Long-Term Meteorological Drought Characteristics in Southern India

Drought is a natural calamity, occurring due to less than average rainfall over a given period of time at given space which consequently leads to short-term water deficit and economic loss. The drought characteristics refer to frequency, severity i.e. magnitude of deficiency, and its duration. In this study long term monthly rainfall records for the period from 1901 to 2013 for all the 93 districts of central India covering the states of Andhra Pradesh, Telangana, Tamil Nadu, Karnataka, and Kerala has been used in the analysis. The percentage departures of annual and seasonal rainfall from corresponding average have been used for the identification of onset and termination, and quantification of severity of drought events. The study revealed that the average return period of drought in major part of southern India are in the order of 5–9 years except in the state of Kerala and coastal regions of Karnataka where the return period found to be more than 10 years. The central, north west, and south east part of the region faces the frequent drought of once in 5-6 years while the northern part and some parts of western Tamil Nadu experienced the drought with the return period of 7–9 years. There are only 3 districts (Chamrajanagar, Erode, and Coimbatore) where the average return period of drought is 4 years. The maximum rainfall deficiency in region had been found to be 66% of average annual rainfall for Nellore District which is rare. The coastal region experienced the maximum deficiency in the order of 30–45% of average annual rainfall i.e. severe drought are rare in the coastal region. The extreme drought events are very rare in the southern India. There have been numerous persistent drought events of 2-, and 3-, consecutive years found in the study. On the basis of this study various drought risk management in the Southern India can be applied.