气候变化领域集成服务门户(CCPortal): Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations

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DOI	10.5194/hess-22-1767-2018
	Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations
	Voichick N.; Topping D.J.; Griffiths R.E.
发表日期	2018
ISSN	1027-5606
起始页码	1767
结束页码	1773
卷号	22 期号:3
英文摘要	Turbidity, a measure of water clarity, is monitored for a variety of purposes including (1) to help determine whether water is safe to drink, (2) to establish background conditions of lakes and rivers and detect pollution caused by construction projects and stormwater discharge, (3) to study sediment transport in rivers and erosion in catchments, (4) to manage siltation of water reservoirs, and (5) to establish connections with aquatic biological properties, such as primary production and predator-prey interactions. Turbidity is typically measured with an optical probe that detects light scattered from particles in the water. Probes have defined upper limits of the range of turbidity that they can measure. The general assumption is that when turbidity exceeds this upper limit, the values of turbidity will be constant, i.e., the probe is pegged; however, this assumption is not necessarily valid. In rivers with limited variation in the physical properties of the suspended sediment, at lower suspended-sediment concentrations, an increase in suspended-sediment concentration will cause a linear increase in turbidity. When the suspended-sediment concentration in these rivers is high, turbidity levels can exceed the upper measurement limit of an optical probe and record a constant pegged value. However, at extremely high suspended-sediment concentrations, optical turbidity probes do not necessarily stay pegged at a constant value. Data from the Colorado River in Grand Canyon, Arizona, USA, and a laboratory experiment both demonstrate that when turbidity exceeds instrument-pegged conditions, increasing suspended-sediment concentration (and thus increasing turbidity) may cause optical probes to record decreasing false turbidity values that appear to be within the valid measurement range of the probe. Therefore, under high-Turbidity conditions, other surrogate measurements of turbidity (e.g., acoustic-Attenuation measurements or suspended-sediment samples) are necessary to correct these low false turbidity measurements and accurately measure turbidity. © 2018 Copernicus GmbH. All rights reserved.
语种	英语
scopus关键词	Catchments; Probes; Reservoirs (water); River pollution; Rivers; Sediment transport; Sedimentation; Sediments; Turbidity; Water pollution; Background conditions; Biological properties; Grand Canyon , Arizona; Laboratory experiments; Predator-prey interaction; Stormwater discharges; Suspended sediment concentrations; Turbidity measurements; Suspended sediments; catchment; concentration (composition); discharge; experimental study; optical method; physical property; probe; sediment transport; siltation; suspended sediment; turbidity; Arizona; Colorado River [North America]; Grand Canyon; United States
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/160084
作者单位	Voichick, N., U.S. Geological Survey, Grand Canyon Monitoring and Research Center, 2255 N. Gemini Dr, Flagstaff, AZ 86001, United States; Topping, D.J., U.S. Geological Survey, Grand Canyon Monitoring and Research Center, 2255 N. Gemini Dr, Flagstaff, AZ 86001, United States; Griffiths, R.E., U.S. Geological Survey, Grand Canyon Monitoring and Research Center, 2255 N. Gemini Dr, Flagstaff, AZ 86001, United States
推荐引用方式 GB/T 7714	Voichick N.,Topping D.J.,Griffiths R.E.. Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations[J],2018,22(3).
APA	Voichick N.,Topping D.J.,&Griffiths R.E..(2018).Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations.Hydrology and Earth System Sciences,22(3).
MLA	Voichick N.,et al."Technical note: False low turbidity readings from optical probes during high suspended-sediment concentrations".Hydrology and Earth System Sciences 22.3(2018).