Simulation of Manas River runoff based on ERA5-Land dataset

Meteorological data is a key factor in hydrological process research, and the development of reanalysis data provides a new solution for runoff simulation in data-scarce regions. In order to study the applicability of ERA5-Land reanalysis dataset in local runoff simulation, several evaluation indexes were selected to evaluate the accuracy of ERA5-Land precipitation and temperature in the Manas River basin above the Kanswat hydrological station, and the distribution characteristics of the two ERA5-Land components in the study area were analyzed by empirical orthogonal function (EOF). In terms of accuracy, ERA5-Land has a good correlation with measurement data. The precipitation detection rate was 0.96, which can reflect most precipitation events, but was 21.81% higher than the measured rate. The accuracy of temperature was better comparably, with better overall fitting accuracy, yielding an optimal range of -5-20 ℃, with increasing uncertainties near the extremum. The EOF deterministic mode showed that the precipitation and temperature flutuations in the study area followed basically the same trend, that is, they were susceptible to the influence of large-scale weather system. In the validation period, the Nash coefficients (NSE) were 0.88 and 0.82 for the final SWAT runoff models at daily and monthly scales, respectively. The ERA5-Land reanalysis dataset can provide a reference for runoff simulation in northwest China where measured meteorological data are lacking. © 2022, Editorial Office of Earth Science Frontiers. All right reserved.