why-the-monsoon-is-early

Context: The monsoon hit the Kerala coast two days behind schedule, but has already covered two-thirds of the country.

Monsoon Progress so far:

  • Recently the northern limit of the monsoon (NLM) continued to pass through Diu, Surat, Nandurbar, Bhopal, Nagaon, Hamirpur, Barabanki, Bareilly, Saharanpur, Ambala, and Amritsar, according to the India Meteorological Department’s report.
  • Across some areas of south peninsular and central India, the monsoon has arrived 7 to 10 days ahead of its scheduled date.
  • So far, the monsoon has missed Northwest India (Gujarat, Rajasthan, western Madhya Pradesh, Haryana, Punjab and Delhi).
  • As of 15 June 2021,  the entire country except West Bengal and the Northeast, Jammu and Kashmir and Ladakh, Kerala, and Gujarat had received cumulative rainfall in excess (20%-59%) or large excess (60% or more) of normal.
    • Since the official beginning of the southwest monsoon season on June 1.

Reason Behind early monsoon this year:

  • Cyclone Yaas, formed in the Bay of Bengal during the third week of May, helped the monsoon make a timely arrival over the Andaman Sea on May 21.
  • Despite a two-day delay from its normal onset over Kerala (Normally it arrives on the 1st of June), the southwest monsoon made fast progress in subsequent days.
    • Mainly due to: 
      • Strong westerly winds from the Arabian Sea, and 
      • The formation of a low-pressure system over the North Bay of Bengal on June 11, currently lies over eastern Uttar Pradesh and Bihar.

Is this pre-arrival usual?

  • In the last decade since 2011, the monsoon has covered the entire country in June itself on four occasions i.e., 
    • 2020 ( June 1–26), 
    • 2018 ( May 28–June 29), 
    • 2015 (June 5–26) and 
    • 2013 (June 1–16).
  • In all the other seven years, arrivals were delayed over major cities or regions.
  • Cyclone Vayu in 2019 and Cyclone Mora in 2017 had delayed the monsoon progress by a few days.
  • But overall, advancement during these seven years was as per normal dates and the monsoon covered the country around July 15 (the normal date, followed until 2019).
  • In the years when the monsoon has arrived early, its progress has picked up towards the final phase i.e., 
    • The North and Northwest India regions have witnessed early arrival.

Will this pace continue?

  • Although the monsoon has made rapid progress throughout the country, further progress is likely to be slower.
  • An advance will take place when there is a fresh pulse to revive the monsoon currents.
  • Over Northwest India, the monsoon becomes active only when the monsoon currents (either from the Arabian Sea or the Bay of Bengal) reach the region.
    • This is not expected soon.
  • The stream of mid-latitude westerly winds is approaching Northwest India, which will hinder the monsoon advancement in the immediate coming days.

Does early monsoon mean more rainfall?

  • The time of monsoon onset over a region has no direct impact on the rainfall quantum received during the season, or in the monsoon’s progress.
    • E.g., the monsoon took 42 days in 2014 and 22 days in 2015 to cover the entire country but India recorded deficient rainfall during both years.
  • This year, the monsoon is most likely to cover the entire country by the end of June.
    • Where it is possible that June rainfall could end in surplus over the normal of 170 mm. As of June 15, it was 31% above normal.

Impact of early rainfall on Paddy sowing:

  • Early rainfall will not directly impact paddy sowing, with seedlings still in the nursery stage in most paddy growing states.
  • Due to rainfall over coastal Karnataka and Konkan, farmers can undertake paddy transplanting in the third to fourth weeks of June.

The early monsoon also means a shorter summer. Is this unusual?

  • Although the IMD considers June 1 as the beginning of the monsoon season over India, the summer in Northwest India is not yet over.
  • In West and Northwest India, day temperatures remain above 40°C.
  • Recently, Rajasthan and neighbouring areas of Northwest India reported heatwave-like conditions.
  • Once the low-pressure system weakens in the upcoming weeks, the temperatures over North and Northwest India (where the monsoon is yet to reach) will increase.

Is the current pattern fit with the context of climate change?

  • The onset of the monsoon over various parts of the country each year can be ahead of time, in time or late.
  • These variations are generally considered normal, given the complexity and dependability of the monsoon over the various factors.
  • According to experts, climate experts have linked extreme weather events like intense rainfall over a region within a short time span or prolonged dry spell during these four months as indications of climate change.

Related Facts:

Rice Cropping in India:

  • Rice (paddy) is the season’s main crop.
    • Other principal crops are Jowar, Bajra, Cotton, Sugarcane, Sesame, Groundnut and Pulses.
  • It grows best in an area of warm and humid climate. Rice requires temperatures between 20°C and 35°C and well-distributed rainfall of about 100 cm or irrigation facilities.
  • The soil should be fertile. Delta and valley soils are most suitable.
  • Soil with higher clay content is preferred for its cultivation due to its better moisture retention capacity.
  • The major rice-producing states are West Bengal, UP, Andhra Pradesh, Punjab, Bihar and TN.
  • The important high yielding varieties include IR-8, Jaya, Padma, Hamsa, Sabarmati and IET 1039.

Source: The Indian Express