Inferring groundwater contributions and pathways to streamflow during snowmelt over multiple years in a discontinuous permafrost subarctic environment (Yukon, Canada)
Inferring groundwater contributions and pathways to streamflow during snowmelt over multiple years in a discontinuous permafrost subarctic environment (Yukon, Canada)
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DOI：
10.1007/s10040-012-0920-9
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发表时间：
2013-02-01
影响因子：
2.8
通讯作者：
Duarte, Celina M.
中科院分区：
文献类型：
--
作者：
Carey, Sean K.;Boucher, Jessica L.;Duarte, Celina M.
对北方大型河流的研究表明，随着永久冻土的融化，更深层的地下水流动路径变得活跃，导致基流增加，风化离子浓度增加，溪流中溶解有机碳浓度降低。相比之下，在对地下水/地表水相互作用的理解发展的源头-集水区尺度上，气候和水文的年际变化导致复杂的水文和化学变化响应。本文利用稳定同位素、主要溶解离子和水文测量数据，对加拿大育空地区高山不连续多年冻土环境进行了为期4年的径流调查，以加深对径流生成过程年际变率的认识。稳定同位素结果表明，融雪过程中，集水区储存的水在融雪过程中占主导地位，而溶解离子结果表明，在融雪过程中，地下水通道主要发生在近地表。溶解的有机碳年际变化，反映了熔融模式的变化，而深层流动路径产生的风化离子被稀释。总雪水当量对融雪水到达河流的比例或径流比没有主要影响。多年的结果强调了在短时间尺度上的相当大的变化，限制了我们在水源尺度上探测气候变化对地下水影响的能力。
Research on large northern rivers suggests that as permafrost thaws, deeper groundwater flowpaths become active, resulting in greater baseflow, increased concentrations of weathering ions and reduced concentrations of dissolved organic carbon in the streamflow. In contrast, at the headwater-catchment scale, where understanding of groundwater/surface-water interactions is developed, inter-annual variability in climate and hydrology result in complex hydrological and chemical responses to change. This paper reports on a 4-year runoff investigation in an alpine discontinuous permafrost environment in Yukon, Canada, using stable isotopes, major dissolved ions and hydrometric data, to provide enhanced insight into the inter-annual-variability runoff-generation processes. Stable isotope results suggest that pre-event (old) water stored within the catchment dominates the snowmelt hydrograph, and dissolved ion results reveal that groundwater pathways occur predominantly in the near-surface during freshet. Dissolved organic carbon varies inter-annually, reflecting changing melt patterns, whereas weathering ions generated from deeper flowpaths become diluted. The total snow-water equivalent does not have a major influence on the fraction of snowmelt water reaching the stream or the runoff ratio. Results from multiple years highlight the considerable variability over short time scales, limiting our ability to detect climate-change influences on groundwater at the headwater scale.