Assessment of Satellite and Reanalysis Precipitation Products for Rainfall-Runoff Modelling in a Mountainous Basin

Precipitation, one of the key components of the hydrologic cycle varying over time and space and traditionally measured by rain gauges located above ground level which is the only way to have a direct physical estimate of precipitation where its data accuracy depends to the stations density to cover the spatiotemporal variation of precipitation properly. Meanwhile, precipitation measurement over complex topography and high land regions such as eastern part of Turkey has always been a great challenge in the recent decades. On the other side, satellite-based and numerical weather precipitation models output can be an alternative to fill this gap. Hence, the goal of this study is to evaluate the spatiotemporal stability and hydrologic utility of four precipitation products (ERA5, IMERGHHFv06, TMPA-3b42v7and PERSIANN) over Karasu river basin which is located in the eastern part of the country. Moreover, Kling Gupta Efficiency (KGE) including its correlation, bias and variability ratio components was used for direct comparison of precipitation products (PPs) with observed precipitation and the Hansen-Kuipers score (HK) has been used to assess the detectability strength of PPs for different precipitation events. In the same way, the hydrologic utility of PPs was tested by using a conceptual rainfall-runoff model under Kling Gupta Efficiency (KGE) and Nash-Sutcliffe Efficiency (NSE) metrics. Generally, all PPs show low performance for the direct comparison with observed data while their performance drastically increases for streamflow simulation. TMPA-3b42v7 is able to predict streamflow close to observed discharge with the KGE performance 0.84 while IMERGHHFv06 comes with the second-best performance (KGE; 0.76). Likewise, ERA5 present a close performance to IMERGHHFv6 and well reproduce streamflow comparing to PERSIANN for the entire period (2015-2019) in this study.