• Title, Summary, Keyword: salinity plumes

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Numerical and laboratory investigations of electrical resistance tomography for environmental monitoring

  • Heinson Tania Dhu Graham
    • Geophysics and Geophysical Exploration
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    • v.7 no.1
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    • pp.33-40
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    • 2004
  • Numerical and laboratory studies have been conducted to test the ability of Electrical Resistance Tomography-a technique used to map the electrical resistivity of the subsurface-to delineate contaminant plumes. Two-dimensional numerical models were created to investigate survey design and resolution. Optimal survey design consisted of both downhole and surface electrode sites. Resolution models revealed that while the bulk fluid flow could be outlined, small-scale fingering effects could not be delineated. Laboratory experiments were conducted in a narrow glass tank to validate theoretical models. A visual comparison of fluid flow with ERT images also showed that, while the bulk fluid flow could be seen in most instances, fine-scale effects were indeterminate.

Continuous Near-field Mixing with Variable Oceanic Conditions (해양수리특성의 변화를 고려한 연속적 근역혼합거동)

  • Kang See Whan;Kim Young Do;Lee Ho Jin;Kim Sang Ik;Han Sung Dae
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.4 no.4
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    • pp.12-20
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    • 2001
  • The temporal variability in near-field mixing characteristics of discharging plumes in oceanic environment was investigated using the time series data of the buoyant jet parameters. Based on the currents and density profiles observed in Masan outfall site and effluent discharge flowrates for 63days of summer season, the temporal variabilities and those occurrence frequency were obtained by line plume equations. The results show that wide range of variability in Masan outfall's mixing characteristics was found due to the temporal changes of effluent flowrates and ambient oceanic conditions. The near-field dilution was in the range of 30~71 with the averaged dilution of 34, which was a good agreement with field measurements of salinity deficit. The length of mixing zone was in the range of 5.4~36.2 m with the average of 9.5 m, and the plume rise height was in the range of 8.1~10.2 m with the average of 8.9 m. However, only the 30~44% of the whole results are higher than the averages, which indicates the necessity of this frequency analysis with the continuously measured data for designing and managing the ocean outfall system.

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Evidence for Hydrothermal Plume in Manus Basin, SW Pacific: Distribution of Transparency and Hydrogen Sulfide (남서태평양 마누스분지 해역의 열수 plume 증거: 투명도 및 황화수소 분포)

  • Lee, Kyeong-Yong;Park, Yong-Chul;Son, Seung-Kyu
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.5 no.4
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    • pp.363-373
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    • 2000
  • To understand and investigate chemical characteristics of thermal environment in the southwestern Paciflc, we have measured hydrological and chemical parameters such as temperature, salinity, transparency, pH, nutrients and hydrogen sulfide (H$_2$S). Samples were collected with CTD-casting at 12 station, in Manus Basin including PACMANUS, DESMOS and Susu Knolls, Hydrothermal systems consist of circulation zones where seawater interacts with rock, thereby changing chemical and physical characteristics of both the seawater and the rock. The altered seawater, called hydrothermal fluid, is injected back into the ocean from the hydrothermal vent fields and forms hydrothermal plumes. Consequently, we detected hydrothermal plume with transparency and sulfide anomalies at PACMANUS and Susu Knolls. Sulfide, as geochemical tracer of hydrothermal plume, ranged 0-3.31 ${\mu}$M, and averaged 0.63 ${\mu}$M in the study area. The height, flux and activity of the plume are affected by circulations in the deep water and the spread of plume follows along the isopycnal surface. Therefore the observed H$_2$S anomaly can provide important clue for the source location and it appears that the targestsource in the PACMANUS is aligned in the north-south direction.

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