Why a normal monsoon is a myth – Times of India

Why a normal monsoon is a myth – Times of India

The Indian Meteorological Department (IMD) on Monday said the country is expected to have a ‘near normal’ monsoon this year at 96% of Long Period Average (LPA) – a stimulant signal for farmers and the overall economy.
A normal monsoon is considered to be 96-104% of the LPA of 89 cm for the entire four-month season beginning June to September. Above-normal is 104-110%, below-normal is 90-96% and deficient (drought) is below 90%. LPA is defined as the average annual rainfall over 50-year period between 1951 and 2000.

Of the past 10 years, India’s crucial monsoon rain has been below normal in six years. IMD divides the country into 36 meteorological sub-divisions, mostly corresponding with state boundaries, with big states being divided into 2 or 3 sub-divisions, climatological uniformity based on. In poor monsoon years, some 6-7 sub-divisions suffered more than others, the data shows. On the bright side, two of India’s driest regions have received relatively good rainfall during this period.
A look at the monsoon pattern from 2009-2018:

An El Nino year that saw the weakest monsoon and the worst drought in 37 years, in which 23 sub-divisions received deficient rainfall.



2010 was a vast improvement from the previous year; 14 subdivisions (in blue) had excess rain.


Probably the best monsoon year of this period with the best well-distributed rainfall. No subdivision apart from the north east (in red) had deficient rains



Pacific Although El Nino did not develop. Thirteen sub-divisions received deficient rainfall in 2012 and only Andaman & Nicobar Islands saw a surplus.



The strongest monsoon of the period, with the earliest beginning in decades over north India Cloudbursts caused the deluge in Kedarnath, Uttarakhand. Swathes of blue across the country mean 14 regions received more rain than initially expected.


A drought year with monsoon hit by evolving El Nino conditions After several years of poor monsoon, the northeast received normal rainfall, but 11 regions saw a deficit.



An El Nino Year that lead to the second straight drought year Agriculture output dipped and water shortages abounded Poor rain hit 17 sub-divisions, this included the west coast. Rajasthan, in blue, was the only area that got over rain


First normal monsoon in three years Agriculture output grew after a two-year lows Four regions saw excess rain



It was a below-normal monsoon year with most of the north and parts of central India in rain shadow. Five sub-divisions saw excess rain, while more than two-thirds of India, or 25 sub-divisions, had normal rainfall.



2018 was the year However, rains were better than distributed in 2017, with North India, for once, getting satisfactory rain. Twelve areas saw deficits Kerala, however, saw excess rainfall which led to devastating floods.

2018 was an 'almost drought' year. Kerala, however, received excess rainfall

2018 was an ‘almost drought’ year. Kerala, however, received excess rainfall

Haryana, Punjab among worst-hit regions
Vidarbha makes news for farmer suicides but rains have failed in the sub-division in just two years over the past decade. The story is too bleaker in the neighbouring Marathwada.


Most subdivisions in the above list are invariably the hardest hit during weak monsoon years.
Regions that received excess rain
Konkan and Goa, India’s second wettest sub-division of over-rains in the past 10 years, increasing the danger of floods, in particular in Mumbai.
Surprisingly, two of India’s driest regions have clocked excess rainfall on most years since 2009. In the average rainfall in West Rajasthan is just 263.2mm during June-Sept, making it the driest sub-division of India. Saurashtra and Kutch are at No. 4 (average rain 477.5mm).


How accurate are weather forecasters?
IMD’s forecast for 2019 directly challenges the prediction of India’s only private sector weather forecaster, Skymet, which is slightly more pessimistic with a forecast of 93%. Both the IMD and Skymet have hit the bull’s eye an equal number of times in the last six years. IMD was off the mark in 2014, 2015 (which turned out to be the worst years) and 2018, which narrowly escaped a drought.


Source: IMD


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