Evaluation of the global rainfall datasets for use in physical models, Case study: Karoun Basin

Due to the lack of proper spatio-temporal coverage of precipitation measuring stations in the country, there is a need for gridded data with proper spatial and temporal resolution. For this reason, global rainfall centers were used in water resources studies. In recent years, the number of these gridded datasets has been increasing and many of these datasets have been used in water resources studies. In this research, rainfall datasets have been evaluated in both pixel scale and mean basin with observation data in the Karoon basin. The datasets used in this study are PERSIANN, PERSIANN-CDR, APHRODITE, TRMM-3B42 RT, CHIRPS V2.0, ERRA-INTERIM. Evaluations were made on a daily scale and for the period of 2003-2013. According to the results of statistical indices such as coefficient of determination and NRMSE, the APHRODITE and ERRA-INTERIM datasets have shown better performance than others. Also, according to the contingency table indicators, the APHRODITE and ERRA-INTERIM datasets have good performance. The results showed that despite the fact that the APHRODITE and ERRA-INTERIM datasets have the proper accuracy in all evaluations, they have poor performance in detecting non-occurrence of rainfall. According to the evaluations, the APHRODITE dataset can be used as an alternative to observational data and among satellite datasets, Among the satellite datasets, TRMM has better performance, and with calibration and bias correction using observational data, this satellite can be used in water resources studies for the target area.