All’s well that ends well. So true for the south-west monsoon this year. Though the distribution of rainfall was skewed in both time and space, the belated surge in monsoon activity in September, when it should normally have been winding up, camouflaged these drawbacks to leave an overall positive impact. Till August-end, the cumulative monsoon rainfall was below normal. This deficit was made good in the last month of the four-month season (June to September). However, thanks to the September downpour, this year’s monsoon once again caused floods in several northern states, leaving the usual trail of destruction. But, on the upside, even the meteorologically sub-normal rainfall has, by and large, been adequate for crop sowing, generating optimism about kharif harvest. The heavy late-season downpour also helped recharge groundwater reserves and replenish surface water reservoirs that had been heavily depleted due to last year’s drought. All this is good news for the economy since the monsoons have ensured adequate water for crop irrigation, hydro-power generation, and normal drinking water needs.
The most baffling part of this year’s monsoon was that the eastern region, which is historically a high-rainfall zone, has remained rain-starved. The deficiency in rainfall in this region, which includes eastern Uttar Pradesh, Bihar, Jharkhand, Gangetic West Bengal and north-eastern states, was as high as minus 32 per cent at the end of August. The resurgence of monsoon activity in September slashed the deficit to minus 17 per cent by the end of the season. Only on four occasions in the past 110 years have the monsoons been worse than this in the eastern zone. Despite all these shortcomings, the overall two per cent surplus rainfall this year has given comfort to the economy. The India Meteorological Department (IMD) is satisfied that all this is in line with its own projected “long-range monsoon forecast update” issued on June 25!
Given its poor track record in long-range monsoon predictions, especially since the 16-parameteric statistical power regression monsoon prediction model (introduced in 1988) had been replaced with new models after its failure to forewarn of the 2002 drought, IMD is pleased.
This year’s improved forecast will, therefore, help partly redeem the IMD’s credibility though its methodology would still need to be revalidated in the next few seasons to be able to inspire confidence among public and policy planners. It is worth recalling that substantial investment has gone into upgrading the IMD’s data gathering and computing systems, particularly after the 2004 drought, which it could not foresee. Besides creating a dense infrastructure of satellite-based automatic rain gauge stations and facilities for upper air observations, an extensive network of Doppler radars has been put in place to ensure speedier collection, transmission and processing of weather-related information. It is now up to the IMD’s meteorologists to conceive relevant and reliable statistical models or, better still, dynamic models as are being employed by the developed countries, to put this infrastructure to good use. What this year’s floods remind us once again is the need for long-term measures for flood control. Monsoon-related floods are not entirely preventable, but easily manageable if there is adequate and imaginative human intervention.