Core monsoon saw suppressed rainfall, trough to shift again towards the Himalayan foothills early next week
Photo: iStock The current monsoon break that started on August 7, 2023 has finally ended, according to the regional centre of India Meteorological Department, Pune. This current monsoonal break makes it the third-longest for this century after 2002 and 2009.
The current break spell that ended on August 18, 2023 was a robust one, according to Akshay Deoras, climate scientist at the University of Reading, the United Kingdom.
Source: Pulaha Roy
“The core monsoon saw suppressed rainfall, which was enough to pull down the all-India cumulative monsoon rainfall anomaly from seven per cent to -6 per cent in less than a month,” Deoras said.
Read more: It’s make or break for rice production in monsoon 2023
A monsoonal break, according to Deoras, occurs when the monsoon trough shifts northward, which enhances rainfall along the Himalayan foothills and parts of eastern India while rainfall is suppressed in the rest of the country.
This happens especially in the core monsoon zone area or the region stretching from Gujarat in the west to West Bengal and Odisha in the east, where agricultural activities are rain-fed.
But while the above development is based on meteorology, climatologically, a monsoonal break is declared when normalised rainfall anomaly index or deviation from the long term rainfall average over the core monsoon zone exceeds -1 threshold and the situation persists for at least three consecutive days, Deoras explained.
“The break monsoon ends when the normalised rainfall anomaly decreases in magnitude”, Deoras added.
So, will the end of the monsoon break bring some respite?
“The monsoon trough will again shift towards the Himalayan foothills early next week and remain locked there until the end of August. This will reduce rains in central India once again. So, the termination of the current break monsoon is not an indication of the monsoon reviving in the country,” Deoras said.
A combination of factors were at play behind this decade-high monsoonal break, said the climate scientist.
Read more: More dry days ahead? Monsoon on continuous break for past 11 days
“The developing El Nino played a role in prolonging the break monsoon and making it intense. Of course, it was supported by the absence of sub-seasonal weather patterns that boost rainfall as we saw in July 2023,” Deoras said.
While a monsoonal break from an active phase is quite normal, what is alarming about the current situation is that the break persisted for a prolonged period of time.
While a monsoon season might feature multiple break spells, to assess how dire the situation is currently, Down To Earth accessed data on longest consecutive break spells since 1951.
According to the data, in the last 73 years, there have been a total of 10 instances when the break spell has stretched over 10 days.
The longest consecutive break spell was reported in 1972, when the core monsoon zone did not receive any rainfall for 17 days at a stretch, while in 1966 and 2002, the break spell stretched over 10 days on multiple occasions.
The current break spell comes at a time when the government declared a ban on the export of rice, the most important Kharif crop.
While there’s still a month and half for the monsoon to retreat from the subcontinent, it remains to be seen how Kharif production fares this season.
Monsoon 2023 has been six percent deficit when compared to the long term average but ‘normal’ as per IMD’s rainfall categorisation. But a closer look suggests that the distribution has been skewed.
A total of 264 out of 717 districts remain deficient to large deficient.
Another anomaly that stands out in 2023 has been the drier western regions, specifically the West Rajasthan and Saurashtra-Kutch meteorological subdivisions receiving large excess rainfall while the usually wetter regions like Kerala, Gangetic West Bengal, Bihar and Jharkhand remaining dry due to deficient rainfall.
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