&lt;title&gt;Optical Properties Of Turbidity Standards&lt;/title&gt;

Ronald, J.; Zaneveld, V.; Spinrad, Richard W.; Bartz, Robert

doi:10.1117/12.958272

Cited by 11 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As recommend by Gibbs [36], Downing [37], Zaneveld et al [38] and Boss et al [20] among others, the calibration was conducted to match the electrical value of the photodetectors to the concentration of suspended sediments (g/L). The concentration of suspended sediments unit was chosen, but an equivalent procedure could be used to calibrate the output to other types of units.…”

Section: In-lab Calibrationmentioning

confidence: 99%

Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment

Matos

Faria

Martins

et al. 2019

Sensors

View full text Add to dashboard Cite

A cost-effective optical sensor for continuous in-situ monitoring of turbidity and suspended particulate matter concentration (SPM), with a production cost in raw materials less than 20 €, is presented for marine or fluvial applications. The sensor uses an infrared LED and three photodetectors with three different positions related to the light source—135º, 90º and 0º—resulting in three different types of light detection: backscattering, nephelometry and transmitted light, respectively. This design allows monitoring in any type of environment, offering a wide dynamic range and accuracy for low and high turbidity or SPM values. An ultraviolet emitter–receiver pair is also used to differentiate organic and inorganic matter through the differences in absorption at different wavelengths. The optical transducers are built in a watertight structure with a radial configuration where a printed circuit board with the electronic signal coupling is assembled. An in-lab calibration of the sensor was made to establish a relation between suspended particulate matter (SPM) or the turbidity (NTU) to the photodetectors’ electrical output value in Volts. Two different sizes of seashore sand were used (180 µm and 350 µm) to evaluate the particle size susceptibility. The sensor was tested in a fluvial environment to evaluate SPM change during sediment transport caused by rain, and a real test of 22 days continuous in-situ monitoring was realized to evaluate its performance in a tidal area. The monitoring results were analysed, showing the SPM change during tidal cycles as well as the influence of the external light and biofouling problems.

show abstract

Section: In-lab Calibrationmentioning

confidence: 99%

Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment

Matos

Faria

Martins

et al. 2019

Sensors

View full text Add to dashboard Cite

show abstract

“…The SPM Sensor was developed in a radial configuration, using one infrared backscattering channel (optical receiver placed at 135 • related to the emitter), one infrared nephelometric channel (optical receiver placed at 90 • related to the emitter), and one ultraviolet and one infrared transmitted light channels (optical receiver placed at 0 • related to the emitter). The use of multiples angles to measure turbidity allows a wide dynamic range and precision [25].…”

Section: Sensor Designmentioning

confidence: 99%

Design of a Multipoint Cost-Effective Optical Instrument for Continuous In-Situ Monitoring of Turbidity and Sediment

Matos

Faria

Martins

et al. 2020

Sensors

View full text Add to dashboard Cite

A cost-effective optical instrument for continuous in-situ monitoring applications is presented. With a production cost in raw materials of 38 €, a power consumption of 300 A in sleep mode and 100 mA in active mode (5 ms reading), and a capacity to monitor turbidity and sedimentary displacement at eight different depths in the water column, the sensor was developed for sediment monitoring in coastal areas. Due to the extent and dynamics of the processes involved in these areas, observations require a wide spatial and temporal resolution. Each of the eight monitoring nodes uses one infrared backscatter channel, to estimate turbidity and sediment concentration, and one ultraviolet with one infrared transmitted light channels to distinguish organic/inorganic composition of the suspended material load. An in-lab calibration was conducted, using formazine to correlate turbidity with the electronic outputs of the instrument. An analysis of the influence of external light sources and correction techniques were performed. Moreover, an in-lab experiment was conducted to study the behaviour of the sensor-to-sediment transport, wash load and sediment accumulation. The device was deployed, with a water level sensor, in an estuarine area with high sediment dynamics. The monitoring data were analysed, showing the potential of the device to continuously monitor turbidity, sediment processes, and distinguish between organic and inorganic matter, at the different depths in the water column.

show abstract

Clarifying water clarity: A call to use metrics best suited to corresponding research and management goals in aquatic ecosystems

Turner

Fall

Friedrichs

2022

Limnol Oceanogr Letters

View full text Add to dashboard Cite

Water clarity is a subjective term and can be measured multiple ways. Different metrics such as light attenuation and Secchi depth vary in effectiveness depending on the research or management application. In this essay, we argue that different questions merit different water clarity metrics. In coastal and inland waters, empirical relationships to estimate light attenuation can yield clarity estimates that either under-or overestimate the underwater light climate for restoration goals, such as potential habitat available for submerged aquatic vegetation. Best practices in reporting water clarity measurements include regionally specific, temporally representative calibrations and communicating the metric that was actually measured. An intentional choice of the water clarity metric best suited to the research or management question yields the most useful results.The term "water clarity" is inherently ambiguous. Water clarity generally refers to the distance that light penetrates through water, as well as the visibility of objects through water. In lakes, rivers, estuaries, coastal zones, and the open ocean, water clarity is an essential measurement for monitoring programs and a wide variety of research applications. For example, water clarity is used to assess habitat quality for submerged aquatic vegetation (SAV), to study visual predation, and to model primary production. Water clarity is measured using multiple methods, some focused on the depth of light penetration, some based on the depth of object visibility, and others based on the amounts of components present (Fig. 1).General metrics presented here include: Secchi disk depth (Z SD ) (Secchi and Cialdi 1866; Tyler 1968; Preisendorfer 1986), the downwelling and scalar light attenuation coefficients of photosynthetically active radiation (K d (PAR) and K o (PAR)) (Kirk 1994), turbidity (Zaneveld et al. 1980Davies-Colley and Smith 2001;Sampedro and Salgueiro 2015;Eidam et al. 2022), and beam attenuation (Bishop 1999). In this paper, the terms K d and K o will refer to K d (PAR) and K o (PAR). Z SD , K o , and K d are apparent optical properties, descriptors of water bodies that depend on both the substances present and the light field (Mobley 2022). Component-based metrics include colored dissolved organic matter (CDOM) commonly measured by its light absorption (aCDOM; m À1 ) (Green and Blough 1994) or

show abstract

<title>Optical Properties Of Turbidity Standards</title>

Cited by 11 publications

References 0 publications

Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment

Development of a Cost-Effective Optical Sensor for Continuous Monitoring of Turbidity and Suspended Particulate Matter in Marine Environment

Design of a Multipoint Cost-Effective Optical Instrument for Continuous In-Situ Monitoring of Turbidity and Sediment

Clarifying water clarity: A call to use metrics best suited to corresponding research and management goals in aquatic ecosystems

Contact Info

Product

Resources

About