The Xinanjiang model contained 15 parameters in total, which are listed in Table 1. Each represents the properties of the catchment. Although some insensitive parameters can be obtained from the observed information, the sensitive parameters must be calibrated (Thiemann et al. 2001). The range of each parameter is listed in Table 1, which is used for the calibration of the model's parameters.
Parameter ranges used in the simulations for the XAJ model
| Parameter . | Description . | Range . |
|---|---|---|
| WM | Areal mean tension water storage capacity: WM = WUM + WLM + WDM | 100–150 |
| X | WUM = X*WM, WUM is the upper layer tension water storage capacity | 0.1–0.6 |
| Y | WLM = Y*(WM-WUM), WLM is the lower layer tension water storage capacity | 0.1–0.6 |
| KE | Ratio of potential evapotranspiration to pan evaporation | 0.6–1.2 |
| B | Tension water distribution index | 0.1–1.2 |
| SM | Areal mean free water storage capacity | 20–70 |
| EX | Free water distribution index | 0.1–1.2 |
| KI | Out flow coefficient of free water storage to interflow | 0.8–0.99 |
| KG | Out flow coefficient of free water storage to groundwater flow | 0.95–1 |
| IMP | Impermeable coefficient | 0.01–0.1 |
| C | Deep layer evapotranspiration coefficient | 0.15–0.2 |
| CI | Interflow recession coefficient | 0.01–0.1 |
| CG | Groundwater recession coefficient | 0.03–0.15 |
| N | Parameter of Nash unit hydrograph | 1.0–10 |
| NK | Parameter of Nash unit hydrograph | 5–15 |
| Parameter . | Description . | Range . |
|---|---|---|
| WM | Areal mean tension water storage capacity: WM = WUM + WLM + WDM | 100–150 |
| X | WUM = X*WM, WUM is the upper layer tension water storage capacity | 0.1–0.6 |
| Y | WLM = Y*(WM-WUM), WLM is the lower layer tension water storage capacity | 0.1–0.6 |
| KE | Ratio of potential evapotranspiration to pan evaporation | 0.6–1.2 |
| B | Tension water distribution index | 0.1–1.2 |
| SM | Areal mean free water storage capacity | 20–70 |
| EX | Free water distribution index | 0.1–1.2 |
| KI | Out flow coefficient of free water storage to interflow | 0.8–0.99 |
| KG | Out flow coefficient of free water storage to groundwater flow | 0.95–1 |
| IMP | Impermeable coefficient | 0.01–0.1 |
| C | Deep layer evapotranspiration coefficient | 0.15–0.2 |
| CI | Interflow recession coefficient | 0.01–0.1 |
| CG | Groundwater recession coefficient | 0.03–0.15 |
| N | Parameter of Nash unit hydrograph | 1.0–10 |
| NK | Parameter of Nash unit hydrograph | 5–15 |