Technology Inceptions: New Device Detects Decline in RBC Volume Causing Blurred Vision in Alcoholics  |  National Edu News: GATI, CURIE, WISTEMM, Vigyan Jyoti for attracting Women to Science & Tech  |  Rajagiri Round Table: Roadmap to Excellence in Research and Innovation  |  Policy Indications: Should Climate Change Communications be Emotional?  |  Science Innovations: Scientists Understand the Logistics of Protein Movement in a Cell  |  Health Monitor: Eating Disorders Linked to Psychiatric Disorders and Risk of Obesity  |  Science Innovations: The Mystery of the Flying Volcanic Ash Particles Revealed  |  Policy Indications: UK Graduate route to open to international students on 1 July 2021  |  Leadership Instincts: VP appeals to students to connect their knowledge with social relevance  |  Leadership Instincts: Catherine Dulac receives Nomis Distinguished Scientist and Scholar Award  |  Leadership Instincts: Online school reviews reflect school demographics more than effectiveness  |  Leadership Instincts: Researchers virtually open and read sealed historic letters  |  Cover Story: At Vantage Point  |  Management lessons: Why Aluminium Cans are Great for Packaging of Beverages?  |  Parent Interventions: Motivation to Perform  |  
December 21, 2020 Monday 11:55:05 AM IST

Disturbance from North Atlantic capable of derailing the Indian monsoon

National Edu News

A planetary wave from the North Atlantic is capable of derailing the Indian monsoon on which the Indian economy is heavily dependent, suggests a study published in the journal Science. The findings suggest that modelling efforts ought to focus on including the influence of mid-latitudes, in addition to the Pacific and Indian oceans, for getting a better handle on predictability of the monsoon, its variability as well as droughts.

A team from the Centre for Atmospheric and Oceanic Sciences (CAOS), Indian Institute of Science (IISc), who carried out the research, supported in part by DST under their climate change programme, showed that, in the past century, Indian monsoon droughts that occurred in non-El Niño years were sub-seasonal, as against El Niño droughts, where the deficit persists throughout the season.

The research team analysed daily rainfall during the two categories of droughts from 1900 to 2015 and noticed dramatic differences in the evolution of rainfall deficit. Rainfall deficit in El Niño droughts sets in early around mid-June and becomes progressively worse. By mid-August, the deficit is very high and spread across the country, with no sign of recovery. 

During non-El Niño droughts there is a moderate decrease in June rainfall, followed by signs of recovery during mid-July to mid-August ‒ the peak of the season.  However, in late August, there is an abrupt and steep fall in rainfall, resulting in drought conditions.


“We tried to trace this late August break to a forcing agent or system that influences the behaviour over India. We looked at the winds that were prevalent in these non-El Niño drought years,” said Jai Sukhatme, Associate Professor at CAOS, and one of the senior authors, in an IISC statement.

“The interaction between upper-level winds and deep cyclonic vorticity anomalies located above anomalously cold North Atlantic waters during late August to early September results in an atmospheric disturbance. This disturbance, a Rossby wave, curves in towards India and, apparently squeezed in by the Tibetan Plateau, disrupts the flow of the monsoon winds,” V Venugopal, Associate Professor at CAOS, and a co-author explained.

The atmospheric tele-connection studied in this paper whose first author was a PhD student Pritam Borah with DST inspire fellowship, offers an avenue for improved predictability of droughts, especially in the absence of tell-tale signs in the Pacific.


Comments