The India Meteorological Department (IMD) will come out with a detailed scientific analysis of the 2018 monsoon season that led to over 9 per cent less rainfall. A preliminary scientific analysis reveals that the sea surface conditions over the equatorial Pacific (El Nino conditions) did not have any adverse effect on the performance of monsoon rainfall. The four-month-long southwest monsoon season officially ended on September 29. The IMD had forecast a normal monsoon but the rain fall deficiency is recorded 9.4 per cent this year. This is a second year in a row when monsoon ended with below normal rainfall.
On the other hand, the IMD on Monday attributed that 24 per cent shortfall of rains over northeast India, have led to deficient monsoon (9.4 per cent) this year, ended on September 30. During the period 1901-2017, only four years — 1992, 2005, 2009 and 2013, the rainfall deficiency over north east India was more than 20 per cent. Also, the northeast region, known for large scale floods, did not witness significant floods during the season.
According to IMD, due to day to day variability of rainfall has led to floods in several parts including Kerala, Himachal Pradesh and Uttrakhand. Despite deficiency, the kharif crop sowing is higher by 2.6 per cent this year as compared to the last year. Besides, the water reservoir levels stands at around 5 per cent higher than 10-year mean storages and 17 per cent higher than the storages of corresponding period during 2017.
“ If northeast region had received normal rainfall, the all-India rainfall would have been 96 per cent of the Long Period Average (LPA). However, over northwest India, central India and south Peninsula, seasonal rainfall distribution was satisfactory and well distributed as predicted, with only marginal rainfall deficiency of 2 per cent, 7 per cent and 2 per cent respectively,” the IMD said.
As per data, Manipur (-58 per cent), Lakshadweep (-48 per cent), Meghalaya (-40 per cent) and Arunachal Pradesh (-31 per cent) recorded the lowest rainfall till September 30. Every second state experiencing deficient rainfall is from the northeast.
IMD officials said that the season also witnessed formation of a large number of low pressure systems over Bay of Bengal and their westward movement across central India. During the season, 10 Low Pressure Areas formed, out of which one system intensified into a Cyclonic Storm, one into a Deep Depression and 4 into Depressions.
According to IMD, the resultant acreage is largely manifested by the good soil moisture distribution across the country. Adequate soil moisture available over northern parts of India may help the Rabi crops during 2018- 19. The cumulative rainfall across the country for the overall season between June 1 and September 30 was recorded at 804 millimetre (mm) against the normal rains of 887.5 mm, the report suggests. The overall rainfall was 84 mm fewer than normal. The month of June ended with a rainfall deficiency of 5 per cent, which increased to 6 per cent in July. In August, the rainfall deficit increased to 8 per cent. The deficiency increased to 22 per cent in September.