气候变化领域集成服务门户(CCPortal): Spatio-temporal relevance and controls of preferential flow at the landscape scale

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DOI	10.5194/hess-23-4869-2019
	Spatio-temporal relevance and controls of preferential flow at the landscape scale
	Demand D.; Blume T.; Weiler M.
发表日期	2019
ISSN	1027-5606
起始页码	4869
结束页码	4889
卷号	23 期号:11
英文摘要	The spatial and temporal controls of preferential flow (PF) during infiltration are still not fully understood. As soil moisture sensor networks allow us to capture infiltration responses in high temporal and spatial resolution, our study is based on a large-scale sensor network with 135 soil moisture profiles distributed across a complex catchment. The experimental design covers three major geological regions (slate, marl, sandstone) and two land covers (forest, grassland) in Luxembourg. We analyzed the responses of up to 353 rainfall events for each of the 135 soil moisture profiles. Non-sequential responses (NSRs) within the soil moisture depth profiles were taken as one indication of bypass flow. For sequential responses maximum porewater velocities (vmax) were determined from the observations and compared with velocity estimates of capillary flow. A measured vmax higher than the capillary prediction was taken as a further indication of PF. While PF was identified as a common process during infiltration, it was also temporally and spatially highly variable. We found a strong dependence of PF on the initial soil water content and the maximum rainfall intensity. Whereas a high rainfall intensity increased PF (NSR, vmax) as expected, most geologies and land covers showed the highest PF under dry initial conditions. Hence, we identified a strong seasonality of both NSR and vmax dependent on land cover, revealing a lower occurrence of PF during spring and increased occurrence during summer and early autumn, probably due to water repellency. We observed the highest fraction of NSR in forests on clay-rich soils (slate, marl). vmax ranged from 6 to 80640cmd-1 with a median of 120cmd-1 across all events and soil moisture profiles. The soils in the marl geology had the highest flow velocities, independent of land cover, especially between 30 and 50cm depth, where the clay content increased. This demonstrates the danger of treating especially clay soils in the vadose zone as a low-conductive substrate, as the development of soil structure can dominate over the matrix property of the texture alone. This confirms that clay content and land cover strongly influence infiltration and reinforce PF, but seasonal dynamics and flow initiation also have an important impact on PF. © 2019 BMJ Publishing Group. All rights reserved.
语种	英语
scopus关键词	Catchments; Clay; Fertilizers; Forestry; Geology; Groundwater flow; Moisture control; Rain; Sensor networks; Slate; Soil moisture; Soil surveys; Textures; Conductive substrates; Initial conditions; Large scale sensor network; Preferential flows; Rainfall intensity; Soil moisture profiles; Strong dependences; Temporal and spatial; Infiltration; experimental design; infiltration; land cover; landscape; precipitation intensity; preference behavior; preferential flow; seasonality; soil moisture; soil structure; soil water; spatiotemporal analysis; vadose zone; water content; Luxembourg [Benelux]; Luxembourg [Luxembourg (NTN)]
来源期刊	Hydrology and Earth System Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/159555
作者单位	Demand, D., Institute of Earth and Environmental Sciences, Hydrology, University of Freiburg, Freiburg, Germany; Blume, T., Section Hydrology, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany; Weiler, M., Institute of Earth and Environmental Sciences, Hydrology, University of Freiburg, Freiburg, Germany
推荐引用方式 GB/T 7714	Demand D.,Blume T.,Weiler M.. Spatio-temporal relevance and controls of preferential flow at the landscape scale[J],2019,23(11).
APA	Demand D.,Blume T.,&Weiler M..(2019).Spatio-temporal relevance and controls of preferential flow at the landscape scale.Hydrology and Earth System Sciences,23(11).
MLA	Demand D.,et al."Spatio-temporal relevance and controls of preferential flow at the landscape scale".Hydrology and Earth System Sciences 23.11(2019).