TR(BR)-10/99-2000 : Drought characterization in arid and semi-arid climatic regions of India

Abstract

Prediction of regional drought characteristics forms a major concern in the planning of drought management strategies in drought prone areas in India. This study attempts to characterize droughts (frequency, intensity and duration) in and and semi-arid regions of the country using two readily available climatic parameters: (i) ratio of mean annual precipitation (Pa) to global terrestrial mean annual precipitation (Ps), and (ii) ratio of mean annual potential evapotranspiration (Er) to mean annual precipitation (Pa). Average return period (yr) is found to increase gradually from arid to semiarid regions. The return period varies from two to three years in the arid regions (12> Ep/Pa 5) and three to five years in semi-arid regions (5>Ep/Pa ?_2). Furthermore, relationships describing the probability of occurrence of moderate, severe, and extreme intensity droughts, defined in terms of the magnitude of annual deficit, are developed. The semiarid and arid climatic regions of the country are found more susceptible to suffer from relatively more intense droughts than the humid and sub humid regions.