Chennai has recorded unprecedented rainfall that has surpassed century-old records. The rare event, according to experts, maybe linked to the global meteorological event called El-Nino, which is usually associated with a dry monsoon spell in India.
The official
Chennai has recorded unprecedented rainfall that has surpassed century-old records. The rare event, according to experts, maybe linked to the global meteorological event called El-Nino, which is usually associated with a dry monsoon spell in India.
The official meteorological reason for the current spell of rains is the following. "...a slow-moving depression over southwest Bay of Bengal has triggered the fresh bout of heavy rain in Tamil Nadu... from a cyclonic storm that hit the state in November." However there are larger climate forces at play.
In El-Nino years, surface water temperatures in the Pacific Ocean rise between 0.5 to 1 C, causing warm air to rise and the colder, moisture-laden air that brings monsoon rain to India is pulled away from the mainland. During India's winter, when rainfall--governed by a separate weather system-- generally tends to occur in northern Andhra Pradesh and Tamil Nadu, the El Nino generally whets cyclones in the Bay of Bengal and brings some rain to the Orissa coast, West Bengal, parts of Andhra and Tamil Nadu.
This year, the El Nino has been extremely strong--the most in over 18 years--and coupled with unusually-cold sea-surface waters near the Tamil Nadu and Kerala coast, has gravitated extra gusts towards Chennai, says Mahesh Palawat, Chief Meteorologist, Skymet Weather, a private weather forecasting agency. "Normally, rains that would have gone on upwards towards Andhra Pradesh are now turning south towards Tamil Nadu," he added. "It is an unusual situation because