IMD Announced Early Arrival Of Monsoon? Where Did IMD Go Wrong?

The India Meteorological Department (IMD) on Sunday announced the arrival of south-west monsoon in Kerala three days ahead of schedule.

However, independent experts have questioned the IMD announcement as the criteria laid down by IMD were not met the day announcement were made.

They highlight that the monsoon's arrival is announced when eight weather stations in Kerala, Lakshadweep, and Karnataka receive a minimum of 2.5 mm of rainfall for two consecutive days, but only five stations received this on the day of IMD's announcements.

This meant that IMD made the announcement against its own criteria. 

Here we explain what independent experts have said, how the IMD is justifying itself, and what does the controversy mean.

What's the criteria to call it monsoon

The Hindustan Times rerpoted that there are three components of IMD's criteria to declare the arrival of monsoon — the wind pattern is south-westerly, the utgoing Longwave Radiation (OLR) is low, and at least 60 per cent of 14 the following stations — Minicoy, Amini, Thiruvananthapuram, Punalur, Kollam, Allapuzha, Kottayam, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kudulu and Mangalore — report rainfall of 2.5 mm or more for two consecutive days.

While wind-pattern and OLR were right on Sunday, the rainfall criteria was not met, putting the IMD's announcement into question. 

"Onset conditions were fulfilled only for one day, May 29. Day prior (May 28) and day later (May 30) only 40 per cent of the designated stations met the rainfall criteria," said private forecaster Skymet said in the statement quoted by Business Standard. 

What are the allegations

Simply, the allegation is that the IMD announced the arrival of rainfall against its own criteria, meaning it announced the monsoon when it has not technically arrived. 

The IMD Director General Mrutyunjay Mohapatra said the deviation did not make a "huge difference".

He told HT, "Even if we don’t meet the rainfall criteria for the second day, it doesn’t make a huge difference. The criterion was met on Saturday which is why onset was declared. We cannot expect that the criteria will be met every day. Tomorrow again rainfall will increase."

However, experts said it affects the well-established trend and the reputation of the institution.

Independent meteorologist Akshay Deoras told HT, "The monsoon’s onset over Kerala is a well-defined event. The onset criteria are based on the findings of multiple research studies spanning over five decades, which nicely link large-scale atmospheric conditions of the monsoon to rainfall occurring over Kerala. Thus, there should not be any room for subjectivity or assumptions in the onset declaration."

"Declaring monsoon based on single day observations amounts to gross violation of standards, never attempted in the past. Such a step, if taken knowingly, becomes highly objectionable and if otherwise, amounts to an illusion of knowledge," Skymet was quoted as saying by Business Standard.

It added that any reputed scientific body can ill afford to bend rules and criteria just to prove the forecast right.

Implications of premature announcement

Besides its affect on its reputation, the alleged premature announcement could have real-world implementation on agricultural activities. 

It also means that the public is under the impression that the monsoon has arrived when it has actually not.

Skymet, cited by Business Standard, said its observations show the monsoon had not yet arrived over the Kerala coast, and on May 30, seven out of the 14 earmarked stations had recorded nil rainfall and two more locations had registered less than 1 mm rainfall.

The onset criteria must not be overlooked since it could affect research and planning of agricultural activities in India, said Deoras quoted above. 

Skymet's Vice President Mahesh Palawat said, "For example, from the current projections we can say that south Maharashtra, Madhya Maharashtra, Telangana, Andhra Pradesh, Karnataka, Kerala and Tamil Nadu will receive good rains around June 10. So farmers there should wait for rains for sowing or they have to re-sow which has a huge cost. There is political pressure to declare monsoon onset but these aspects are important."