Spatiotemporal Analysis of Drought Persistence of Peninsular India

Abstract

AbstractThe present study investigates the drought persistence of Peninsular India (PI) using a meteorological drought index. Standardized Precipitation Index (SPI) time series was computed for different aggregation time scales (1, 3, 6, 12, 24 and 48 months) using monthly rainfall data for the period 1871–2016 for the Peninsular region and six of its meteorological subdivisions. The Hurst exponent (H) values based on Rescaled range (R/S) method were estimated for monthly, annual and seasonal rainfall and different SPI time series of all the subdivisions and PI. Monthly rainfall data of PI and its subdivisions displayed short-term persistence while the SPI series derived from it showed long-term persistence. It was also observed that the persistence increases with the increase in the aggregation time scale. The persistence analysis performed for the annual series of individual months revealed that the datasets of the post-monsoon season are long-term persistent at the PI region and all of its subdivisions. The data of August month and monsoon season are found to be short-term persistent in the PI region and Kerala subdivision. Moreover, in order to capture the temporal change in persistence, the analysis was performed by partitioning the different SPI and rainfall series with respect to the global climatic shift of 1976/1977. There is no transition in the nature of persistence (short to long or vice versa) of drought index series and monthly rainfall series in PI and its subdivisions with respect to the climate shift.KeywordsDroughtPeninsular IndiaPersistence