Factors responsible for consecutive deficit Indian monsoons during 2014 and 2015

Abstract

Increased frequency of droughts in the recent decade (2002, 2004, 2009, 2014, 2015 being drought years) and the severity of their impact makes drought prediction an inherent component of forecasts for drought mitigation and preparedness. The research and development activities cannot prove their full potential unless they can produce a long lead skillful prediction of extreme conditions like flood or drought. During 2014 and 2015, India experienced deficit monsoon for two successive years. The present study explores the various factors responsible for the droughts during 2014 and 2015 and how well the state-of-the-art coupled model capture the consecutive droughts. The study shows that not only tropical sea surface temperatures (SSTs) but also extratropical SSTs can influence the rainfall over India. Extratropical SSTs impacted the rainfall during 2014 by modulating the strength and location of subtropical jet and tropospheric temperature gradient. On the other hand, tropical SSTs over Pacific Ocean influenced the rainfall during 2015 by modulating the atmospheric teleconnections via Walker circulation. The present-day models considered in this study could not capture consecutively the Indian monsoon droughts and the associated atmosphere and ocean conditions.