Research reveals that Disturbance from North Atlantic could be possible reason why Indian monsoon derails in August.
As part of the Government of India’s vision of SAGAR (Security And Growth for All in the Region), the Indian Navy has been proactively engaging with countries in the Indian Ocean Region for coordinated patrols, cooperation in EEZ surveillance, passage exercises and bilateral/multilateral exercises, towards enhancing regional maritime security
Findings of the Study:
- According to a study published in the journal ‘Science’, a planetary wave from the North Atlantic is capable of derailing the Indian monsoon.
- 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.
- The research team analyzed 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.
- The research shows that in the past century, the 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 was carried out by a team from the Centre for Atmospheric and Oceanic Sciences (CAOS), Indian Institute of Science (IISc), supported in part by the Department of Science & Technology.