Transformations of runoff chemistry in the Arctic tundra, Northwest Territories, Canada
Transformations of runoff chemistry in the Arctic tundra, Northwest Territories, Canada
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加拿大西北地区北极苔原径流化学的转变
DOI：
10.1002/hyp.6083
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发表时间：
2006
影响因子：
3.2
通讯作者：
J. Pomeroy
中科院分区：
文献类型：
--
作者：
W. Quinton;J. Pomeroy
研究了北极冻原流域融雪水化学成分在融化、淋洗和径流过程中的变化。从融雪表面到95·5公顷流域出口沿沿着路径流动的水的化学性质与相关水文过程有关。在这样做的过程中，本文提供了物理基础上的解释与融雪和降雨沿沿着水文路径到流出口的径流水的主要离子浓度和负荷的转换。晚卧雪堆被发现影响离子化学在相邻河段的河道很大。随着富含离子的融水的初始脉冲从雪堆中排出并通过山坡流道输送，大多数离子的浓度增加，峰值离子脉冲的持续时间延长。在坡面流的前3 m，除NO${3}^{-}$外，其它离子的浓度都增加了1 ~ 2个数量级，其中K+、Ca 2+和Mg 2+的增加幅度最大。这大致相当于相对稀释的水通过0.25 m的非饱和土壤渗透而导致的浓度增加。Na+和Cl−是融雪水中的主要离子，而Ca 2+和Mg 2+则是坡面径流中的主要离子。在一个大的融化雪堆下面的斜坡上，在土壤的饱和层中流动的融水的离子浓度非常相似，在地表径流中发现的相对较稀的浓度。然而，一旦雪堆消融，地下流的离子浓度增加超过母体融水浓度。三个季节性特征的水化学制度被确定在一个流到达邻近晚卧雪堆。在前两个阶段，河道中的水化学非常类似于山坡排水。在第三阶段，河流中的地球化学过程，包括风化/Ca 2+和Mg 2+的离子交换，是河流水化学的主要控制因素。版权所有© 2006约翰威利父子有限公司。
The transformation of snowmelt water chemical composition during melt, elution and runoff in an Arctic tundra basin is investigated. The chemistry of the water flowing along pathways from the surface of melting snow to the 95·5 ha basin outlet is related to relevant hydrological processes. In so doing, this paper offers physically based explanations for the transformation of major ion concentrations and loads of runoff water associated with snowmelt and rainfall along hydrological pathways to the stream outlet. Late‐lying snowdrifts were found to influence the ion chemistry in adjacent reaches of the stream channel greatly. As the initial pulse of ion‐rich melt water drained from the snowdrift and was conveyed through hillslope flowpaths, the concentrations of most ions increased, and the duration of the peak ionic pulse lengthened. Over the first 3 m of overland flow, the concentrations of all ions except for NO$_{3}^{-}$ increased by one to two orders of magnitude, with the largest increase for K+, Ca2+ and Mg2+. This was roughly equivalent to the concentration increase that resulted from percolation of relatively dilute water through 0·25 m of unsaturated soil. The Na+ and Cl− were the dominant ions in snowmelt water, whereas Ca2+ and Mg2+ dominated the hillslope runoff. On slopes below a large melting snowdrift, ion concentrations of melt water flowing in the saturated layer of the soil were very similar to the relatively dilute concentrations found in surface runoff. However, once the snowdrift ablated, ion concentrations of subsurface flow increased above parent melt‐water concentrations. Three seasonally characteristic hydrochemical regimes were identified in a stream reach adjacent to late‐lying snowdrifts. In the first two stages, the water chemistry in the stream channel strongly resembled the hillslope drainage water. In the third stage, in‐stream geochemical processes, including the weathering/ion exchange of Ca2+ and Mg2+, were the main control of streamwater chemistry. Copyright © 2006 John Wiley & Sons, Ltd.