Sunday, June 21, 2009

Deficit monsoon sparks fear of drought

Defying computational forecasts and despite an early start, India’s monsoon has delivered 45 per cent lower than normal rainfall this month, according to weather scientists.

They have cautioned that if rainfall in July — the second month of the four-month monsoon season — doesn’t make up for the deficit, India may experience drought-like conditions this year.

Twenty-eight of India’s 35 meteorological subdivisions have so far received what weather scientists call deficient (more than 20 per cent below normal) or scanty (more than 60 per cent below normal) rainfall. Hot and dry weather has persisted across central, northern, and eastern India.

Although the monsoon set over Kerala on May 23 — a week ahead of schedule — rainfall between June 1 and June 17 was 39.5mm instead of a normal of 72.5mm — a 45 per cent deficit.

“We haven’t seen any fresh surge of the monsoon from the Bay (of Bengal), and wind conditions have remained unfavourable,” Ajit Tyagi, director-general of the India Meteorological Department told The Telegraph today. “The movement we expected from low pressure zones in the Bay did not take place.”

At least twice this month, the IMD had used numerical forecasts — computational simulations of future weather conditions — to predict that a low pressure zone in the northern Bay of Bengal would revive the monsoon during the second or third week of June.

“This is a cause for concern,” said Madhavan Rajeevan, a senior meteorologist and director of a national atmospheric radar facility in Gadanki, Andhra Pradesh. “The July rainfall is going to be crucial. We have sometimes had similar delays in the past, but bountiful rains in July can make up for the delays.”

In its long range forecast issued earlier this year, the IMD had predicted a 96 per cent, or near normal monsoon for 2009. The forecast is still valid, although the IMD had pledged in April this year that it would update the long range forecast and issue separate forecasts for four regions of India in June this year.

Meteorologists say there is no cause for alarm yet because June typically accounts only for 16 per cent of the total rainfall that India receives from June through September.

“But if we don’t get enough rain in July... if by the end of July, we still have a 20 or 25 per cent deficit, India may be looking at a possible drought,” said Rajeevan, who was earlier at IMD, which is involved in monsoon forecasts. “The second half of the season (August and September) will not be able to make up,” he said.

The IMD said today weather conditions over the western and northwest Bay of Bengal may push the monsoon further into Andhra Pradesh and Orissa within three days. But in the absence of a strong surge, the monsoon is not likely to advance over central India during the next week.

Agrometeorologists said crop performance in India’s rainfed areas would now depend on the behaviour of the rainfall during July. Rice, India’s staple, is transplanted during this period and requires plenty of water.

“The soil in vast areas is dry. The distribution and the quantum of July rainfall will have to be good,” said Vyas Pandey, head of agrometeorology at the Anand Agricultural University, Gujarat. “The delay is likely to cause concern in rice growing regions of eastern and northern India.”

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