Abstract. Climate change is one of the greatest threats currently facing the world's environment. In Norway, a change in climate will strongly affect the pattern, frequency, and magnitudes of stream flows. However, it is challenging to quantify to what extent the change will affect the flow patterns and floods from small rural catchments due to the unavailability or inadequacy of hydro-meteorological data for the calibration of hydrological models and due to the tailoring of methods to a small-scale level. To provide meaningful climate impact studies at the level of small catchments, it is therefore beneficial to use high-spatial- and high-temporal-resolution climate projections as input to a high-resolution hydrological model. In this study, we used such a model chain to assess the impacts of climate change on the flow patterns and frequency of floods in small ungauged rural catchments in western Norway. We used a new high-resolution regional climate projection, with improved performance regarding the precipitation distribution, and a regionalized hydrological model (distance distribution dynamics) between a reference period (1981–2011) and a future period (2070–2100). The flow-duration curves for all study catchments show more wet periods in the future than during the reference period. The results also show that in the future period, the mean annual flow increases by 16 % to 33 %. The mean annual maximum floods increase by 29 % to 38 %, and floods of 2- to 200-year return periods increase by 16 % to 43 %. The results are based on the RCP8.5 scenario from a single climate model simulation tailored to the Bergen region in western Norway, and the results should be interpreted in this context. The results should therefore be seen in consideration of other scenarios for the region to address the uncertainty. Nevertheless, the study increases our knowledge and understanding of the hydrological impacts of climate change on small catchments in the Bergen area in the western part of Norway.

中文翻译：

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气候变化对未经测量的小型集水区的水文影响——来自全球气候模型-区域气候模型-水文模型链的结果

摘要。气候变化是目前世界环境面临的最大威胁之一。在挪威，气候变化将强烈影响河流流量的模式、频率和大小。然而，由于用于校准水文模型的水文气象数据不可用或不充分，以及由于对小型农村集水区的方法进行了调整，量化变化将在多大程度上影响小型农村集水区的流量模式和洪水具有挑战性。 -规模水平。为了在小流域水平提供有意义的气候影响研究，因此使用高空间和高时间分辨率气候预测作为高分辨率水文模型的输入是有益的。在这项研究中，我们使用这样一个模型链来评估气候变化对挪威西部小型未测量农村集水区的流量模式和洪水频率的影响。我们使用了新的高分辨率区域气候预测，改进了降水分布的性能，以及参考期（1981-2011 年）和未来时期（2070-2100 年）之间的区域化水文模型（距离分布动态）。所有研究流域的流量-持续时间曲线显示，未来的湿润期比参考期多。结果还表明，未来一段时间内，年均流量将增加16%～33%。年平均最大洪水增加 29% 至 38%，2 至 200 年重现期的洪水增加 16% 至 43%。结果基于 RCP8。5 情景来自为挪威西部卑尔根地区量身定制的单一气候模型模拟，结果应在此背景下进行解释。因此，应在考虑该地区解决不确定性的其他情景时看到结果。尽管如此，这项研究增加了我们对气候变化对挪威西部卑尔根地区小集水区水文影响的认识和理解。