GUWAHATI, Aug 27 - Even as the State continues to reel under one of the worst floods to have hit it in recent times, a curious trend of deficit rainfall, at the same time, has also been conspicuous, which, experts believe, has a lot to do with climate change.
Sources in the Agriculture Department told The Assam Tribune said that erratic rainfall and unpredictable monsoon behaviour had been an evident trend for the last eight to nine years or so, impacting crop production substantially.
�The climatic aberrations have been manifest both during flood-time and drought-like situations. Disturbingly, even when there has been overall normal rainfall during the crop season, the pattern and the distribution has been erratic. This had led to floods and drought-like situations during almost the same period,� sources said.
As per official rainfall data during the crop season since 2007 (for both khariff and rabi season), average rainfall has been deficient in 2009, 2011, 2013 and 2014, while it stayed normal in 2007, 2008, 2010, 2012 and 2015.
Another trend concerning annual precipitation has been that the rabi season (October to March) has witnessed more deficit rainfall than the khariff season (April to September). In fact, barring 2007 and 2008, all the years including 2015 recorded deficient rainfall. During the khariff season, the rainfall-deficit years had been 2009, 2011 and 2013.
Again, month-wise rainfall data during khariff season in 2015-16 shows excessive rainfall in the months of April and August, normal in May and June, and deficient in July and September.
For the 2015-16 rabi season, rainfall was deficient in October, November and February, while it was excess in December, and normal in January and March. Overall, it was a year of deficit rainfall for the rabi season, with actual rainfall being 196.5 mm against the normal of 294.8 mm. Overall, it was normal rainfall at 1,936.5 mm against the normal norm of 2001 mm.
The district-wise rainfall distribution pattern during the khariff season in 2015-16 shows deficient rainfall in one district (April), seven districts (May), eight districts (June), 20 districts (July), two districts (August) and 16 districts (September). It was scanty rainfall in two districts (July) and one (September), while excess rainfall was witnessed in 16 districts (April), six districts (May), nine districts (June), 15 districts (August) and two districts (September). Normal rainfall was recorded in nine districts (April), 13 districts (May), nine districts (June), four districts (July), eight districts (August) and seven districts (September).
For the rabi season during the same period, rainfall was deficient in nine districts (October), eight districts (November), four districts (December), seven districts (January), five districts (February) and 11 districts (March). Scanty rainfall occurred in 14 districts (October), seven districts (November), two districts (December), three districts (January), 11 districts (February) and one districts (March). Excess rainfall was recorded in one, five, 16, 12, , four, and seven districts in the months of October, November, December, January, February and March respectively. Two districts and three districts recorded no rainfall in November and February respectively.
In 2014, while the rainfall during the khariff season (April to September) was normal, it was scanty during the rabi season (October to March), resulting in overall deficient rainfall for the year (all seasons).