Dynamical downscaling of ERA5-based high-resolution streamflow dataset over the Geum River basin, South Korea via VIC-river routing model (1950-2021)

The Geum River basin, located in the west-central part of the Korean Peninsula, is the third largest and minimally human-disturbed river basin in South Korea. Streamflow and available water resources from this basin is critical for water supply for agriculture. Due to the increased population, industrialization, and climate change, changes in streamflow and available water resources for the Geum River are expected. However, there are limitations in analyzing water resource changes in the Geum River Basin with discontinuous and relatively short observational streamflow records.

In this study, we propose to dynamically downscale daily surface and base runoff data from the 10-km ERA5 reanalysis product via VIC-River Routing model. The VIC-River Routing model was ran at the 90-meter spatial resolution with geographical information to reconstruct long-term naturalized streamflow data over 1950-2021. In the VIC-River Routing model, the flow direction, stream order, and slope estimated from the 90-meter digital elevation model (DEM) over Geum River basin as the topographical parameters. This downscaled natural streamflow data will provide an opportunity to investigate hydroclimatic changes of the hydrologic regime of Geum River.