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| Shreekant Sambrani: Follies & IMD - Siamese twins | | There seem to be no observable criteria to identify monsoon showers |
| Shreekant Sambrani / Jul 05, 2009, 00:51 IST |
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There seem to be no observable criteria to identify monsoon showers.
A Marathi saying goes, “And the rainy season regularly follows (the summer).” That may not have been much in evidence this year in India, but the hardy annuals associated with the rainy season and the Indian Meteorological Department’s (IMD’s) obsession with forecasts of average rainfall, which serves little purpose, and its penchant for getting things right only after the fact, if ever at all, are very much with us.
IMD’s performance has been abysmal this year, even going by its execrable standards. It issued its now famous (notorious?) second forecast, revising the earlier one downwards — drastically so for the North-West — on June 25. The fact that only a day before its spokesperson had assured national TV audiences that there was nothing to worry about as the monsoon sometimes played truant after having set in, the forecast remained valid much in the manner of an indulgent grandfather talking about a lovable imp of a grandchild.
IMD went one better in flip-flops after the whole country started to worry whether the monsoon was ever going to arrive. It did what nature was loath to do: announcing the setting in of the monsoon at the first drop of a passing shower. However, when it did not rain after that, on June 29, IMD said though Delhi might get showers on July 1 or 2, the real onset of the monsoon was not likely before July 7. Nevertheless, when it rained in Delhi the following day, the met department pulled out all stops to herald the arrival of the monsoon. How could the Canutes of the land be kept waiting, even by nature’s vagaries?
There seem to be no objective, observable criteria to distinguish between pre-monsoon showers and the real thing. We have no choice but to take IMD’s word for it, even when it is, most likely, not worth the piece of paper on which it is printed.
For instance, the monsoon was to arrive in Pune — which houses the country’s premier observatory — on June 20, but the city was compelled to enforce a 30 per cent cut in water supplies 10 days after that date, because there was no rain!
In 2006, IMD said that the monsoon had entered Gujarat two weeks in advance on May 31 on the basis of what turned out to be the sole shower for the next five weeks to follow! It seems, IMD’s monsoon behaves like the storied bada babu of any Calcutta office of yore, arriving at the start of the office time, draping his jacket on his chair as proof of his presence and then disappearing for the rest of the day, goodness knows where!
Jim Andrews, the South Asia specialist of the well-known AccuWeather website, said in his blog on June 29: “What a difference a week makes. The South-West Monsoon, as reckoned by the India Meteorological Department, has leapt northwestward by hundreds of kilometres within the last week. Thus, the leading edge of the SW Monsoon has returned to near normal after having lagged well behind in time and place… It would be hard, though, to overstate the distinction between the South-West Monsoon and the rain it breeds. Normal onset/advance need not imply normal rainfall, for the details of atmospheric behaviour under the setting of monsoon are critical.” Being polite, he does not join all the dots, but then he does not have to. These inexplicable sudden twists and turns in the predictions and announcements of IMD are ample evidence to suggest that they do not all add up, really.
IMD now appears to be the cheerleader-in-chief, trying to allay our well-founded fears. There is no harm in saying some soothing words, but those words should not be uttered at the expense of scientific veracity. IMD has been quite opaque in its pronouncements, leaving one to wonder whether it is being led by the powers that be to spread the good word, consequences be damned. We do not know, for example, what has prompted it to change what it termed as pre-monsoon showers to regular monsoon in just one day. We are also at a loss as to why, when the monsoon is supposed to have set in most parts of the country, there are only stray passing showers everywhere; even the West Coast locations such as Ratnagiri, Mahabaleshwar and Mumbai have not had a major torrential shower so far, which is the norm for late June. Why again has the forecast for the North-West, which is now supposed to receive only 81 per cent of the normal precipitation, dropped off so drastically within a space of mere two months?
What is wrong with our weather forecasts? First, and the most important, as I have pointed out in these columns (IMD and its Pastcasts, BS, April 30, 2007) and elsewhere earlier, IMD’s season-long forecasts are of little value to farmers or those supplying water to cities. Above average rain concentrated in a few days results in a run-off, causing droughts in its wake, while even lower than average rain spread over many days leads to bumper harvests. What matters is not the quantum by itself, but its spatial and temporal distribution. IMD has made a little progress since then; it now has four regional forecasts and this year, month-wise forecasts for the country as a whole. This level of disaggregation, unfortunately, is far too non-specific for a continental country critically dependent on monsoon precipitation.
These season-long forecasts themselves are based on associative, not causative relationships. They are a bit like the graphic analysis the so-called technical specialists of the stock market do — comparing trends of variables that seem to move together, not necessarily because there is an established cause-and-effect relationship between them. Such technical analysis perhaps helps punters, but not serious business economists. The IMD forecasts are not much different.
IMD’s near-obsession with season-long forecasts and with ensuring that there are minimal departures of the date of actual onset of monsoon from the expected one have resulted in it not paying sufficient attention to some other determinants of the weather, which are far more important than the models so dear to it. Some of these, which have a crucial bearing on the current situation, are the subject of a companion piece.
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