Estimating quality of indirect measurements of sea water sound velocity by CTD data

Grekov, A.N.; Grekov, N.A.; Sychov, E.N.

doi:10.1016/j.measurement.2021.109073

Cited by 10 publications

(5 citation statements)

References 14 publications

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“…The separated water was measured with a Cond 3310 m equipped with a TetraCon 325 probe to determine the bulk practical salinity. The reference salinity was then calculated using Equation (1) from [40]. Salinities of the clean water samples were measured with an Orion Star A212-Thermo Scientific conductivity meter, and the reference salinity was subsequently calculated.…”

Section: Physical Sample Collectionmentioning

confidence: 99%

Assessment of C-Band Polarimetric Radar for the Detection of Diesel Fuel in Newly Formed Sea Ice

Hicks,

Zabihi Mayvan,

Asihene

et al. 2024

Remote Sensing

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There is a heightened risk of an oil spill occurring in the Arctic, as climate change driven sea ice loss permits an increase in Arctic marine transportation. The ability to detect an oil spill and monitor its progression is key to enacting an effective response. Microwave scatterometer systems may be used detect changes in sea ice thermodynamic and physical properties, so we examined the potential of C-band polarimetric radar for detecting diesel fuel beneath a thin sea ice layer. Sea ice physical properties, including thickness, temperature, and salinity, were measured before and after diesel addition beneath the ice. Time-series polarimetric C-band scatterometer measurements monitored the sea ice evolution and diesel migration to the sea ice surface. We characterized the temporal evolution of the diesel-contaminated seawater and sea ice by monitoring the normalized radar cross section (NRCS) and polarimetric parameters (conformity coefficient (μ), copolarization correlation coefficient (ρco)) at 20° and 25° incidence angles. We delineated three stages, with distinct NRCS and polarimetric results, which could be connected to the thermophysical state and the presence of diesel on the surface. Stage 1 described the initial formation of sea ice, while in Stage 2, we injected 20L of diesel beneath the sea ice. No immediate response was noted in the radar measurements. With the emergence of diesel on the sea ice surface, denoted by Stage 3, the NRCS dropped substantially. The largest response was for VV and HH polarizations at 20° incidence angle. Physical sampling indicated that diesel emerged to the surface of the sea ice and trended towards the tub edge and the polarimetric scatterometer was sensitive to these physical changes. This study contributes to a greater understanding of how C-band frequencies can be used to monitor oil products in the Arctic and act as a baseline for the interpretation of satellite data. Additionally, these findings will assist in the development of standards for oil and diesel fuel detection in the Canadian Arctic in association with the Canadian Standards Association Group.

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Section: Physical Sample Collectionmentioning

confidence: 99%

Assessment of C-Band Polarimetric Radar for the Detection of Diesel Fuel in Newly Formed Sea Ice

Hicks,

Zabihi Mayvan,

Asihene

et al. 2024

Remote Sensing

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“…This device was calibrated with a calibration standard (0.01 mol/L KCl) for conductivity cells. The reference salinity was calculated from the measured practical salinity using Equation (8), where S R is reference salinity (g/kg), and S P is practical salinity (unitless) [39]. S R = 1.00472 * S P (8)…”

Section: Sample Processingmentioning

confidence: 99%

Monitoring Diesel Spills in Freezing Seawater under Windy Conditions Using C-Band Polarimetric Radar

Zabihi Mayvan,

Asihene,

Desmond

et al. 2024

Remote Sensing

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The risk of oil spills in the Arctic is growing rapidly as anthropogenic activities increase due to climate-driven sea ice loss. Detecting and monitoring fuel spills in the marine environment is imperative for enacting an efficient response to mitigate the risk. Microwave radar systems can be used to address this issue; therefore, we examined the potential of C-band polarimetric radar for detecting diesel fuel in freezing seawater under windy environmental conditions. We present results from a mesocosm experiment, where we introduced diesel fuel to a seawater-filled cylindrical tub at the Sea-ice Environmental Research Facility (SERF), University of Manitoba. We characterized the temporal evolution of the diesel-contaminated seawater and sea ice by monitoring the normalized radar cross section (NRCS) and polarimetric parameters (i.e., copolarization ratio (Rco), cross-polarization ratio (Rxo), entropy (H), mean-alpha (α), conformity coefficient (μ), and copolarization correlation coefficient (ρco)) at 20° and 25° incidence angles. Three stages were identified, with notably different NRCS and polarimetric results, related to the thermophysical conditions. The transition from calm conditions to windy conditions was detected by the 25° incidence angle, whereas the transition from open water to sea ice was more apparent at 20°. The polarimetric analysis demonstrated that the conformity coefficient can have distinctive sensitivities to the presence of wind and sea ice at different incidence angles. The H versus α scatterplot showed that the range of distribution is dependent upon wind speed, incidence angle, and oil product. The findings of this study can be used to further improve the capability of existing and future C-band dual-polarization radar satellites or drone systems to detect and monitor potential diesel spills in the Arctic, particularly during the freeze-up season.

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“…CTDs are used to identify temperature and salinity anomalies (Dickson et al, 1988), quantify saltand freshwater admixture and stratification in estuarine systems (Cloern et al, 2017), and identify and track ocean currents (Johnson et al, 2002). CTDs can also be used to detect the heat signatures of hydrothermal vents (Connelly et al, 2012), create sound velocity profiles for calibrating sonar (Grekov et al, 2021), and aid in the acoustic tracking of fish and other ocean wildlife (Roquet et al, 2017). Additionally, CTD casts can be helpful in finding undocumented wastewater discharges (DiGiacomo et al, 2004), identifying suitable regions for aquaculture (Longdill et al, 2008), detecting saltwater inundation in aquifers (Cantelon et al, 2022), and assessing changes following intense storms or heavy rains (Li et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

The OpenCTD: A Low-Cost, Open-Source CTD for Collecting Baseline Oceanographic Data in Coastal Waters

Thaler,

Sturdivant,

Neches

et al. 2024

oceanog

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CTDs, devices that measure salinity (via conductivity), temperature, and depth in the ocean, are essential for almost all marine scientific research, whether oceanography, ecology, conservation, or management. But CTDs are often cost-prohibitive, making this essential tool of ocean science inaccessible to the majority of ocean knowledge seekers. The OpenCTD is a low-cost, open-source oceanographic instrument, built from relatively accessible components, that allows ocean knowledge seekers to collect data on salinity, temperature, and depth in waters as deep as 140 m, with depth accurate to <1 cm, temperature to ±0.1°C, and a salinity error rate of 1%, with a 90% response time of 1 second. The OpenCTD is an open, adaptable platform that allows users to integrate other sensors (e.g., dissolved oxygen, pH) to fit their specific needs or questions. The utility of the OpenCTD for both STEM education and community oceanography is demonstrated in real-world case studies. The OpenCTD offers researchers, community groups, educators, managers, and other ocean knowledge seekers the ability to collect baseline data about their local waters at a fraction of the cost of commercial alternatives and, for most use cases, with comparable data quality.

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Estimating quality of indirect measurements of sea water sound velocity by CTD data

Cited by 10 publications

References 14 publications

Assessment of C-Band Polarimetric Radar for the Detection of Diesel Fuel in Newly Formed Sea Ice

Assessment of C-Band Polarimetric Radar for the Detection of Diesel Fuel in Newly Formed Sea Ice

Monitoring Diesel Spills in Freezing Seawater under Windy Conditions Using C-Band Polarimetric Radar

The OpenCTD: A Low-Cost, Open-Source CTD for Collecting Baseline Oceanographic Data in Coastal Waters

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