Hydrological parameters are used to tailor simulation models to the specific characteristics of a catchment so that models can accurately represent processes under different catchment conditions. In the case of the mesoscale Hydrological Model (mHM), its parameters are estimated via transfer functions using the Multiscale Parameter Regionalization (MPR) approach. In this study, the spatial and temporal variability in the sensitivity of transfer function parameters (TFP) and their relationships to corresponding simulated processes are investigated to understand how these TFP control simulated hydrological fluxes and state variables. Daily dominant model parameters are identified for 102 German catchments as a study domain with temperate climate using a temporally resolved parameter sensitivity analysis. This approach allows the comparison of spatial and temporal variability of TFP dominance. Three simulated hydrological fluxes and one state variable are used as target variables for the sensitivity analysis: runoff, actual evapotranspiration, soil moisture (SM), and groundwater recharge. The analysis leads to consistent and plausible patterns of parameter dominance in space. An evapotranspiration parameter dominates actual evapotranspiration and SM. Runoff and recharge are mainly controlled by soil texture, subsurface, and percolation parameters. The relevance of spatial versus temporal variability varies among model parameters and target variables. In some cases, parameter sensitivities are related to the magnitude of corresponding processes. Low spatial and temporal variability of dominant parameters is explained by MPR. In light of these results, a joint spatio-temporal analysis is recommended to better understand how model parameters drive simulated states and fluxes in hydrological models to improve process accuracy.

中文翻译：

---

模拟水文通量和状态变量参数优势的时空一致性和变异性


水文参数用于根据流域的特定特征定制仿真模型，以便模型可以准确表示不同流域条件下的过程。在中尺度水文模型 （mHM） 的情况下，其参数是使用多尺度参数区域化 （MPR） 方法通过传递函数估计的。在这项研究中，研究了传递函数参数 （TFP） 敏感性的时空变化及其与相应模拟过程的关系，以了解这些 TFP 如何控制模拟的水文通量和状态变量。使用时间分辨参数敏感性分析，将 102 个德国集水区确定为温带气候的研究域的每日主要模型参数。这种方法允许比较 TFP 优势的空间和时间变化。三个模拟的水文通量和一个状态变量用作敏感性分析的目标变量：径流、实际蒸散量、土壤水分 （SM） 和地下水补给。该分析导致了空间参数优势的一致且合理的模式。蒸散参数主导实际蒸散和 SM。径流和补给主要由土壤质地、地下和渗流参数控制。空间与时间变异性的相关性因模型参数和目标变量而异。在某些情况下，参数敏感性与相应过程的量级有关。MPR 解释了主要参数的低空间和时间变异性。 鉴于这些结果，建议进行联合时空分析，以更好地了解模型参数如何驱动水文模型中的模拟状态和通量，从而提高过程准确性。