Characterizing the role of hydrological processes on lake water balances in the Old Crow Flats, Yukon Territory, Canada, using water isotope tracers.
Characterizing the role of hydrological processes on lake water balances in the Old Crow Flats, Yukon Territory, Canada, using water isotope tracers.
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DOI：
10.1016/j.jhydrol.2010.03.012
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发表时间：
2010-05
影响因子：
6.4
通讯作者：
K. Turner;B. Wolfe;T. Edwards
中科院分区：
文献类型：
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作者：
K. Turner;B. Wolfe;T. Edwards
我们采用水同位素示踪剂，以评估水文过程控制湖泊水平衡的老乌鸦单位（OCF）景观，北方育空地区，加拿大。2007年6月和7月对五十六个湖泊进行了采样，2007年9月对其中26个湖泊进行了重新采样。根据δ 18 O-δ 2 H同位素空间演化模式、入湖水组成（δI）和蒸发入湖（E/I）计算以及野外观测资料，划分出了融雪型湖泊、湖泊型湖泊、地下水型湖泊、蒸发型湖泊和排泄型湖泊，它们代表了影响湖泊水量平衡的主要水文过程。这些结果突出了湖泊水平衡条件的多样性，在OCF，这是密切相关的景观特征。以融雪为主的湖泊位于植被覆盖较密的地方，这些地方的积雪被盛行的东北风所夹带。以降雨为主的湖泊占据了苔原植被稀疏的地区，那里积雪较少。受地下水影响的牛轭湖位于沿着高阶河流和小溪渠道的洪泛区，并在整个无冰季节从融雪补给的渠道沼泽和次表层流中获得输入。在2007年开放水域季节，只有一个盆地成为蒸发占主导地位，可能是因为极高的降水在前夏末，冬末和早春抵消蒸汽损失。然而，以融雪为主的湖泊似乎比以融雪为主和地下水影响的湖泊更容易受到蒸发下降的影响，许多湖泊可能会在干燥的夏季演变为以蒸发为主。在整个景观中经常观察到排水湖，在大多数情况下，可能是由于水位升高和水体之间的河道侵蚀造成的。2007年6月初，异常高的融雪和/或降雨量引发了两个湖泊的排水，溢流导致了出口渠道的快速侵蚀。我们的湖泊类型和相应的同位素演化模式的分类可能是典型的其他热岩溶景观和他们的识别可以用来更好地预测水文响应正在进行的气候变化。
We employ water isotope tracers to assess hydrological processes controlling lake water balances in the Old Crow Flats (OCF) landscape, northern Yukon Territory, Canada. Fifty-six lakes were sampled in June and July 2007 and 26 of these were re-sampled in September 2007. Based on patterns of isotopic evolution in δ18O–δ2H space, calculations of input water compositions (δI) and evaporation-to-inflow (E/I) ratios, and field observations we identify snowmelt-dominated, rainfall-dominated, groundwater-influenced, evaporation-dominated and drained lake types, which represent the dominant hydrological process influencing the lake water balance. These results highlight the diversity in lake water balance conditions in the OCF, which are strongly associated with landscape characteristics. Snowmelt-dominated lakes are located where more dense vegetation cover entraps snow transported by prevailing northeasterly winds. Rainfall-dominated lakes occupy areas of sparse tundra vegetation cover where less snow accumulates. Groundwater-influenced oxbow lakes are located along the floodplain of higher-order river and creek channels and receive input throughout the ice-free season from snowmelt-recharged channel fens and sub-surface flow. Only one basin became evaporation-dominated during the 2007 open-water season probably because extremely high precipitation during the preceding late summer, late winter and early spring offset vapour loss. However, rainfall-dominated lakes appear to be more susceptible to evaporative drawdown than snowmelt-dominated and groundwater-influenced lakes, and many would likely evolve to evaporation-dominated during drier summers. Drained lakes are commonly observed throughout the landscape and in most cases likely result from elevated water levels and channel erosion between waterbodies. Unusually high amounts of snowmelt and/or rainfall triggered the drainage of two lakes in early June 2007 in which overflow led to rapid erosion of outlet channels. Our classification of lake types and corresponding isotopic evolution patterns are likely typical of other thermokarst landscapes and their identification could be used to better predict hydrological responses to ongoing climate change.