Dry Facts

FACT ONE: The monsoons have failed. Everyone agrees on this one. The country is on the verge of the worst-ever drought, since rainfall has been nearly 35 per cent less than normal.

FACT TWO: The Indian Meteorology Department has been proven horribly wrong: Earlier this year, it had announced to the world that India would have its 14th consecutive normal monsoon.

If the Met department is to be believed, these are the only facts that can be taken for granted; the rest is uncertainty.

So what makes the Indian monsoon so mysterious? Why can8217;t the most advanced forecasting techniques predict the weather? So much so that when the monsoons decide to skip large swathes of the country, nobody really knows why?

That is not to imply our knowledge hasn8217;t grown much from the time the phrase 8216;monsoon8217; was coined by Arab mariners in reference to the seasonal winds in the Indian Ocean. We know the monsoons are found in Australia and West Africa as well, though nowhere is it more dramatic or more vital to the economy.

We also know how the monsoons are supposed to work. Moisture-bearing winds are attracted to the summer-roasted Indian landmass from the cold Indian Ocean. Once the winds cross the equator, they turn in the South-Westerly direction and shed their load over the heated peninsula, bringing rain. So far, even a Class V geography student could tell you.

What happens after this, however, is more complex. The now-dry winds move to the Bay of Bengal, where a convection system 8212; essentially a low pressure area spread over at least a five sq km area 8212; forms, and pick up moisture again. Simultaneously, a monsoon trough, another large low pressure area extending from Rajasthan to West Bengal, forms over the landmass. Winds moving in a cyclonic motion over the Bay of Bengal are pulled towards this trough and turn eastwards, bringing rain to North and Central India.

So what went wrong this year? It8217;s tough to pin-point an answer, since day-to-day variations do not give any clues to the larger seasonal picture. 8216;8216;In real time, it is not possible to arrive at conclusions,8217;8217; says K Rupa Kumar, scientist with the Indian Institute of Tropical Meteorology.

Scientists call it 8216;8216;a peculiar phenomenon8217;8217;, something which they have not seen in the past. 8216;8216;A break situation has occurred even before the monsoon could develop fully,8217;8217; says Rupa Kumar. The break normally happens after the monsoon is well in progress.

In layman8217;s language, it means that the two low pressure areas over the Bay of Bengal and the Indian landmass weaken even before they begin to form. The result: drizzles, not deluges.

Theories abound over why this has happened:

1 El Nino The correlation between the warm ocean currents off the South American coast and India is not very clear, but the El Nino may be responsible for the shift in the convection areas over the Bay of Bengal. Across the globe, the El Nino, and the consequent warming of the ocean currents, has affected ocean currents, leading to major shifts in weather patterns.

Of late, a number of foreign agencies have issued advisories on the revival of the El Nino, but Rupa Kumar is reluctant to lay the blame of the monsoon failure at its door. 8216;8216;The impact of the El Nino was felt months after it was detected off the Peru coast. It8217;s too early for it too impact us now,8217;8217; he says. As a result, the IMD did not include the El Nino as one of the parameters for the monsoon forecast.

2 Western Pacific systems Remnants of atmospheric systems over the Western Pacific normally enter Bay of Bengal, strengthening existing systems. Possibly this did not happen this year as there was no Westerly movement. The absence of the outside-help factor is one the Met department is seriously exploring to explain the failure of the monsoons.

3 Global Warming In spite of international reports and UN warnings, Indian scientists deny the role of global warming. 8216;8216;It can only be measured on a decadal scale, seasonal variations cannot be attributed to it,8217;8217; says Rupa Kumar. Also, scientists believe global warming would actually bolster the monsoon, not dry it up.

4 Low Pressure Trough The vital monsoon trough over the Indian landmass never formed this year. Normally, this area floats over the subcontinent and dips into the Bay of Bengal, kickstarting the monsoon rains.

Abnormal development of the south-bound track of the westerly system over Pakistan could have disrupted its formation. This is a likely reason for the failure of the monsoons.

5 Localised Patterns The right quantums of moisture, temperature and solar radiation over the Bay of Bengal help the monsoon to develop. One disproportionate factor could have led to the dry monsoon phenomenon on the subcontinent.

Even as they study these possibilities, Met officials are keeping their fingers crossed that the monsoon will get revived by the middle of August. 8216;8216;As long as there are clouds over the Bay of Bengal, there is hope,8217;8217; says a Met scientist.