Impact of temporal rainfall resolution on daily streamflow simulations in a large-sized river basin

Compared to spatial resolution, few studies have investigated the impacts of temporal rainfall resolution on hydrological modelling. Respectively using 9 years of daily and hourly rainfall data at 24 stations, we have established daily and hourly rainfall Soil and Water Assessment Tool (SWAT) models in a large-sized river basin in East Central China. Our results suggest that temporal rainfall resolution could significantly affect SWAT daily streamflow simulation results, with the hourly rainfall model performing considerably better than the daily rainfall model. One possible reason is that the hourly rainfall model could more effectively capture the impacts of rainfall in previous days, especially those with heavy rainfall and longer rainfall hours. Meanwhile, its enhanced variable storage coefficient method may lead to better streamflow routing. Furthermore, comparison of simulation results across all sub-basins has revealed a distinct scale effect in the impact of temporal rainfall resolution on SWAT simulation performance.