## 4 Results
### Parameter Sensitivity
#### 4.1.1 Global Sensitivity  
The test-statistic (T-stat) was introduced by statistician [PERSON] in 1908 [29]. It is a valid statistical test that can be used to test whether the difference between two samples is significant. The \(p\)-value offers an alternative to traditional rejection thresholds, providing the smallest level of significance at which one would reject the null hypothesis. A smaller \(p\)-value indicates stronger evidence in favor of the alternative hypothesis. T-stat and \(p\)-value are employed as metrics to evaluate the sensitivity of model parameters. A widely held perspective is that a parameter exhibits greater sensitivity when its T-stat's absolute value is larger and its \(p\)-value approaches zero. In contrast, parameters are considered less sensitive if their T-stat's absolute value is smaller and their \(p\)-value is larger. The sensitivity ranking of each parameter during the calibration period provides guidance for the next calibration, and the parameters with high sensitivity become the primary target of the next adjustment. The range of parameters with high sensitivity is adjusted to see if the simulated values agree with the observed values. However, the adjustment of parameters with low sensitivity will have little or no effect on the change of the simulated value. After determining the parameter range during the calibration period, we used the same parameter range to simulate the runoff in the validation period. In this process, NSE and R\({}^{2}\) values were used to determine whether the simulated runoff was consistent with the observed runoff in the validation period [30; 31]. If the NSE and R\({}^{2}\) values do not meet the evaluation criteria (NSE > 0.5, R\({}^{2}\) > 0.5), the parameters with high sensitivity are adjusted again until the results for both the calibration and validation period are satisfactory. The statistical data presented in Table 2 outline the sensitivity ranking of parameters during the calibration period, along with their corresponding fitted values, range values, and properties. Presenting properties information for parameters allows readers with limited knowledge of hydrological models to more easily grasp the meaning of the parameters. Additionally, attribute descriptions for parameters facilitate the identification of their respective categories (such as groundwater, soil, hydrological response units, etc. ), thereby aiding in the comprehension of the hydrological processes within the watershed model. Parameters with T-stat absolute values exceeding 3 include soil moist bulk density (SOL_BD), baseflow alpha factor (ALPHA_BF), and baseflow distribution factor for sub-daily simulation (BFLO_DIST). Among these, soil moist bulk density emerges as the most influential parameter for hourly runoff simulation. A higher value of soil moist bulk density signifies an augmented likelihood of surface water percolating through the soil as lateral flow and groundwater, consequently curbing basin evaporation. BFLO_DIST, a parameter tailored for hourly simulations, represents an hourly scale baseflow distribution coefficient pivotal in governing baseflow values for such simulations. Its modulation mechanism dictates that a smaller value fosters a more even distribution of river baseflow within each hourly step over the course of a day, while a larger value introduces heightened variability. When the simulated baseflow value falls short of the observed value, appropriate adjustments to the BFLO_DIST parameter can effectively optimize simulated outcomes in alignment with the basin's actual characteristics. Sensitivity ranking serves as a valuable indicator for enhancing calibration efficiency. This is evident during the subsequent calibration process, where we prioritize parameters with high sensitivity and deemphasize the adjustment of parameters with low sensitivity. According to the findings presented in Table 2, we can conclude that certain parameters, like GW_DELAY, exhibit limited sensitivity to the simulation's impact.