India receives nine per cent less rainfall this year during the southwest monsoon between June and September. More than normal rainfall was recorded in just one state, while eight states have received less than average rainfall during this period. According to the report released by Ministry of Earth Sciences, the reason cited is the large and rare rainfall deficiency of 24 per cent recorded in northeast India.
The percentage departure of realised rainfall is considered below normal if it is less than 10 per cent for the Long Period Average (LPA) during the four-month monsoon season. The northeastern states of Arunachal Pradesh, Meghalaya, Manipur and Tripura recorded a deficient rainfall of 31 per cent, 40 per cent, 58 per cent and 21 per cent, respectively during the LPA, says the data.
However, northwest, central and south India received rainfall as predicted by the Indian Meteorological Department (IMD) with only marginal deficiency of 2 per cent, 7 per cent and 2 per cent, respectively. Actual rainfall received all over India is 793.5 mm, which is 76.5 mm less than the average 870 mm.
The report mentions large variations observed in 2018, with intense rainfall events that led to the floods in Kerala. During the LPA, an excess of 24 per cent rainfall was recorded in Kerala. As per the IMD data, Kerala received 2,346.6 mm of rainfall from June 1 to August 19, in contrast to an expected 1,649.5 mm of rainfall, about 42 per cent above normal. Between August 1 and August 19, the amount of rainfall recorded was 164 per cent above normal.
EnviStats India 2018, another report published by the Ministry of Statistics and Programme Implementation, says that rainfall in India is the major source of water and is dependent on the southwest and northeast monsoons. The deficiency is a cause of concern, since monsoon rain is the main source of groundwater recharge that makes up 67 per cent of total replenishable resource.
National Weather Forecasting Centre in its bulletin on October 3 has notified that a low pressure area is very likely to form over southeast Arabian Sea on October 5 and may intensify into a cyclone. It has advised fishermen not to venture into southeast and central Arabian Sea from October 6 onwards.
