Abstract:
There has been a considerable research on modelling of various aspects of drought such as identification and prediction of the duration and severity. The term severity has various connotations in drought literature such as in hydrological drought, it is defined as cumulative shortage or the deficit sum with reference to a pre-specified truncation level. Whereas in meteorological drought, the severity has rather been defined in the form of indices such as Palmer drought severity index, among others. There exist a variety of techniques and methods to analyse the duration and the severity of meteorological and hydrological droughts through probability characterization of low flows, time series methods, synthetic data generation, theory of runs, multiple regression, group theory, pattern recognition and neural network methods. Agricultural droughts are analysed based on soil moisture modelling concepts with crop yield considerations and using the multiple linear regression techniques. The prediction aspects of drought duration are reasonably well developed, whereas the drought severity aspects are yet to be refined because such information is not only of paramount importance but forms an essential and integral part of the design process of storage facilities to combat and abet droughts. A major challenge of drought research is to develop suitable methods and techniques for forecasting the onset and termination points of droughts. An equally challenging task is the dissemination of drought research results for practical usage and wider applications.
