Winter runoff events pose an unquantified continental-scale risk of high wintertime nutrient export
Winter runoff events pose an unquantified continental-scale risk of high wintertime nutrient export
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DOI：
10.1088/1748-9326/ac8be5
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发表时间：
2022
影响因子：
6.7
通讯作者：
E. Seybold;R. Dwivedi;K. Musselman;D. Kincaid;A. Schroth;A. Classen;J. Perdrial;E. Adair
中科院分区：
文献类型：
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作者：
E. Seybold;R. Dwivedi;K. Musselman;D. Kincaid;A. Schroth;A. Classen;J. Perdrial;E. Adair
冰雪覆盖地区的冬季已经变暖，可能会改变营养物质输出的时间和幅度，导致水质发生无法量化的变化。间歇性、季节性和永久性的积雪覆盖了全球一半以上的陆地表面。变暖减少了限制冬季径流和营养物质运输的寒冷条件，而寒冷季节的融雪、冬季降雨量和雪中降雨量都有所增加。我们使用现有的地理空间数据集（覆盖在氮和磷库存上的雨雪频率）来确定美国（US）邻近地区的水质可能受到这种变化的威胁。接下来，为了说明这些事件的潜在出口影响，我们检查了来自美国最大的河流流域密西西比河流域的大型区域性雨雪事件的流量和浊度数据。我们发现，雨雪是地球仪大面积地区的主要洪水生成机制（Berghuijs等人，2019年水资源。Res. 55 4582-93; Berghuijs等人2016 Geophys.保留信函43 4382-90），影响了美国53%的毗连区，并使美国50%的氮和磷库（美国毗连区的43%）面临向地下水和地表水输出的风险。此外，2019年密西西比河流域的雨雪事件表明，这些事件可能对冬季养分输送产生巨大的级联影响。我们认为，在历史上积雪覆盖的地区，冬季排放量低，营养输送的假设不再成立。然而，至关重要的是，我们缺乏足够的数据来准确地测量和预测这些情节和潜在的大型冬季营养输出事件在区域到大陆的规模。
Winters in snow-covered regions have warmed, likely shifting the timing and magnitude of nutrient export, leading to unquantified changes in water quality. Intermittent, seasonal, and permanent snow covers more than half of the global land surface. Warming has reduced the cold conditions that limit winter runoff and nutrient transport, while cold season snowmelt, the amount of winter precipitation falling as rain, and rain-on-snow have increased. We used existing geospatial datasets (rain-on-snow frequency overlain on nitrogen and phosphorous inventories) to identify areas of the contiguous United States (US) where water quality could be threatened by this change. Next, to illustrate the potential export impacts of these events, we examined flow and turbidity data from a large regional rain-on-snow event in the United States’ largest river basin, the Mississippi River Basin. We show that rain-on-snow, a major flood-generating mechanism for large areas of the globe (Berghuijs et al 2019 Water Resour. Res. 55 4582–93; Berghuijs et al 2016 Geophys. Res. Lett. 43 4382–90), affects 53% of the contiguous US and puts 50% of US nitrogen and phosphorus pools (43% of the contiguous US) at risk of export to groundwater and surface water. Further, the 2019 rain-on-snow event in the Mississippi River Basin demonstrates that these events could have large, cascading impacts on winter nutrient transport. We suggest that the assumption of low wintertime discharge and nutrient transport in historically snow-covered regions no longer holds. Critically, however, we lack sufficient data to accurately measure and predict these episodic and potentially large wintertime nutrient export events at regional to continental scales.