This section evaluates the selected

This section evaluates the selected six P products using the method of water budget closure residual, which considers fully HDPs, at monthly and seasonal scales. Fig. 3 is the results of monthly and seasonal average budget closure residuals of the six P products. They were calculated using the method in Eq. (4) based on different P products and the same merged additional budget fluxes (R, ET and TWSC). As described above, water budget closure residual, reflecting the closure degree of hydrological system, provides an important opportunity for evaluating and selecting P products in ungauged regions. In addition, being different from the commonly used statistical methods such as CC, RMSE, which has the shortage of data reuse as described above resulting in unreliable evaluation results, water budget closure-based method provides a different perspective to evaluate and compare the quality of P products.