- India Meteorological Department (IMD) has decided to drop the word “draught” and replace it with "deficient" to describe a bad monsoon.
- New criteria is based on the rainfall and its distribution across the country in a season, it will only declare a "deficient" or "largely deficient year".
- The India Meteorological Department has changed the languages used in weather forecasting so that the civil administration gets a more realistic sense of the upcoming weather events.
- IMD earlier used to term a year as one of drought whenever rain deficiency was more than 10 per cent. When 20-40 per cent of the country faced drought, it was termed an all-India drought year. When spatial coverage of drought was more than 40 per cent, it was termed an All-India Severe Drought Year.
- The new criteria classify all-India rainfall into five categories: a) normal (plus or minus 10% of the long period average); b) below normal (rainfall lower than 10% below average); c) above normal (rainfall greater than 10% above average); d) deficient year (rainfall deficit between 10 and 20% up to 40% of India’s spatial area) and e) large deficient year (rainfall deficit of over 10% across more than 40% of India’s area).
- The rules also change criteria to classify seasonal rainfall. Instead of the old four rainfall categories (excess, normal, deficient, and scanty), the IMD has introduced six categories – a) Large excess: 60% and above; b) excess: between 20% and 59%; c) normal: minus 19% to plus 19%; d) deficient: minus 20% to minus 59%; e) large deficient: below 60%; and no rain:
- The new language adopted by IMD will mean 2015 was actually a “Deficient Year”.
- There are some changes in terminology for rainfall, snowfall, heat wave, cold wave and city as well as tourist spot specific weather forecast for short, medium and long term.
- Following are the key terms that have now been standardized by the IMD:
1. Heat wave: Temperatures greater than 4.5 degree Celsius above what’s usual for the region.
2 .Cold wave: Temperatures less than 4.5 degree Celsius above what’s usual for the region.
3. Severe heat wave: greater than or equal to 47 degree Celsius.
4. Severe cold wave: Minimum temperature is 2 degree Celsius or lower.
- There are several types of drought and no uniform definition of the term. There is meteorological drought, hydrological drought and even a socio-economic drought. So, there was a need for more uniform definition of draught.
- Over recent years, Numerical Weather Prediction models have improved IMD’s ability to predict weather and rainfall across various regions. Forecasters also have better access to Doppler Weather Radar, satellite and other data to help with decision-making.
- Forecasters have to take advantage of all these developments and improvements so that more useful information is included in the forecasts with more clarity.
- The decision by the India Meteorological Department ( IMD) to stop using the term “ drought” makes sense. The weather office is, at best, qualified to pronounce a meteorological drought, taking into account the deficiency of rainfall and the extent of area affected by it. It cannot take acall on agricultural or hydrological droughts, which are determined by considerations beyond rainfall levels.
- For India, agricultural drought is what matters the most as it can affect crop production, farm incomes and rural demand. However, the noteworthy point is that the extent of deficiency in rainfall which causes withering of crop plants and, hence, drought in one region may not necessarily do so in another, where the irrigation facilities are well developed.
- The north- western grain bowl of Punjab, Haryana and western Uttar Pradesh, where over 90 per cent of the crop land is irrigated, is a case in point. The region saw only a marginal reduction in farm harvests despite recording a rainfall deficit of 21 per cent in 2014 and 17 per cent in 2015.
- Moreover, the effect of the agricultural drought and the strategies needed to cope with it depends largely on the timing of the moisture stress — whether it is in the early part of the crop season or in the middle or end of it.
- Since it is the local administration and the state governments which are obliged to take the necessary remedial actions, it is better to leave the declaration of drought to their judgement.