In 2022, 13 subdivisions had reported ‘large deficient’ rainfall compared to 18 this year
Photo: iStock. The India Meteorological Department (IMD) declared the onset of southwest monsoon in mainland India on June 8, 2023. Some 29 of the 36 — accounting for 81 per cent — IMD subdivisions registered deficient to large deficient rainfall.
Unlike administrative boundaries like states and districts, meteorological subdivisions are demarcated after considering their similarity in climatic patterns. While Mumbai comes under Maharashtra, the region’s climate is similar to that of the Konkan coast (as shown in the map).
As depicted in the map below, large parts of India have been witnessing ‘deficient’ to ‘large deficient’ rainfall, meaning the onset of monsoon has been weak. While IMD accurately predicted the onset date — June 4, 2023, with an error margin of four days — Skymet, a private weather forecasting agency, indicated the advancement of the southwest monsoon to be bleak.
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A graph showing the sluggish progress of the monsoon. Source: Pulaha Roy.
Skymet predicted inadequate rainfall through July 6, 2023. But does that mean the monsoon has currently stalled?
For the monsoon to progress northwards, the summertime dry air over India has to be replaced by moist air from southwards — which is brought about by monsoon circulation, according to Akshay Deoras, a climate scientist at the University of Reading, the United Kingdom.
“Currently, monsoon winds are weak so this dry air is firmly placed over the country,” Deoras added.
Deroas also pointed out a combination of factors — lack of favourable interseasonal activity such as the low-pressure system in the Bay of Bengal and the impact of El Nino — are the reasons behind the sluggish start to the monsoon.
“The large deficit over southern, central eastern and northeastern parts of India clearly reflects the sluggish progress of the monsoon,” he said.
El Nino is the warm phase of a climate pattern across the tropical Pacific called the El Nino-Southern Oscillation (ENSO).
Watch video: How have Cyclone Biporjoy and El Nino influenced the monsoon in India?
To put some context, Down To Earth also plotted the monsoon progress in 2022. While the deficit pattern of 2022 and 2023 looks similar at first glance, a granular analysis of the sub-divisional data shows the contrasts.
In 2022, 13 subdivisions had reported ‘large deficient’ rainfall compared to 18 this year. And some 30 subdivisions reported deficient to large deficient rainfall last year compared to 29 in 2023. Further, 16 subdivisions reported deficient rainfall in 2022 compared to 11 in 2023.
DTE has been following the progress of the monsoon ever since the southwest monsoon winds were tracked near the equator, and since then, it has been a stop-start trajectory for monsoon 2023.
While the monsoon crossed halfway through the Bay of Bengal, Typhoon Mawar stalled the winds, and there was no advancement from May 19-May 29, 2023. Since then, the monsoon has made steady progress even though it has been weak before the current stalling phase that has hit again.
Saurashtra-Kutch and Western Rajasthan have reported excess rains due to Cyclone Biporjoy rather than the southwest monsoon. The cyclone, which is currently brewing in the Arabian Sea, is expected to make landfall on June 15, 2023.
However, unlike typhoon Mawar, cyclone Biporjoy hasn’t affected the progress of the monsoon, according to Deoras.
The monsoon season usually brings respite to intense heat prevailing over the country and is directly responsible for the crop produced during the Kharif season.
Skymet predicted the current stalling to stretch till July 6, coinciding with the sowing season.
“Inadequate rains over the central and western parts, the core monsoon zone will find it difficult to absorb the drying effects, rather early in the season. It is likely to leave the poor farmers in a state of indecisiveness choosing between the type of crop and the crop cycle”, the private weather agency said.
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