Multiscale evolution of persistence of rainfall and streamflow

Hydrologic persistence plays an important role in natural mechanisms governing hydrologic processes and their interdependence. The spatio-temporal evolution of persistence in rainfall and streamflow and their joint behaviour is examined here through the estimation of Hurst Coefficient using Detrended Fluctuation Analysis (DFA) and Detrended Cross-Correlation Analysis (DCCA). The MOPEX (Model Parameter Estimation Project) watersheds in USA and the Cauvery River Basin in India are used as case studies. The analyses show that the temporal dynamics of the persistence of rainfall and streamflow and their joint behaviour are non-uniform across different time scales. It is found that the contribution of catchment processes influencing the persistence of the streamflow is a function of the catchment area. The state of persistence of joint behaviour is neither dependent on the rainfall amount nor affected by the changing patterns of dry and wet spells whereas the persistence of rainfall alone is affected by the latter.