Abstract This study assesses snow response in the Assiniboine-Red River basin, located in the Lake Winnipeg watershed, due to anthropogenic climate change. We use a process-based distributed snow model driven by an ensemble of eight statistically downscaled global climate models (GCMs) to project future changes under policy-relevant global mean temperature (GMT) increases of 1.0 °C to 3.0 °C above the pre-industrial period. Results indicate that basin scale seasonal warmings generally exceed the GMT increases, with greater warming in winter months. The majority of GCMs project wetter winters and springs, and drier summers, while autumn could become either drier or wetter. An analysis of snow water equivalent (SWE) responses under GMT changes reveal higher correlations of snow cover duration (SCD), snowmelt rate, maximum SWE (SWEmax) and timing of SWEmax with winter and spring temperatures compared to precipitation, implying that these variables are predominantly temperature controlled. Consequently, under the GMT increases from 1.0 °C to 3.0 °C, the basin will experience successively shorter SCD, slower snowmelt, smaller monthly SWE and SWEmax, earlier SWEmax, and a transition from snow-dominated to rain-snow hybrid regime. Further, while the winter precipitation increases for some GCMs compensate the temperature-driven changes in SWE, the increases for most GCMs occur as rainfall, thus limiting the positive contribution to snow storage. Overall, this study provides a detailed diagnosis of the snow regime changes under the policy-relevant GMT changes, and a basis for further investigations on water quantity and quality changes.

中文翻译：

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Assiniboine-Red River 流域的积雪响应与预计的全球变暖 1.0 °C 至 3.0 °C 相关

摘要 本研究评估了位于温尼伯湖流域的 Assiniboine-Red 河流域因人为气候变化引起的降雪响应。我们使用由八个统计缩减全球气候模型 (GCM) 的集合驱动的基于过程的分布式雪模型来预测与政策相关的全球平均温度 (GMT) 比之前高出 1.0°C 至 3.0°C 下的未来变化。工业时期。结果表明，流域尺度的季节性变暖通常超过 GMT 的增加，冬季月份的变暖幅度更大。大多数 GCM 预测冬季和春季更潮湿，夏季更干燥，而秋季可能变得更干燥或更潮湿。对 GMT 变化下雪水当量 (SWE) 响应的分析显示，积雪持续时间 (SCD)、融雪率、与降水相比，最大 SWE (SWEmax) 和 SWEmax 的时间与冬季和春季温度相比，这意味着这些变量主要受温度控制。因此，在格林威治标准时间从 1.0 °C 增加到 3.0 °C 的情况下，流域将依次经历更短的 SCD、更慢的融雪、更小的月 SWE 和 SWEmax、更早的 SWEmax，以及从以雪为主的过渡到雨雪混合制度。此外，虽然某些 GCM 的冬季降水增加补偿了 SWE 中温度驱动的变化，但大多数 GCM 的增加以降雨形式发生，从而限制了对积雪的积极贡献。总体而言，本研究提供了政策相关 GMT 变化下雪情变化的详细诊断，并为进一步调查水量和水质变化提供了基础。