Studies on the influence of El-Nino on rainfall in eastern Uttar Pradesh

Abstract

Increase in rainfall means a bumper crop production and erratic monsoon means a bad production of crops resulting into the loss of country's economy. The average rainfall for the El Nino years (strong and moderate El Nino) was compared with the normal rainfall for the years 1981 to 2016 during the four different seasons. The percentage change in seasonal rainfall during the El Nino years compared to normal rainfall was also computed for the seasons in different districts. Results revealed that the average rainfall during the S-W monsoon season during the El Nino years was less than the normal rainfall in all the district of Eastern UP. The departure was maximum in Barabanki district by 9.0 percent and lowest departure (0.4%) was recorded in Jaunpur districts. The average summer season rainfall during El Nino years from March to May was less than the normal rainfall in Eastern U.P. Maximum departure (20.3 percent) was recorded in Gorakhpur district and minimum departure (0.2%) over normal rainfall was recorded in Ballia district. The average rainfall during winter season during El Nino years from January to February was less than the normal rainfall in all the districts of Eastern U.P., The maximum departure (17.5%) was recorded in Ghazipur district. The average rainfall during the post monsoon (October to December) during El Nino years was almost less than the normal rainfall in Eastern U.P. during the years with El Nino compared to normal rainfall. El Nino unambiguously serves as a signal of deficit rainfall for the Eastern U.P. during the south west monsoon season and if it does not happen, leads to deficit annual rainfall. Analysis of long term data suggests an inverse relationship between El Nino and SW monsoon rainfall. However, there is no one to one relationship as El Nino years have not always produced severe drought. The average annual rainfall or S-W monsoon season rainfall were less than normal rainfall during the years with El Nino.