The delivery of dissolved organic carbon from a forested hillslope to a headwater stream in southeastern Pennsylvania, USA
The delivery of dissolved organic carbon from a forested hillslope to a headwater stream in southeastern Pennsylvania, USA
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DOI：
10.1002/2014wr015635
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发表时间：
2014-07
影响因子：
5.4
通讯作者：
Y. Mei;G. Hornberger;L. Kaplan;J. Newbold;A. Aufdenkampe
中科院分区：
文献类型：
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作者：
Y. Mei;G. Hornberger;L. Kaplan;J. Newbold;A. Aufdenkampe
河岸带土壤富含有机碳，是向邻近河流输送溶解有机碳(DOC)的来源，但控制DOC输送的水文因素尚未得到很好的描述。建立了宾夕法尼亚山前流域东南部山坡样带风暴过程中可生物降解DOC(BDOC)和难降解DOC(RDoC)的二维变饱和流动和反应输运有限元模型。模型表明，坡面出水中的DOC浓度在流量过程线的下降处达到峰值，这一时间序列符合冲刷假说。采用蒙特卡罗模拟与多元线性回归相结合的方法，分析了影响河流洪峰流量与DOC峰值浓度之间滞后时间的因素。这一结果与以前的研究一致，表明风暴期间输送到溪流中的大部分DOC来自河岸带。此外，模型还表明，洪水波持续时间和河岸土壤的水力性质对控制坡面出水中DOC峰值流量与峰值浓度之间的滞后时间具有重要作用。
Riparian soils, rich in organic carbon, act as a source of dissolved organic carbon (DOC) to the adjacent stream, but the hydrologic factors that control the delivery of DOC are not well characterized. A mechanistic two‐dimensional, variably saturated flow and reactive transport finite element model (FEM) was developed to explore both biodegradable DOC (BDOC) and refractory DOC (RDOC) delivery processes during storms for a hillslope transect in a southeastern Pennsylvania Piedmont watershed. The model indicated that DOC concentrations in outflow from a hillslope peaked on the falling limb of the discharge hydrograph, a temporal sequence consistent with a flushing hypothesis. Factors that control the lag time between the stream water peak discharge and peak DOC concentration were analyzed using a Monte Carlo simulation coupled with a multiple linear regression. The results are consistent with previous studies showing that the majority of DOC delivered to a stream during storms originates from the riparian zone. Further, the model suggests that the duration of the flood wave and hydraulic properties of the riparian soil play important roles in controlling the lag time between peak discharge and peak DOC concentration in outflow from a hillslope.