The Arctic has been warming faster than the global average during recent decades, and trends are projected to continue through the twenty-first century. Analysis of climate change impacts across the Arctic using dynamical models has almost exclusively been limited to outputs from global climate models or coarser regional climate models. Coarse resolution simulations limit the representation of physical processes, particularly in areas of complex topography and high land-surface heterogeneity. Here, current climate reference and future regional climate model simulations based on the RCP8.5 scenario over Alaska at 4 km grid spacing are compared to identify changes in snowfall and snowpack. In general, results show increases in total precipitation, large decreases in snowfall fractional contribution over 30% in some areas, decreases in snowpack season length by 50–100 days in lower elevations and along the southern Alaskan coastline, and decreases in snow water equivalent. However, increases in snowfall and snowpack of sometimes greater than 20% are evident for some colder northern areas and at the highest elevations in southern Alaska. The most significant changes in snow cover and snowfall fractional contributions occur during the spring and fall seasons. Finally, the spatial pattern of winter temperatures above freezing has small-scale spatial features tied to the topography. Such areas would not be resolved with coarser resolution regional or global climate model simulations.

中文翻译：

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高分辨率区域气候模拟描绘的阿拉斯加水文气候变化

近几十年来，北极的变暖速度超过全球平均水平，预计这一趋势将持续到 21 世纪。使用动力学模型对整个北极的气候变化影响进行分析几乎完全仅限于全球气候模型或较粗略的区域气候模型的输出。粗分辨率模拟限制了物理过程的表示，特别是在复杂地形和高度地表异质性的区域。在这里，基于阿拉斯加上空 4 公里网格间距的 RCP8.5 情景的当前气候参考和未来区域气候模型模拟进行比较，以确定降雪和积雪的变化。总体而言，结果显示总降水量增加，部分地区降雪比例贡献大幅下降30%以上，在低海拔地区和阿拉斯加南部海岸线，积雪季节长度减少 50-100 天，雪水当量减少。然而，在一些较冷的北部地区和阿拉斯加南部海拔最高的地区，降雪和积雪的增加有时会超过 20%。积雪和降雪部分贡献的最显着变化发生在春季和秋季。最后，冬季气温在零度以上的空间格局具有与地形相关的小尺度空间特征。这些区域将无法通过较粗分辨率的区域或全球气候模型模拟来解决。在一些较冷的北部地区和阿拉斯加南部的最高海拔地区，降雪和积雪的增加有时会超过 20%。积雪和降雪部分贡献的最显着变化发生在春季和秋季。最后，冬季气温在零度以上的空间格局具有与地形相关的小尺度空间特征。这些区域将无法通过较粗分辨率的区域或全球气候模型模拟来解决。在一些较冷的北部地区和阿拉斯加南部的最高海拔地区，降雪和积雪的增加有时会超过 20%。积雪和降雪部分贡献的最显着变化发生在春季和秋季。最后，冬季气温在零度以上的空间格局具有与地形相关的小尺度空间特征。这些区域将无法通过较粗分辨率的区域或全球气候模型模拟来解决。