Experts Slam ‘Hasty’ Declaration of Monsoon Onset Over Kerala by IMD
India may be staring at a delayed and dry southwestern monsoon in the first two months with a lot of heatwaves.
The onset of the southwest monsoon was declared on 29 May by the India Meteorological Department (IMD), but people of Kerala were left disappointed looking at the skies.
So, is the monsoon here? Well, the IMD declared that it has arrived, but its own criteria for declaring the onset of the monsoon says otherwise.
Experts slammed the IMD’s announcement as “premature” and also alleged this could affect future studies on rainfall patterns and climate change.
Southwest monsoon normally sets in over Kerala around 1 June. It advances northwards, usually in surges, and covers the entire country by around 15 July.
The Flip-Flop Show
This year several dates were thrown around -- there was a flip, then a flop, then a flip again.
On 12 May, the IMD predicted the "advance of the Southwest Monsoon into the south Andaman Sea and adjoining southeast Bay of Bengal around 15 May 2022." On 19 May, the IMD said that the onset over Kerala was possible by 25 May.
Then, private forecaster Skymet Weather predicted that it would unfold on 26 May, with a model error of +/-3 days. However, GP Sharma, President, Meteorology and Climate at Skymet Weather later said the country missed the bus regarding the early onset of the monsoon.
It is to be noted that over the last 50 years, the date of onset in Kerala has ranged from 19 May 1990 to 18 June 1972. This variance is largely attributed to the state of the ENSO – El Niño–Southern Oscillation – in the preceding winter. In the last 3 years, the monsoon arrived on 08 June, 01 June and 03 June in 2019, 2020 and 2021 respectively.
Did IMD ‘Blatantly’ Disregard Guidelines Set by Itself?
The IMD on 30 May clarified that its predictions about monsoon onset over Kerala were conditional, subject to the fulfilment of certain meteorological conditions.
IMD in a statement on Sunday said the depth and strength of westerly winds had increased; that cloudiness over southeast Arabian Sea and adjoining areas of Kerala had improved meeting the outgoing long wave radiation (OLR) criterion; and that there has been widespread rainfall activity over Kerala during the previous 24 hours and that 10 out of 24 rainfall monitoring stations received rainfall of 2.5 mm or more.
On Sunday, this criteria was not met. Rainfall was reported at a few places in Kottayam, Kollam, Alappuzha, Wayanad and Ernakulam districts on Monday, according to IMD.
Skymet argued that this was a "hasty" declaration and that onset criteria was "blatantly set aside." While winds and OLR was aligned for two days, the most important and visible manifestation of rainfall fell short on 28 and 30 May.
On 30 May, seven out of the 14 earmarked stations recorded NIL rainfall and two more locations registered less than 1mm.
“Declaring monsoon based on single day observations amounts to gross violation of standards, never attempted in the past. Any repute scientific body can ill afford to bend rules and criteria, just to prove the forecast right. Such a step, if taken knowingly, becomes highly objectionable and if otherwise, amounts to illusion of knowledge,” read the note by Skymet Weather.
“There is objective criteria that needs to be met and sanctity has to be maintained. What is IMD trying to prove? Will anyone punish them if the monsoon comes a few days late? There is no harm in admitting they are wrong because this is after all, a prediction.”GP Sharma, President, Meteorology and Climate at Skymet Weather to The Quint
24 Hr Rainfall (mm) – Monsoon Stations
Skymet’s claims were supported by a few other independent weather forecasters on social media who questioned IMD’s declaration.
Raj Bhagat P, an earth observer and a specialist in Geo Analytics told The Quint, "IMD has sent certain criteria for onset but they have not adhered to it themselves."
Declaring Monsoon Onset Wrong Could Lead To Confusing Messaging to Farmers
The monsoon season is crucial for summer crops and brings about 70% of India’s annual rainfall. Monsoon rains are a lifeline for about 60% of the country’s net cultivated area that has no irrigation.
The monsoon impacts inflation, jobs, and industrial demand. Ample harvests raise rural incomes and keeps a check on inflation.
Sharma explained that it is time a scientific body like IMD doesn’t play with the psychology of farmers who anticipate the onset of monsoon.
“The significance of the onset of monsoon is that it boosts the morale of the farmers. A few years ago, a bad forecast will not be declared at the beginning of the season, because they didn’t want to disappoint people. But with improvement in technology, it is alright to declare that it is a bad monsoon. 2014 and 2015 were drought years but India managed to absorb the shock and get over it. There is no need to unnecessarily lie about the forecast,” he told The Quint.
Based on the current projections, south Maharashtra, Madhya Maharashtra, Telangana, Andhra Pradesh, Karnataka, Kerala and Tamil Nadu will anticipate good rains around 10 June. Experts stated that declaring early monsoon onset could lead to confusing messaging to farmers, who could even incur huge losses.
Bhagat suggested that rather than using fixed thresholds for declaring monsoon onsets, IMD must consider using monsoon indices that talk about strength and phase which will help understand the rainfall patterns better.
“This seems like an unnecessary declaration as the exact onset date doesn't really matter. They need to start defining how strong or weak the monsoon is, which side it is traveling based on parameters but without any fixed thresholds,” he suggested.
He also pointed out that wrong declaration “could affect future reliance on onset data for studies related to climate change.”
This year, India may be staring at a delayed and dry southwestern monsoon in the first two months, with late onset, intermittent rains and dry spells in many regions. The farming season may again be pushed back, as it was in 2021.
IMD has forecast a “normal” monsoon this year at 99% of long period average with margin error of +/-5%.
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