Application of satellite and reanalysis precipitation products for hydrological modeling in the data-scarce Porijõgi catchment, Estonia

Abstract

Study region: The Porijõgi catchment in Estonia, Northern Europe. Study focus: The lack of adequate precipitation gauges has long been a major obstacle for hydrological modeling. To date, the global availability of satellite and reanalysis precipitation (SRP) products at an increasingly high spatiotemporal resolution has made their use in hydrological applications possible. This study focuses on a comprehensive evaluation of the hydrological applicability of five SRP products. The evaluations were carried out in two parts: (1) evaluating the quality of satellite and reanalysis-based precipitation products relative to gauge observations, and (2) comparing gauge-simulated streamflow with SRP-based simulations using the SWAT model. New hydrological insights for the region: Our results show moderate variation in the detection capability of SRP products and in their influence on streamflow simulations. None of the products performed well with daily-scale predictions. The IMERG, ERA5, and PERSIANN-CDR products showed the best detection capability for the monthly precipitation and demonstrated reliable performance to simulate the monthly streamflow (0.65 < Nash–Sutcliffe efficiency coefficient < 0.75). However, the SM2RASC and CMORPH-CRT products tended to underestimate the gauged precipitation and provided unsatisfactory performance in streamflow simulation. Overall, our findings suggest that SRP products can be a priori alternative sources of precipitation data suitable for hydrological applications in poorly gauged areas.

Keywords

• Data scarcity
• Hydrological modeling
• Satellite precipitation
• Sensitivity analysis
• SWAT model