Unmasking the monsoon
Putting together the finer pieces of the monsoon puzzle remains a challenge as new key drivers have emerged
But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand.” This charming piece of dry British wit from the pen of Jerome K Jerome mocks the weather-obsessed Brit, and it may even amuse urban Indians, who every scorching summer, submit themselves to the tantalising tease of the monsoon rains. But for the millions of poor Indian farmers, whose lives depend on not only generous but also timely rains,Jerome’s wit might appear a tad too blithe, even rude. The recent ill-timed hailstorms that decimated crops of thousands of unsuspecting farmers in north and west India underscore the absolute importance of foreknowledge. If truth about the monsoon could be foretold, the Indian farmer would be certainly better off.
So come April every year, India’s official weather tracker, aka the India Meteorological Department (imd), goes into a tizzy trying to anticipate—with the help of reams of weather data, complex mathematical models and brute computing power, not to mention a bit of gambler’s gumption,fortified by a sense of history—whether the monsoon is going to be normal,generous or miserly.
A seasonal or long-range forecast (lrf ), as it is commonly called, only gives the odds for the quantum of total rainfall from June to September.Albeit of no practical use to an individual farmer’s sowing decisions, it is, nonetheless, a portent of hope, or possible gloom,for the national gdp and the agrarian economy.
imd provides lrf for the Indian monsoon rainfall in two stages—first,in the third week of April,and then in the second week of June.Along with these,imd also issues monthly forecasts for July and August for the country as a whole.
Conventionally,lrf is made using statistical models, which harness historical data to ascertain Indian monsoon’s relationship with a host of atmospheric
ILLUSTRATIONS: SORIT / CSE