E-Paper
West Bengal witnesses huge disparity in monsoon rain distribution
While Asansol in West Burdwan district received 434.5mm rain between Wednesday and Thursday morning
At least two places in south Bengal – Asansol in West Burdwan and Bankura – received the highest ever rainfall in one day, even as officials from the meteorological department pointed out the huge disparity in the distribution of monsoon rain in the state since June.
While Asansol in West Burdwan district received 434.5mm rain between Wednesday and Thursday morning, Bankura district recorded 354.3mm rain during the same time. Bankura received more than 30 times excess rain on a single day.
“This is the highest rain the two places have received in any month till date. While the previous high in Bankura was recorded in June 1922 when it received 292.4mm rain, the previous high in Asansol was recorded in July 2018 when it received 192mm rain,” said an IMD official.
Even though Cyclone Gulab, which hit the Andhra Pradesh coast on September 26, didn’t have much effect in West Bengal, a cyclonic circulation that intensified into a well-marked low-pressure system, triggered heavy rain in Kolkata and other districts of south Bengal this week.
Last week, Kolkata received the heaviest September rain in 14 years. Large parts of the city have been inundated. At least 14 persons were electrocuted to death across the state in waterlogged streets and houses.
“The disparity is because monsoon has been vigorous of late in south Bengal. Back-to-back cyclonic circulations are developing over the Bay of Bengal, which on intensifying and approaching the coast, are triggering intense spells of rain,” said a senior official from the meteorological department.
Even though south Bengal has been receiving heavy rain over the past few weeks, officials pointed out a huge disparity in the cumulative monsoon rain the state has received this season since June.
While at least nine districts in West Bengal, including Kolkata, have received excess rain, seven districts received normal rain. Three districts – Malda, South Dinajpur and North Dinajpur received deficient rain.
According to meteorological parlance, rainfall is considered ‘normal’ if the amount is 19% below or above the climatic normal of three decades. In case it is 20% to 59% more, it is called ‘excess’ rain. Likewise, a shortfall of -20% to -59% is said to be ‘deficient’.
“One of the primary reasons behind these intense spells is climate change. The water holding capacity of the atmosphere increases by around 7% if there is a rise of one degree in temperature. Across India, incidents of heavy rain spells are increasing. This is just one consequence of climate change,” said KJ Ramesh, former director of the India Meteorological Department.
Data available with the Union ministry of earth sciences reveal that while in 2016 around 1864 IMD stations across India recorded very heavy rain and 226 stations recorded extremely heavy rain, in 2020 at least 1912 stations had registered very heavy rain and extremely heavy rain was recorded in 341 stations. In 2018 and 2019 such events were even higher.
The ‘Assessment of climate change over the Indian region’ – a report published by the Union earth sciences ministry in 2020 suggests that there has been a shift in the recent period toward more frequent dry spells and more intense wet spells during the summer monsoon season. The frequency of localized heavy precipitation occurrences has increased worldwide in response to increased atmospheric moisture content
“Our analysis of 100 years of data of rainfall in West Bengal shows that the overall rainfall in the monsoon season has increased but the number of rainy days has dropped resulting in intense spells. What aggravates the situation is that while on one hand alteration of nature is going on in an unbridled way, we also lack the mitigation and preparedness,” said Tuhin Ghosh, director of the School of Oceanographic Studies at Jadavpur University in Kolkata.
