Tuesday, June 3, 2014

DailyMail: Drought fears sparked by El Nino threat as monsoon fails to hit Kerala on time







It is now more or less clear that this year's forecasts of a Super El Nino was just hype. What we should be getting is a weak or at the most a moderate intensity event.  This makes its likely impact on global temperatures minimal. However, the converse may not hold true in relation to the Indian Monsoon this years. Though the El Nino effect maybe minimal, it is the behaviour of the Indian Ocean Dipole (IOD). The IOD is presently neutral with a slightly positive bias. But if it flips to its negative mode, then we can still stare into the face of one of the worst droughts in recent times.


India's life-giving season of rain has already missed its scheduled June 1 date with Kerala, and there's a one-in-four chance that the delay could turn into a full-on drought.

It is said that the mechanism of the Indian monsoon is understood by every schoolboy but the experts don't have a watertight theory yet.

Add to that the not-so-well understood El Nino phenomenon - an upwelling of warm water in the eastern Pacific that has a far-reaching effect on regional weather patterns across the globe - and the picture starts drying up for India.

Private forecaster Skymet more or less agrees with IMD, but has responded ominously to the Kerala disappointment.
"Its (the monsoon's) further progress is likely to be staggered and slow," says GPS Sharma of Skymet.
Slow movement

The widespread fears of delayed rains have arisen from the slow advancement of the southwest monsoon over the Andaman Sea, which normally occurs around May 20 every year, with a standard deviation of about a week.

A scientist in the Ministry of Earth Sciences told Mail Today that it is too early to say whether India will witness drought-like conditions, but acknowledged that a low pressure system in the Indian Ocean is affecting the flow of the monsoon current.
India monsoon

Even as fears loom large of a delayed and weak monsoon, the Met Department has claimed that conditions are becoming favourable for the onset of rains over Kerala and its further advance into more parts of South Arabian Sea, remaining parts of the Maldives-Comorin area, some parts of Tamil Nadu and Bay of Bengal and few parts of the northeastern states during the next three to four days.

The IMD has forecast the onset of the monsoon over Kerala on June 5, with a model error of plus or minus four days.

The monsoon normally sets in over Kerala on June 1 every year and its onset signals the commencement of the rainy season across the region.

Indicators


Last year, the monsoon set in over Kerala on June 1 while in 2012, it had set in on June 5. In 2011, Kerala started receiving rainfall on May 29 while a year earlier, the monsoon reached the state on May 31.

In 2009, rains struck the coastal state on May 23. Operational forecasts for the onset of the monsoon are issued on the basis of six indicators – minimum temperature over northwest India, pre-monsoon rainfall peak over the southern peninsula, outgoing long-wave radiation over South China Sea, lower tropospheric zonal wind over southeast Indian Ocean, upper tropospheric zonal wind over east equatorial Indian Ocean and outgoing long-wave radiation over southwest Pacific region.

Allaying fears of a delayed monsoon, the head of IMD's forecast department, B.P. Yadav, said:
"From the ground parameters, the conditions are favourable for the onset of monsoon over Kerala and we stick to our forecast of monsoon striking Kerala on June 5, with a margin of four days. There are no changes in the given forecast."
A scientist in the Ministry of Earth Sciences told Mail Today that it is too early to say whether India will witness drought-like conditions, but acknowledged that a low pressure system in the Indian Ocean is affecting the flow of the monsoon current.
India monsoon

Even as fears loom large of a delayed and weak monsoon, the Met Department has claimed that conditions are becoming favourable for the onset of rains over Kerala and its further advance into more parts of South Arabian Sea, remaining parts of the Maldives-Comorin area, some parts of Tamil Nadu and Bay of Bengal and few parts of the northeastern states during the next three to four days.

The IMD has forecast the onset of the monsoon over Kerala on June 5, with a model error of plus or minus four days.

The monsoon normally sets in over Kerala on June 1 every year and its onset signals the commencement of the rainy season across the region.

Last year, the monsoon set in over Kerala on June 1 while in 2012, it had set in on June 5. In 2011, Kerala started receiving rainfall on May 29 while a year earlier, the monsoon reached the state on May 31.

In 2009, rains struck the coastal state on May 23. Operational forecasts for the onset of the monsoon are issued on the basis of six indicators – minimum temperature over northwest India, pre-monsoon rainfall peak over the southern peninsula, outgoing long-wave radiation over South China Sea, lower tropospheric zonal wind over southeast Indian Ocean, upper tropospheric zonal wind over east equatorial Indian Ocean and outgoing long-wave radiation over southwest Pacific region.

Allaying fears of a delayed monsoon, the head of IMD's forecast department, B.P. Yadav, said:
"From the ground parameters, the conditions are favourable for the onset of monsoon over Kerala and we stick to our forecast of monsoon striking Kerala on June 5, with a margin of four days. There are no changes in the given forecast."



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