Cold region hydrology is conditioned by distinct cryospheric and hydrological processes. While snowmelt is the main contributor to both surface and subsurface flows, seasonally frozen soil also influences the partition of meltwater and rain between these flows. Cold regions of the Northern Hemisphere midlatitudes have been shown to be sensitive to climate change. Assessing the impacts of climate change on the hydrology of this region is therefore crucial, as it supports a significant amount of population relying on hydrological services and subjected to changing hydrological risks. We present an exhaustive review of the literature on historical and projected future changes on cold region hydrology in response to climate change. Changes in snow, soil, and streamflow key metrics were investigated and summarized at the hemispheric scale, down to the basin scale. We found substantial evidence of both historical and projected changes in the reviewed hydrological metrics. These metrics were shown to display different sensitivities to climate change, depending on the cold season temperature regime of a given region. Given the historical and projected future warming during the 21st century, the most drastic changes were found to be occurring over regions with near-freezing air temperatures. Colder regions, on the other hand, were found to be comparatively less sensitive to climate change. The complex interactions between the snow and soil metrics resulted in either colder or warmer soils, which led to increasing or decreasing frost depths, influencing the partitioning rates between the surface and subsurface flows. The most consistent and salient hydrological responses to both historical and projected climate change were an earlier occurrence of snowmelt floods, an overall increase in water availability and streamflow during winter, and a decrease in water availability and streamflow during the warm season, which calls for renewed assessments of existing water supply and flood risk management strategies.

中文翻译：

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气候变化对北部中纬度寒区水文的影响

寒冷地区的水文受到不同的冰冻圈和水文过程的制约。虽然融雪是地表和地下流的主要贡献者，但季节性冻土也会影响融水和雨水在这些流之间的分配。北半球中纬度寒冷地区已被证明对气候变化很敏感。因此，评估气候变化对该地区水文的影响至关重要，因为它支持着大量依赖水文服务并遭受不断变化的水文风险的人口。我们对有关寒冷地区水文响应气候变化的历史和预计未来变化的文献进行了详尽的回顾。在半球尺度上调查和总结了雪、土壤和流量关键指标的变化，下降到盆地规模。我们在审查的水文指标中发现了历史变化和预测变化的大量证据。这些指标显示出对气候变化的不同敏感性，具体取决于给定地区的寒冷季节温度状况。考虑到 21 世纪历史和预计的未来变暖，发现最剧烈的变化发生在气温接近冰点的地区。另一方面，较冷的地区对气候变化的敏感度相对较低。雪和土壤指标之间复杂的相互作用导致土壤变冷或变暖，从而导致霜深度增加或减少，影响地表和地下流之间的分配率。