IMD may further improve its models to predict deficit and excess rainfall
The southwest monsoon officially ended India with 87.4 cm of rain between June and September, or just 0.7% less than the historical average of 88 cm. In many ways it was an extraordinary year. By the end of August, India was staring at an all-India monsoon rainfall deficit of around 9%. This was mainly due to monsoon rains in August, usually the second heaviest month, falling 24%. At the onset of monsoon, the India Meteorological Department (IMD) had predicted “normal” rainfall with a “trending to the positive side” and the August failure had backfired slightly. It forecast – correctly – heavy rains in September – but maintained that the overall monsoon rainfall, while being “normal”, would be towards the lower end. However, the September rains – 35% above the monthly normal – were so spectacular that it closed the deficit completely and was well beyond the IMD’s expectations. Normally, India receives about 17 cm of rain in September, but this year 22.9 cm of rain was higher than August’s 19 cm.
Monsoon 2021 set the limit for healthy three years of rare rainfall. In 2020, India received 109% of the Long Period Average (LPA) and in 2019, 110% of the LPA, and since 1996, 1997 and 1998, India has received normal or above normal rainfall for three consecutive years. Most of the rainfall was concentrated over southern India, with below-normal rainfall over large parts of northeastern and eastern India, but this is not related for two reasons: the base level of monsoon rains is higher in the northeastern regions than in the rest of India And the region also experiences a retreating monsoon which usually starts by the end of October. Three years of good rains have boosted storage in India’s major reservoirs. However, the monsoon proved to be uncertain for agriculture. two major months for Kharif The sowing of the crop, July and August, were those when the monsoon failed and the excess rainfall of September meant that there was a real possibility of crop loss due to excessive moisture. Government is expecting record crop production Kharif The crop yield is expected to be 150.5 million tonnes by June 2022, slightly higher than the 149.56 million tonnes harvested last year. There is expected to be a record surplus for rice, pulses and oilseeds. While this may benefit exports, it may also mean demand for more remunerative prices by farmers. These extra rains may be a rare occurrence but the government should take advantage of it and ensure adequate stock for the next year. The IMD should not be satisfied that it has got its overall prediction correct, but should analyze how its model can be improved to predict deficit and excess rainfall.
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