• Title/Summary/Keyword: TGM

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IDENTIFICATION OF POSSIBLE MERCURY SOURCES AND ESTIMATION OF MERCURY WET DEPOSITION FLUX IN LAKE ONTARIO FROM LAKE ONTARIO ATMOSPHERIC DEPOSITION STUDY (LOADS)

  • Han, Young-Ji
    • Environmental Engineering Research
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    • v.10 no.6
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    • pp.306-315
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    • 2005

  • Total gas phase mercury (TGM) concentrations and event wet-only precipitation for Hg were collected for nine months (from April, 2002 to Dec., 2002) at Sterling, NY on the shoreline of Lake Ontario. TGM concentrations measured in this study ($3.02{\pm}2.14\;ng/m^3$) were in somewhat high range compared to other background sites. Using simplified quantitative transport bias analysis (SQTBA) possible sources affecting high Hg concentration in Sterling was identified, and they are coal-fired power plants located in southern NY and Pennsylvania. Wet deposition measured at Mercury Deposition Network (MDN) sites including Pt. Petre and Egbert, ON were compared with data obtained at the Sterling to estimate the total mercury wet deposition flux to Lake Ontario. The wet deposition flux was calculated to be the highest at the Sterling site ($7.94\;{\mu}g/m^2$ from April, 2002 to Dec. 2002) and the lowest at the Egbert ($3.92\;{\mu}g/m^2$), due to the both the difference in precipitation depth and Hg concentration in the precipitation. The deposition measured at the Sterling site is similar to Lake Michigan deposition of $6-14\;{\mu}g/m^2$ (converted for ninth months) measured for Lake Michigan Mass Balance Study (LMMBS).

  • https://doi.org/10.4491/eer.2005.10.6.306 인용 PDF KSCI

Source Identification of Gaseous Mercury Measured in New York State Using Hybrid Receptor Modeling (수용원 모델을 사용한 대기 중 수은 오염원의 위치 추정에 대한 연구)

  • Han Young-Ji
    • Journal of Korean Society for Atmospheric Environment
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    • v.22 no.2
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    • pp.179-189
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    • 2006

  • Ambient gas phase mercury concentrations including elemental mercury ($Hg^0$) were measured at the Potsdam, Stockton, and Sterling sites in NY from 2000 to 2003. Also, concentrations of ambient reactive gaseous mercury (RGM; $Hg^{2+}$) were measured at the Potsdam site during one year. The contribution of RGM($4.2{\pm}6.4pg/m^3$) was about $0.2{\sim}3%$ of the total gas phase mercury concentration measured (TGM: $1.84{\pm}1.24,\;1.83{\pm}0.32,\;3.02{\pm}2.14ng/m^3$ in Potsdam. Stockton, and Sterling, respectively) at the receptor sites. Potential Source Contribution Function (PSCF), a hybrid receptor modeling incorporating backward trajectories was performed to identify source areas of TGM. Using PSCF, southern New York, North Carolina, and eastern Massachusetts were identified as important source areas in the United States, while the copper smelters and waste incinerators located in eastern Quebec and Ontario were determined to be significant sources in Canada. The Atlantic Ocean was suggested to be a possible mercury source. PSCF incorporating back-dispersion and deposition was applied for RGM , as well as PSCF based on 2-days back-trajectories. Two different approaches yielded considerably different results, primarily due to the consideration of dispersion rather than deposition. Using back-trajectory based PSCF, eastern Ohio, southern New York, and southern Pennsylvania where large coal -fired power plants area located were identified as the large sources in US. Metallurgical industry located in eastern Quebec was resolved as well. From the result of back-dispersion and deposition based PSCF, Pennsylvania, mining facilities around Lake Superior, Toronto, Boston, MA, Quebec, and coal power plants in NY were identified to be the significant source areas for Potsdam site.

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Improved Height Determination Using a Correction Surface by Combining GNSS/Leveling Co-points and Thailand Geoid Model 2017

  • Dumrongchai, Puttipol;Buatong, Titin;Satirapod, Chalermchon;Yun, Seonghyeon
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.40 no.4
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    • pp.305-313
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    • 2022

  • The evolution of the GNSS (Global Navigation Satellite System) technology has enhanced positioning performance in terms of positioning accuracy and time efficiency. The technology makes it possible to determine orthometric heights at a few centimeter accuracies by transforming accurate ellipsoid heights if an accurate geoid model has been employed. This study aims to generate a correction surface using GNSS/leveling co-points and a local geoid model, Thailand Geoid Model 2017 (TGM2017), through the Kriging interpolation method in a small local area. Combining the surface and TGM2017 significantly improves height transformation with the 1-cm RMSE (Root Mean Square Error) fit of 10 GNSS/leveling reference points and a mean offset of +0.1 cm. The evaluation of the correction surface at 5 GNSS/leveling checkpoints shows the RMSE of 1.0 cm, which is 82.6 percent of accuracy improvements. The GNSS leveling method can possibly be used to replace a conventional leveling technique at a few centimeter uncertainties in the case of small areas with clear-sky and high satellite visibility environments.

  • https://doi.org/10.7848/ksgpc.2022.40.4.305 인용 PDF KSCI