TPRD3km: An observation-constrained high-resolution runoff data for Third Pole transboundary rivers

Rivers serve as vital freshwater resources and crucial carriers of sediment, organic carbon, etc. Calculating river runoff is essential for water resource planning, flood control, and ecological protection. However, in the high-mountain Third Pole (TP) region, characterized by extensive cryosphere coverage and harsh climate, in-situ runoff observations are extremely scarce, especially for transboundary rivers in southern TP. The complex runoff processes, strongly influenced by snow and glacier melt, pose significant challenges to hydrological modeling. Currently, long-term, high-resolution runoff datasets are still lacking in TP. Here, we employ an observation-constrained physically-based cryosphere-hydrological model, coupled with an energy-balance snow/glacier module, to simulate continuous daily runoff during the period 1981‒2020 over seven transboundary TP river basins. This model is calibrated using runoff observations near basin outlets and validated against daily records from 11 gauging stations. Results show that the model can effectively reproduce the daily streamflow dynamics over the study period in TP basins, with Nash-Sutcliffe efficiency (NSE) and correlation coefficients all exceeding 0.67 and 0.83, respectively, and absolute percentage bias (Pbias) within 18%. In addition, hourly-scale validations using discontinuous records yield satisfactory results, with NSE values exceeding 0.61 and absolute Pbias values within 9.5%. Furthermore, the snow and ice modules are validated using reliable remote sensing-derived snow cover and glacier area changes, showing good consistency. Based on the validated model, we generate a long-term 3-km, daily gridded runoff dataset and daily streamflow records for 11 cross-sections, which provide essential support for regional sustainable development and ecological conservation.