Monsoon heads to normal, but with patches of drought: IMD

Total rainfall during the southwest monsoon is likely to be normal this year, according to the India Meteorological Department, although there is a meteorological drought over parts of Gangetic West Bengal, Jharkhand, Uttar Pradesh and the northeastern states.

“We can say that there are drought-like conditions over several parts of the Indo-Gangetic plains based on rainfall, temperature and aridity data that are monitored through standard precipitation index and aridity anomaly,” said Pulak Guhathakurta, head of the climate division in IMD Pune.

The weather department doesn’t not declare drought, but monitors indices that help track it. An analysis by the bureau showed that between June 1 and August 31, there were dry conditions over the region between western Uttar Pradesh up to Gangetic West Bengal. Dry conditions have also been seen over parts of Delhi, Haryana and Punjab. Several districts in northeast India are also showing drought conditions.

Also read: Widespread rainfall over northeast India for next 4-5 days: IMD

In the week to August 31, severely arid conditions were recorded over entire northwest India, Uttar Pradesh, Bihar, Jharkhand and Gangetic West Bengal.

So far, rainfall has been 105% of the long-period average since June 1, in line with the weather office’s forecast on April 31. On Thursday, it predicted above normal monsoon in September at 109% of the average.

“So far, we have received 6% excess rain and this may go up further, so we will have a good monsoon this year,” said M Mohapatra, director general of IMD. “It is not the first time that certain areas are experiencing very dry conditions, while there is excess or normal monsoon in other parts.”

Output from the kharif cropping season, which accounts for nearly half of the country’s annual food supply, is likely to be average, with the area sown countrywide lagging last year’s levels by around 1.5%, HT reported on Sunday. The area under paddy grown in the Gangetic plains states affected by severe arid conditions this year was 5.6% lower than last year’s.

“Extreme rainfall deficit over Uttar Pradesh, Bihar, Jharkhand, West Bengal, and other parts of the Indo-Gangetic plain has caused agricultural droughts in the region. Soil moisture deficit and agricultural drought has affected agricultural activities and the kharif crop,” said Vimal Mishra, professor of civil Engineering at Indian Institute of Technology, Gandhinagar, who has developed the India drought monitor.

From June 1 to September 3, there is 5% excess rainfall over the country, with 28% excess over south peninsula; 17% excess over central India; 2% excess over northwest India; and 19% deficiency over east and northeast India, according to the IMD. Uttar Pradesh has 44% rain deficiency; Bihar has recorded 37% deficiency; Jharkhand 26% and Gangetic West Bengal 29% deficiency. In July, eastern and northeastern India had recorded 44.7% deficiency, while in August, they recorded 26.5% deficiency.

“Several regions during this monsoon witnessed surplus rainfall and floods. Both drought and floods affected different parts of the country,” said Mishra. “Variability of rainfall extremes need to be incorporated in the declaration so that we can understand the impacts caused by the extremes.”

Mishra’s team along with researchers from UFZ-Helmholtz Centre for Environmental Research in Leipzig, Germany, published a research paper in IOP Science journal on August 24 that said the IMD ignores the role of spatial and temporal variability of rainfall while declaring whether the monsoon has been normal or not.

“Dry and wet extremes within the same monsoon season can lead to a normal monsoon. Moreover, different parts of the country face drought and wet extremes, while the summer monsoon can be declared normal,” the paper said. “Considering the profound implications of dry and wet extremes on agricultural activities, we propose a novel framework to account for the rainfall variability in the declaration of the summer monsoon.”

In the past 121 years since 1901, 84 years were declared to be normal or above normal monsoon years. However, 13 years out of 84 were not normal based on the new framework suggested by the researchers due to dry and wet extremes occurring at different times and in different regions.

Also read: IMD sounds alert for Odisha, Uttarakhand; ‘heavy rainfall spell’ in these states

Some 1,000 people lost their lives due to extreme rainfall, floods and damage to agriculture in 2017, which was declared to be a normal monsoon year, the researchers found. Similarly, around 2,051 people died due to floods and heavy rain during the summer monsoon in 2005. Gujarat and Maharashtra were the worst affected. But the summer monsoon was declared normal, with a surplus rainfall of 9.6%, they found. Parts of the northeast also experienced moderate to severe drought during the 2005 monsoon.

There is likely to be subdued rainfall over northwest and central India over the next five days, IMD said. The western end of monsoon trough is lying along the Himalayan foothills and the eastern end is running north of its normal position. The eastern end is likely to shift southward from September 5 onwards. A cyclonic circulation is lying over Lakshadweep and adjoining southeast Arabian Sea.

Under the influence of these systems, widespread rainfall with isolated heavy rain is likely over Arunachal Pradesh, Assam, Meghalaya, Nagaland, Manipur, Mizoram and Tripura in the next four days. Thundershowers are also likely over Bihar and sub-Himalayan West Bengal till Monday, the weather bureau said.