caused floods in East Africa, with the Horn of Africa seeing up to 300 per cent above average rainfall between October and mid-November. Similarly, the devastating bushfires in Australia in 2020 was owing to an extreme Indian Ocean Dipole. [caption id=“attachment_12800322” align=“alignnone” width=“640”] A family enjoys a rainy day as the southwest Monsoon advances over Delhi, at Kartavya Path on Sunday. PTI[/caption] What about El Nino? If the predictions of a development of a positive IOD come true – they normally originate in the months of April and May – they would counterbalance the effects of El Nino in India. But how does El Nino affect the Indian monsoon? For the unaware, El Nino is a weather phenomenon that occurs when ocean temperatures in the central and eastern Pacific Ocean rise above normal. The warming causes changes in atmospheric patterns, leading to a weakening of the monsoon circulation over the Indian subcontinent. As a result, the Indian monsoon tends to be weaker and less reliable during El Nino years. Weather experts note that over the past seven decades, the El Nino weather pattern occurred has 15 times and of these nine monsoon seasons have experienced deficient rainfall . In the last four El Nino years, India has constantly faced drought conditions and a severe decrease in rainfall. **Also read: Monsoon Mayhem: THESE Indian states are experiencing severe rains** El Nino’s impact on the monsoon also affects India’s agricultural sector. This is because the country’s monsoon (the season between June and September) provides about 70 per cent of annual rain and impacts key crops such as rice, wheat, sugarcane, soybeans, and peanuts. Agriculture contributes about 19 per cent to India’s $3 trillion economy and employs more than half of the 1.4 billion population, reported Reuters. Rating agency Icra had in its May report said, “If El Nino materialises and affects the Indian monsoon in FY24, it will have an impact on multiple sectors, apart from agriculture and may lead to a downward revision of growth estimates, profitability, and also deterioration of leverage ratios and higher import dependency.” Here’s hoping that a positive IOD develops and India receives sufficient rainfall. Not just to avoid burning a hole in our pockets while buying vegetables but also for the overall growth of our country. With inputs from agencies Read all the Latest News , Trending News , Cricket News , Bollywood News , India News and Entertainment News here. Follow us on Facebook, Twitter and Instagram.