Impact of Spatial Resolution on River Flow Simulation Based on the Total Runoff Integrating Pathway (TRIP) Model

Although the impact of spatial resolution on river flow simulation has been examined in several studies, unresolved uncertainties remain regarding parameter sensitivity and the applicability of different routing models. This study investigated the resolution dependency of the total runoff integrating pathway (TRIP) river routing model while focusing on East Asia. With the increasing spatial resolution of Earth system models (ESMs), understanding the effects of resolution changes on river discharge characteristics is essential for conducting accurate hydrological simulations. In this study, we conducted sensitivity experiments using the TRIP model at resolutions of 0.5°, 1°, and 0.125° while considering idealized and real-case scenarios. The results indicate significant improvements in the representation of river networks and discharge dynamics at higher resolutions, highlighting the need for parameter adjustments, particularly with respect to flow velocity and meandering factors. Parameters were optimized based on matching the travel time of runoff from precipitation sources to river mouths. The optimized parameters yielded consistent river storage and discharge results across different resolutions, enhancing the reliability of high-resolution hydrological modeling. Our study highlights the importance of resolution-aware modeling in improving the simulations of hydrological processes in different climate systems. Notably, our study can serve as a foundation for future interdisciplinary studies on climate modeling, river discharge and flow simulations, and hydrogeology.