The 2023 monsoon season in India concluded with a total rainfall of 94.4%, and its impact on the monsoon rains was less significant than anticipated, according to the Indian Meteorological Department (IMD). During a briefing, Mrutyunjay Mohapatra, the Director-General of IMD, stated that despite the presence of the El Niño phenomenon in the Pacific Ocean, positive factors countered its influence, allowing the monsoon to maintain its strength. He noted that the monsoon, itself a robust meteorological phenomenon, played a crucial role in sustaining rainfall in the country.
Mohapatra highlighted two factors — the Indian Ocean Dipole and Madden-Julian Oscillation (MJO) — as having greatly influenced this year's monsoon season. According to him, MJO is the most important factor that countered the effect of El Nino — warming of waters in the Pacific Ocean near South America — on the monsoon season in India.
The IMD DG stated that 15 low-pressure systems developed over India during the monsoon season against an average of 13, but their temporal distribution was skewed.
As of September 29, the countrywide cumulative rainfall deficiency stood at 6% of the long-period average (LPA) for the entire season. India recorded a total of 814.9 mm of rain compared to the normal average of 865 mm.
The monsoon season began with concerns about El Niño, which typically weakens the Indian monsoon due to unusual warming of surface waters in the eastern Pacific Ocean. However, despite the initial worries, June and July largely evaded the effects of El Niño.
The monsoon's journey was not without challenges. The season began with a sluggish start, resulting in a 10% rainfall deficit in June. Cyclone Biparjoy, originating in the Arabian Sea, initiated the monsoon's onset over Kerala but also disrupted its progress, leading to a double-digit rainfall deficiency in June.
July saw rains across the country, except in East and Northeast India. In the second half of the season, August recorded an all-time low in cumulative rainfall due to prolonged 'break monsoon' conditions. Several states, including Gujarat, Kerala, Rajasthan, Karnataka, and Telangana, reported significant rainfall deficiencies.
With the threat of drought looming after a disappointing August, the monsoon saw a revival in the second week of September, due to a trail of monsoon systems in the Bay of Bengal. Monsoon rainfall deficiency improved from -11% on September 1 to -6% on September 29.
However, certain regions, such as parts of South Peninsula India and East & Northeast India, remained in deficit throughout the season.
Monsoon 2023: Rainfall Deficiency In States And El Niño Impact Ahead
Kerala reported a high rainfall deficiency of -36%, followed by Jharkhand at -27% and Bihar at -24%.
Looking ahead, El Niño is expected to persist through the Northern Hemisphere winter of 2023-24, with a likelihood exceeding 95% through December-February 2023-24. Although it is anticipated to be moderate to strong, historical statistics suggest that El Niño tends to result in 'below-normal' rainfall in India during the monsoon season. Approximately 60% of El Niño years have led to below-normal monsoon rainfall in the country, as per the IMD.
The 2023 monsoon season in India, while posing initial challenges and concerns related to El Niño, ultimately concluded with rainfall at 94.4% of the long-term average, reflecting the resilience of the Indian monsoon system in the face of external influences.