Gains from rains: on monsoon performance

Context

- So far, India appears to be having a good run with the monsoon. As of the most recent data available from the India Meteorological Department (IMD), rainfall during the season has been 14% more than what is usual for this period.

Monsoon pattern in India

- The month of June only accounts for about 17% of the monsoon rainfall spanning June-September.

- It is the month during which the monsoon sets in and that process can sometimes be delayed for as much as a week.

- June is also when the monsoon begins its journey from two extremities of the country.

- One branch starts its journey northwards from Kerala and the other wing — called the Bay of Bengal branch — enters India from the southeast.

- Both branches eventually converge in the north and usually, this merging and strengthening of the monsoon currents over the mainland take at least until July 15.

- The IMD never forecasts the possible rainfall likely during June because of the vagaries involved in the onset and the pace of the journey.

2020 monsoon pattern (Important data)

- This year, two significant things happened. The monsoon set in on a textbook date of June 1.

- This was even after concerns that Cyclone Amphan that had ravaged West Bengal would delay the monsoon’s entry into India from the Andaman Sea.

- The second factor was the record pace at which the monsoon covered the country.

- Along with the monsoon onset this year, the IMD announced a revision to the onset and withdrawal dates across several cities.

- According to this, the monsoon covered India’s northern and western borders no later than July 8 as opposed to the previous historical date of July 15.

- This year, however, the monsoon broke even this speed limit and covered the country by June 25 — at a pace that was unprecedented since 2013.

- The net result of all this: more rainy days in June and a fairly even distribution across the country.

- The IMD’s records show that only on four days in that month did daily rainfall drop below its historical normal.

- Except for northwest India, which is staring at a 3% deficit, the rainfall in east, south and central India has posted surpluses of 13%-20%.

- While good rains in June signal farmers to prepare the soil and sow kharif crop, the most important months are July and August.

- These two months account for two-thirds of the monsoon rain. This is also the time the monsoon goes into so-called ‘break’ conditions.

- Prolonged breaks, or an absence of rainfall, can even lead to drought.

Way ahead

- In spite of significant improvements in data gathering and technological advancement, meteorological agencies cannot yet reliably forecast the advent of a break or how long it can last.

- What is critical is that ‘normal rains’ also obscure the possibility of heavy rains or severe droughts in districts or over larger areas. Therefore, short and medium-range forecasts need to be strengthened and effectively communicated to the people.