Impact Assessment of Climate Change on Rainfall over a Small Catchmen

A methodology is presentedfor the stochastic generation ofdaily rainfall which accountsfor changes to the climatic inputs. the focus of the study is an example catchment in iran. themethodology addresses the inability ofgcms to provide suitable future scenarios for the time andspace scales requiredfor a water resource impact assessmentfor a small catchment. one stochasticmodel for rainfall (neyman-scott rectangular pulses, nsrp, model) is used to generate dailyrainfall sequences and then validated using historic records. for present climate conditions, thensrp model is fitted to observed rainfall statistics. gcm outputs are then downscaled usingregressions between atmospheric circulation indices (acis) and rainfall statistics. therelationships are then used to predict the rainfall statistics for future conditions using gcmoutputs.in this respect, climate change impacts are studied and assessed in this paper. generated rainfallscenario can then be used as inputs to a rainfall-runoffmodel in order to generate daily streamflowdata which is not investigated here.