We performed a twofold intercomparison of river discharge regulated by dams under multiple meteorological forcings among multiple global hydrological models for a historical period by simulation. Paper II provides an intercomparison of river discharge simulated by five hydrological models under four meteorological forcings. This is the first global multimodel intercomparison study on dam-regulated river flow. Although the simulations were conducted globally, the Missouri-Mississippi and Green- Colorado Rivers were chosen as case-study sites in this study. The hydrological models incorporate generic schemes of dam operation, not specific to a certain dam. We examined river discharge on a longitudinal section of river channels to investigate the effects of dams on simulated discharge, especially at the seasonal time scale. We found that the magnitude of dam regulation differed considerably among the hydrological models. The difference was attributable not only to dam operation schemes but also to the magnitude of simulated river discharge flowing into dams. That is, although a similar algorithm of dam operation schemes was incorporated in different hydrological models, the magnitude of dam regulation substantially differed among the models. Intermodel discrepancies tended to decrease toward the lower reaches of these river basins, which means model dependence is less significant toward lower reaches. These case-study results imply that, intermodel comparisons of river discharge should be made at different locations along the river's course to critically examine the performance of hydrological models because the performance can vary with the locations.

中文翻译：

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以大坝运行为重点的全球河流流量模拟的比对——在两个案例研究流域（密苏里-密西西比和格林-科罗拉多）的多模型分析

我们通过模拟对历史时期多个全球水文模型在多种气象强迫下由大坝调节的河流流量进行了双重比对。论文二提供了在四种气象强迫下由五种水文模型模拟的河流流量的比对。这是第一个关于大坝调节河流流量的全球多模式比对研究。尽管模拟是在全球范围内进行的，但本研究选择了密苏里-密西西比河和格林-科罗拉多河作为案例研究地点。水文模型包含大坝运行的通用方案，而不是特定于某个大坝。我们检查了河道纵剖面上的河流流量，以研究大坝对模拟流量的影响，尤其是在季节性时间尺度上。我们发现大坝调节的幅度在不同的水文模型之间存在很大差异。这种差异不仅归因于大坝运营方案，还归因于流入大坝的模拟河流流量的大小。也就是说，虽然在不同的水文模型中采用了类似的大坝运行方案算法，但不同模型之间的大坝调节幅度存在很大差异。模型间差异趋向于向这些流域的下游减少，这意味着模型对下游的依赖性不那么显着。这些案例研究结果意味着，应该在沿河道的不同位置对河流流量进行模型间比较，以批判性地检查水文模型的性能，因为性能可能因位置而异。