Seasonal hyporheic temperature dynamics over riffle bedforms
Seasonal hyporheic temperature dynamics over riffle bedforms
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DOI：
10.1002/hyp.7256
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发表时间：
2009-07-15
影响因子：
3.2
通讯作者：
Bradley, Chris
中科院分区：
文献类型：
--
作者：
Hannah, David M.;Malcolm, Iain A.;Bradley, Chris
由于潜水带的生态和生物地球化学意义，以及它对调节河流温度的潜力，人们对河床温度越来越感兴趣。冲沟表现出复杂的热行为，推测是由地下水-地表水(GW-SW)相互作用的局部变化引起的，但到目前为止，大多数研究都是在高地/砾石床/硬岩集水区进行的。因此，本文的目的是：(1)描述砂岩下低地河流流域(英国什罗普郡特恩)两条河流(R1和R2)上潜流温度的时空变异性；(2)通过推断潜流过程和GW-SW相互作用的影响来解释热动力学。海绵状(头部、冠部和尾部为0.1.0.2和0.4m)、水柱、泉水和气温在22个月的时间里以15分钟的分辨率采集，并用于探索季节变化。钻孔水位和温度可以洞察地下水在一年中的变异性。夏季(冬季)潜水温度比水柱冷(暖)，春秋两季交汇。扰流头和R2波峰产生较小的温度梯度。与RI尾部垂直差较大。RI波峰温度相似且衰减(参见水柱)在所有深度。R2尾部温度与地表水有显著差异。因此，潜水温度在河流之间和河流之间随时间变化，反映了：(1)水文气候对河流和地下水温度的控制，以及(2)水文、局部地貌和沉积对地表水和地下水通量的控制。这项研究表明，与深度相关的河床温度时间序列在理解潜流带过程和GW-西南相互作用方面是有用的。版权所有(C)2009 John Wiley&Sons，Ltd.
There is growing interest in riverbed temperature due to the ecological and biogeochemical significance of the hyporheic zone, and its potential to moderate river temperature. Riffles exhibit complex thermal behaviour, hypothesized to be caused by local alteration of groundwater-surface water (GW-SW) interactions, but hitherto most research has been in upland/gravel-bed/hard rock catchments. Accordingly, this article aims: (1) to characterize spatio-temporal variability in hyporheic temperature over two riffles (R1 and R2) in a lowland river basin (Tern, Shropshire, UK) underlain by sandstone, and (2) to explain thermal dynamics by inferring hyporheic processes and the influence of GW-SW interactions. Hyporheic (riffle head, crest and tail at 0.1. 0.2 and 0.4 m), water column, spring water and air temperature were collected at 15 min resolution over 22 months and used to explore seasonal variations. Borehole water levels and temperature provide insight into groundwater variability over a hydrological year. Hyporheic temperature is cooler (warmer) than water column in summer (winter), with convergence in spring and autumn. Riffle heads and R2 crest yield small thermal gradients. and RI tail larger vertical difference. RI crest temperature is similar and attenuated (cf. water column) at all depths. R2 tail temperature differs markedly from surface water. Thus, hyporheic temperature varies temporally across and between riffles, reflecting: (1) hydroclimatological controls on river and groundwater temperature, and (2) hydrological, local morphological and sedimentary controls on surface water and groundwater flux. This research demonstrates the utility of depth-related riverbed temperature time-series in understanding hyporheic zone processes and GW-SW interactions. Copyright (C) 2009 John Wiley & Sons, Ltd.