The Arctic’s winter water cycle is rapidly changing, with implications for snow moisture sources and transport processes. Stable isotope values (δ¹⁸O, δ²H, d-excess) of the Arctic snowpack have potential to provide proxy records of these processes, yet it is unclear how well the isotope values of individual snowfall events are preserved within snow profiles. Here, we present water isotope data from multiple taiga and tundra snow profiles sampled in Arctic Alaska and Finland, respectively, during winter 2018–2019. We compare the snowpack isotope stratigraphy with meteoric water isotopes (vapor and precipitation) during snowfall days, and combine our measurements with satellite observations and reanalysis data. Our analyses indicate that synoptic-scale atmospheric circulation and regional sea ice coverage are key drivers of the source, amount, and isotopic composition of Arctic snowpacks. We find that the western Arctic tundra snowpack profiles in Alaska preserved the isotope values for the most recent storm; however, post depositional processes modified the remaining isotope profiles. The overall seasonal evolution in the vapor isotope values were better preserved in taiga snow isotope profiles in the eastern Arctic, where there is significantly less wind-driven redistribution than in the open Alaskan tundra. We demonstrate the potential of the seasonal snowpack to provide a useful proxy for Arctic winter-time moisture sources and propose future analyses.

中文翻译：

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北极雪同位素水文学：雪水蒸气对比研究

北极的冬季水循环正在迅速变化，这对雪中的水分来源和运输过程产生了影响。稳定同位素值（δ ¹⁸ O，δ ² H，d-过量北极积雪的潜力有可能提供这些过程的代理记录，但尚不清楚单个降雪事件的同位素值在积雪剖面中的保留程度如何。在这里，我们提供了2018-2019年冬季分别来自北极阿拉斯加和芬兰的多个针叶林和冻原雪剖面的水同位素数据。我们将降雪期间的积雪同位素地层学与流水同位素（蒸汽和降水）进行了比较，并将我们的测量结果与卫星观测和再分析数据相结合。我们的分析表明，天气尺度的大气环流和区域性海冰覆盖是北极积雪的来源，数量和同位素组成的关键驱动因素。我们发现阿拉斯加的北极北极苔原积雪剖面保留了最近风暴的同位素值。但是，沉积后的过程改变了其余的同位素分布。在北极东部的针叶林雪同位素剖面中，蒸气同位素值的总体季节性变化得到了更好的保留，与阿拉斯加寒带苔原相比，那里的风能再分配明显更少。我们证明了季节性积雪为北极冬季冬季水分来源提供有用代理的潜力，并提出了今后的分析建议。