Assessing the influence of water sampling strategy on the performance of tracer-aided hydrological modeling in a mountainous basin on the Tibetan Plateau

Abstract. Tracer-aided hydrological models integrating water isotope modules into the simulation of runoff generation are useful tools to reduce uncertainty modeling in cold basins that featured by complex processes and multiple components. However, there is little guidance on strategy field sampling for analysis run tracer-aided models, which especially important large mountainous Tibetan Plateau (TP) where work highly costly. This study conducted a set numerical experiments based THREW-T (Tsinghua Representative Elementary Watershed - version) model evaluate reliance performance availability site measurements Yarlung Tsangpo river (YTR) basin TP. Data conditions considered included glacier meltwater measurement, quantity precipitation isotope, variable collecting strategies stream samples. Our results suggested (1) high-mountain samples not available, estimating an offset parameter from feasible way force model. Using δ18O were 2 ‰–9 ‰ lower than mean resulted only small changes quantifications contributions components (CRCs, smaller 5 %) streamflow YTR basin. (2) The correct global gridded product isoGSM (isotope-incorporated spectral model) forcing should be carefully designed. Collecting at sites falling same altitude tends worse representing ground pattern over range altitudes. (3) weekly wet warm seasons optimal calibrating evaluating It recommended increase number rather spending resources extensive sole years. These provide implications isotopes running improve CRCs basins.