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Sri Lanka hit by record drought from Indian Ocean Dipole event

By Asantha Sirimanne

Jan 13, 2017 15:05 PM GMT+0530 | 0 Comment(s)

SEE SAW:  Temperature oscillations which cools the Eastern Indian Ocean (negative phase) can cause droughts in Sri Lanka.

ECONOMYEXT - Sri Lanka's record drought in 2016, perhaps the worst in over 40 years was due to a stronger than usual sea temperature fall in the Western Indian Ocean, officials said.

Sri Lanka's main South East monsoon from May to August effectively failed with most of the rain confined to a few days, and the North East monsoon was delayed until mid-December and brought about half the rainfall compared to an average year up to now, meteorological officials say.

During a so-called Indian Ocean Dipole negative event, cooling seas in the Westen Indian Ocean reduces moisture in monsoon winds.

"A Negative Indian Ocean Dipole event was the basic reason for the drought," H M C Premalal, Director Meterological Department said.

Like the El Nino-Southern Oscillation in the Pacific Ocean and the La Nina that follows, the Indian Ocean Dipole is a major driver of weather from Madagascar to Australia. The current negative event has coincided with a weak La Nina.

A negative IOC phase brings cooler sea-surface temperatures in the Western Indian Ocean and lower rainfall for Sri Lanka. There can be floods in the Eastern Indian Ocean area.

Anusha Warnasuriya, Deputy Director at the Met Office forecasting division says the IOD negative phase which began in July 2016 is believed to be one of the strongest known such events.

As a result Sri Lanka winds during South West monsoon, which usually blow from South-South Westerly direction had come from North Westerly direction from the Indian landmass in 2016, travelling over less sea and bringing less moist air.

The North Eastern monsoon winds and also come from a more northern direction also carrying less water.

At the moment Sri Lanka is also experiencing cold temperatures due to cool air coming from India. Temperatures in the capital Colombo at 2 to 3 degrees below normal and in higher elevations like Kandy about 5 degrees below normal, Premalal said.

Farmers in highland areas have been advised to light small bonfires to protect crops from frost.

Though the North East monsoon winds will continue for the next two months and some rain is expected from around January 17 - 18, rainfall so far had been below average.

The drought could be the worst seen since 1973/74 in Sri Lanka's dry zone. Sri Lanka is expected to get about third of the rice harvest during the current main Maha cropping season

The government has stopped issuing water for agriculture in many areas to preserve water for drinking. Sri Lankans should use conserve water and also electricity with hydro-power generation badly hit, official said.

"Don’t' use water for things like washing cars," Disaster Management Minister Anura Yapa said. His ministry is already distributing water by tankers to the hardest hit villages.

With January and February being the driest months of the year, conditions are expected to get worse before inter-monsoonal rains come in March and April.

Though rainfall is expected to be normal in 2017, Sri Lanka's minor Yala cropping season in the second half of the year is also expected to be hit due to low starting reservoir storage. (Colombo/Jan13/2016)
 


 

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