New Delhi: India is expected to get above-normal rainfall in the upcoming southwest monsoon season, the India Meteorological Department said on Tuesday, raising hopes for a bountiful harvest for the largely agri-based economy.
According to the long-range monsoon forecast, the IMD said large parts of Tamil Nadu and the northeastern region were likely to get below-normal rainfall, while the rain-deficient parts of Marathwada and adjoining Telangana are expected to witness above-normal showers.
“India is likely to see above-normal rainfall in the four-month monsoon season (June to September), with cumulative rainfall estimated at 105 per cent (with a model error of 5 per cent) of the long-period average of 87 cm,” M Ravichandran, secretary in the Earth Sciences Ministry, told a press conference here.
The southwest monsoon lasts from June 1 to September 30.
He said that of all the global factors that influence monsoon rainfall over India, two will have a neutral impact, and one will have a positive impact on rainfall this year.
“There is a 30 per cent chance of normal rainfall, a 33 per cent chance of above-normal rainfall, and a 26 per cent chance of excess precipitation during the monsoon season,” IMD Director General Mrityunjay Mohapatra said.
According to the IMD, rainfall between 96 per cent and 104 per cent of a 50-year average of 87 cm is considered ‘normal’.
Rainfall less than 90 per cent of the long-period average is considered ‘deficient’, between 90 per cent and 95 per cent is ‘below normal’, between 105 per cent and 110 per cent is ‘above normal’, and more than 110 per cent is considered ‘excess’ precipitation.
Parts of Jammu and Kashmir, Ladakh, Tamil Nadu, Bihar and the northeastern states are likely to experience below-normal rainfall during the monsoon season.
Normal to above-normal monsoon rainfall is expected in large parts of Madhya Pradesh, Rajasthan, Maharashtra, Odisha, Chhattisgarh, Uttar Pradesh and West Bengal, which form the core monsoon zone (agriculture primarily rain-fed) of the country.
Parts of the country are already battling extreme heat, and a significantly high number of heatwave days are expected in the April to June period. This could strain power grids and result in water shortages.
The monsoon is crucial for India’s agriculture sector, which supports the livelihood of about 42.3 per cent of the population and contributes 18.2 per cent to the country’s GDP.
It is also crucial for replenishing reservoirs critical for drinking water, apart from power generation across the country. A prediction of normal rainfall during the monsoon season, therefore, comes as a huge relief.
However, normal cumulative rainfall does not guarantee uniform temporal and spatial distribution of rain across the country, with climate change further increasing the variability of the rain-bearing system.
Climate scientists say the number of rainy days is declining, while heavy rain events (more rain over a short period) are increasing, leading to frequent droughts and floods.
Three large-scale climatic phenomena are considered for forecasting monsoon season rainfall.
The first is ENSO — a climate pattern characterised by fluctuations in sea surface temperatures in the tropical Pacific Ocean, which in turn affects global weather patterns.
The second is the Indian Ocean Dipole, which occurs due to differential warming of the western and eastern sides of the equatorial Indian Ocean while the third is the snow cover over the northern Himalayas and the Eurasian landmass, which also impacts the Indian monsoon through differential heating of the landmass.
ENSO-neutral conditions and neutral Indian Ocean Dipole conditions are predicted during the season. Also, the snow cover in the Northern Hemisphere and Eurasia is low, Mohapatra said.
