Changing Characteristics of Droughts over Kerala, India: Inter-Annual Variability and Trend

Realized changes in the climate over Kerala received more attention during recent times under the back to back drought conditions prevailing over the state. The year 2016 registered as one of the worst and extreme drought year over Kerala in recent past. This extreme drought condition may be attributed to the combined effect of realized changes in the mean climate state as well as the climate variability.Both the recent and historic drought events over Kerala is examined and its possible impacts on different sectors like agriculture and water resource are studied using the standardized precipitation index (SPI). Historical occurrence of both the short term and long term water stress associated with deficit rainfall during monsoon and post-monsoon season is presented in the paper. It is found that south west monsoon rainfall over Kerala is decreasing over south Kerala during recent decades, whereas the post-monsoon rainfall is found to be increasing especially over south Kerala. There exists a weak relationship between Pacific SST and Kerala rainfall. Trend analysis of SPI on different time scale showed negative trend and that negative trend increases with increasing time scale.