Statistical assessment of satellite rainfall products in daily and monthly gauge spatial scales

Precipitation estimation is of great importance in energy balance calculations, hydrological studies, meteorology and agricultural, industrial, domestic and drinking purposes. Due to the importance of precipitation data in various sciences and the lack of an extensive and appropriate rainfall network, especially in mountainous catchments, it is necessary to estimate precipitation data and evaluate their accuracy. The purpose of this study is to evaluate the precipitation data of three IMERG satellite products of near real-time type, 3B42RT-7 of real-time type and PERSIANN-CDR of final-run type in the period of 06/01/2000 to 09/31/2018 in 41 rain gauge stations and three synoptic stations in and around the Neishabour Catchment area on a daily and monthly time scale. Examination of various statistical indicators showed that none of the three satellite products is a good representative of terrestrial data on a regional and daily scale. Therefore, the use of these products on a daily basis in this basin in hydrological models is not recommended. On the other hand, the monthly scale showed much better performance due to the adjustment of the error of estimating daily precipitation. So that, the correlation coefficient and Nash Sutcliffe coefficient of PERSIANN-CDR with monthly precipitation data in the basin are about 90% and 0.75, respectively, and the evaluation of this product is much better than the two products 3B42RT-7 and IMERG. Accordingly, the use of monthly scale precipitation products of the final-run type in water balance studies, especially in basins without statistics, can be considered.