The effect of model calibration on the projection of climate change impact on hydrological indicators was assessed by employing variants of a pan-European hydrological model driven by forcing data from an ensemble of climate models. The hydrological model was calibrated using three approaches: calibration at the outlets of major river basins, regionalization through calibration of smaller scale catchments with unique catchment characteristics, and building a model ensemble by sampling model parameters from the regionalized model. The large-scale patterns of the change signals projected by all model variants were found to be similar for the different indicators. Catchment scale differences were observed between the projections of the model calibrated for the major river basins and the other two model variants. The distributions of the median change signals projected by the ensemble model were found to be similar to the distributions of the change signals projected by the regionalized model for all hydrological indicators. The study highlights that the spatial detail to which model calibration is performed can highly influence the catchment scale detail in the projection of climate change impact on hydrological indicators, with an absolute difference in the projections of the locally calibrated model and the model calibrated for the major river basins ranging between 0 and 55% for mean annual discharge, while it has little effect on the large-scale pattern of the projection.

中文翻译：

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模式校准策略对大陆尺度水文指标气候预测的影响

模型校准对气候变化对水文指标影响的预测的影响是通过采用由气候模型集合的强制数据驱动的泛欧洲水文模型的变体来评估的。水文模型使用三种方法校准：在主要流域的出口处校准，通过校准具有独特流域特征的较小规模流域进行区域化，以及通过从区域化模型中采样模型参数来构建模型集合。发现所有模型变体预测的变化信号的大规模模式对于不同的指标是相似的。在为主要流域校准的模型预测与其他两个模型变体之间观察到流域规模差异。发现集合模型预测的中值变化信号的分布与区域化模型预测的所有水文指标的变化信号分布相似。研究强调，在气候变化对水文指标影响的预测中，模型校准所针对的空间细节可以极大地影响流域尺度细节，局部校准模型的预测与主要校准模型的预测存在绝对差异。流域的年平均流量在 0% 到 55% 之间，而对预测的大尺度格局影响不大。