New Delhi, Private weather forecasting agency Skymet has predicted a normal monsoon this year which is expected to finish around the normal range’s midway mark of 96 to 104 per cent of the long period average of 880.6mm.
The agency said it is in the process of gathering data sets pertinent for a comprehensive monsoon forecast and intends to release a detailed report in April.
“Ascertaining authenticity is absolutely essential and that is a long-drawn procedure. Therefore, it is a bit premature to share the collated figures but suffice to present preliminary guidance,” it said in a statement.
Monsoon has large inter-annual fluctuations in its arrival, intensity, duration, and withdrawal.
It is rather early to decode all these aspects at this stage. But there are precursors to get an early glimpse and gauge its health during the four-month-long season, Skymet said.
The last two monsoon seasons have been driven by back-to-back La Nina events which have started shrinking now, the agency said.
“It also means that monsoon 2022 is going to be a devolving La Nina to start with and turn neutral later. Negative sea surface temperature anomalies in the equatorial Pacific Ocean are weakening.
“This warming inclination of the Pacific Ocean, albeit within neutral limits, may not lead to an above-normal or excess rainfall but chances of a ‘corrupt’ monsoon are also ruled out,” it said. This could be one of the ‘normal’ monsoon years, making a robust start and finishing around the midway mark of the normal range — 96 per cent to 104 per cent of LPA (880.6mm),” it said.
G P Sharma, President, Meteorology and Climate Change, Skymet Weather, said, “After observing back-to-back La Nina during 2020 and 2021, the chances of yet another episode is statistically ruled out.” The sea surface temperatures in the equatorial Pacific are likely to rise soon and the probability of continued La Nina will fall. However, ENSO predictability decreases during the upcoming ‘spring barrier’ and at times leads to an unstable ENSO regime, he said.
This will get factored in our April forecast. While the monsoon trough is over the South Tropical Indian Ocean, Indian Ocean Dipole events are typically unable to form till April, Sharma noted.
“Reliable trends of ‘Indian Ocean Dipole’ emerge in the latter half of it. Early indications suggest it to be ‘neutral’ but leaning close to the negative threshold. IOD-ENSO interaction will hold the key to the overall health of Indian Summer Monsoon 2022,” he said. The El Nino-Southern Oscillation (ENSO) is an irregular cycle of change in wind and sea surface temperatures over the tropical eastern Pacific Ocean, affecting the climate of much of the tropics and subtropics.
The warming phase of the sea temperature is known as El Nino and the cooling phase as La Nina. El Nino has been generally known to suppress monsoon rainfall in India while La Nina increases it.
Indian Ocean Dipole, also known as Indian Nino, is an irregular oscillation of sea-surface temperature in which the Western Indian Ocean becomes alternately warmer and then colder than the eastern part of the ocean. IOD has three phases — neutral, negative and positive.
Positive IOD events are beneficial for the monsoon and negative IOD obstructs the progression of the monsoon over India.
In 2021, the country received “normal” rainfall during the four-month southwest monsoon season from June to September — 87 cm against the LPA of 88 cm of 1961-2010.
It was the third consecutive year that India recorded rainfall in the normal or above-normal category. PTI