• 제목/요약/키워드: Atmospheric $SO_2$

검색결과 919건 처리시간 0.033초

ATMOSPHERIC REFRACTION EFFECTS ON LAMOST

  • SUN AIQUN;Hu JINGYAO
    • 천문학회지
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    • 제29권spc1호
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    • pp.397-398
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    • 1996
  • Large field spectrographs are severely influenced by atmospheric refraction. LAMOST is a large field multi-object spectroscopy telescope with $5^{\circ}$ field of view, f/5 focus ratio and 20m focal length. There will be 4000 fibers simultaneous on it's $\phi$1.75m focal plane. Here we discuss the atmospheric refraction effects on LAMOST in two hands. One is the effect of differential refraction across the field, another is the effect of atmospheric dispersion. According to the calculation, we find that: 1. The largest deviation from center within the field is 4.;32" during a 1.5-hour integration at $80^{\circ}$ declination. 2. The directions of deviation are complex, so the deviations can't be decreased by rotating the field. We also give out the atmospheric dispersions.

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대기확산의 수치모의에서 SST 효과 (SST Effect upon Numerical Simulation of Atmospheric Dispersion)

  • 이화운;원경미;조인숙
    • 한국대기환경학회지
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    • 제15권6호
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    • pp.767-777
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    • 1999
  • In the coastal region air flow changes due to the abrupt change of surface temperature between land and sea. So a numerical simulation for atmospheric flow fields must be considered the correct fields of sea surface temperature(SST). In this study, we used variables such as latent heat flux, sensible heat flux, short and long wave radiation of ocean and atmosphere which exchanged across the sea surface between atmosphere and ocean model. We found that this consideration simulated the more precise SST fields by comparing with those of the observated results. Simulated horizontal SST differences in season were 2.5~4$^{\circ}C$. Therefore we simulated the more precise atmospheric flow fields and the movement and dispersion of the pollutants with the Lagrangian particle dispersion model. In the daytime dispersion pattern of the pollutants emitted from ship sources moved toward inland, in the night time moved toward sea by land/sea breeze criculation. But air pollutants dispersion can be affected by inland topography, especially Yangsan and coastal area because of nocturnal wind speed decrease.

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Annular Denuder System을 이용한 수도권지역의 산성오염물질 및 $PM_{2.5}$ 성분농도 특성 (Characteristics of Acidic Air Pollutants and $PM_{2.5}$ Species in Seoul-Metropolitan Areas Using an ADS)

  • 강충민;이승일;조기철;안준영;최민규;김희강
    • 한국대기환경학회지
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    • 제15권3호
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    • pp.305-315
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    • 1999
  • The annular denuder system(ADS) was used to determine characteristics of acidic air pollutants and $PM_{2.5}$ species in Seoul-metropolitan areas. All measurements were done simultaneously in downtown(Kwanghwamun, Mullae, Chamshil, Ssangmun dongs) and outskirts(Puch n, Kuri cities) during four seasons. The samples were analyzed using ion chromatography for gas-phase matters(HCl, $HNO_2$, $HNO_3$ and $SO^2$) and particulate phase matters($Cl^-$, $NO^{2-}$, $NO_3^-$, $SO_4^{2-}$, $Na^+$, $NH_4^-$ and $Ca^{2+}$) and was measured fine particles($PM_{2.5}$). The seasonal mean concentrations of HCl, HNO2, HNO3 and SO2 in downtown and outskirt areas were very similar. All chemical species monitored from this study showed seasonal variations. Nitric acid(HNO3) and Nitrous acid(HNO2) were showed higher concentrations during the summer. $PM_{2.5}$, $SO_4^{2-}$, $NH_4^-$, $NO_3^-$ and $Cl^-$ in the particulate phase matters were higher levels during the winter months. The concentrations of these components were 54.8, 3.82, 2.49, 1.80 and 1.02$\mu\textrm{g}$/㎥, respectively.

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독도에서의 대기 background 농도 (Atmospheric Background Values at Dokdo Island, Korea)

  • 이동인
    • 한국수산과학회지
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    • 제28권1호
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    • pp.80-86
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    • 1995
  • 1991년 6월 7일-8일, 1992년 6월 25일-26일까지 약 2일 동안 대기중의 background 농도값을 알아보기 위하여 비오염 지역인 독도 정상에서 기상요소와 함께 가스 성분 $(SO_2,\;CO,\;NO_2,\;O_3)$ 및 입자성분을 채취하여 이를 분석하고, 또한 에어로졸의 형상과 성분 분석을 실시한 결과를 요약하면 다음과 같다. 1) 독도의 기상상태는 대체적으로 습도가 높은 해안지방의 특성을 가졌으며, 독도 정상 (해발 98m)에서의 대기 중의 시료 채취 결과, 가스상 물질인 $SO_2,\;CO,\;NO_2$$O_3$의 평균 농도 값은 대기 환경기준치에 크게 미달되는 2.3ppb, 5.57ppm, 6ppb 및 7ppb로써 상당히 좋은 대기질로 판단된다. 2) 부유입자상 물질의 농도 값은 $153{\mu}g/m^3$으로써 년평균값의 환경기준치보다 약간 상회하였지만 그 성분 분석결과, 대부분 입경이 크고 ($1{\mu}m$이상) Na, Cl과 같은 해염성분이 우세하였다. 따라서 대기 입자상 물질의 환경기준치 설정시 그 성분분석도 함께 고려되어야만 할 것으로 사료된다. 3) 독도는 해양에서의 대기질 평가를 위한 지점으로써 뿐만 아니라 기상학적 관측 자료를 얻기 위한 주요한 고정 관측점으로써도 이용될 수 있을 것으로 사료된다.

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수도권에서 아황산가스의 황산염으로 전환시 각 과정의 상대적 기여도 (The Relative Contribution of SO2-to-sulfate Conversion Processes over the Metropolitan Seoul Area)

  • 배수야;김용표
    • 한국대기환경학회지
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    • 제19권4호
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    • pp.451-465
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    • 2003
  • The major conversion processes of SO$_2$ to sulfate are reactions in gaseous, aqueous phase and on dust surface. Using the measurement data in Ganghwa, the background area of metropolitan Seoul Area, the relative contiribution of the conversion processes are estimated. Generally, aqueous cloud if the most important conversion path followed by dust surface, gas, and aqueous aerosol. Importance of conversion on dust surface increases for the dust storm period. The total conversion rate values over the metropolitan Seoul area are between 1.5 and 8.8$\times$10$^{-11}$ mole m$^{-3}$ air.

自動車에 의한 汚染物質 排出係數 및 排出量 算定에 관한 硏究 (Estimation of Emission Factor and Air Pollutant Emissions by Motor Vehicles)

  • 趙康來;金良均;董宗仁;嚴明道
    • 한국대기환경학회지
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    • 제3권1호
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    • pp.55-64
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    • 1987
  • Actual driving pattern of each motor vehicle type was measured and analyzed in Seoul area and vehicle emission rate was measured and traffic data were used to estimate vehicular emission factor and motor vehicle-related air pollutant emission. The analysis of contribution ratio of each vehicle type showed that LPG taxi's took 38.1% of total vehicular CO, gasoline passenger cars 37.5%, therefore, these cars are major sources of CO, gasoline passenger cars took 45.4% of total vehicular HC, motorcycles 25.3%, LPG taxi's 16.2%, so motorcycles can be said to play an important role in HC emission. For NOx, buses and trucks were thought to be major sources as buses took 36.8% and truck 26.4%. Diesel vehicles, on the other hand, took most $SO_2$ and particulate matter emission. Total emission from motor vehicles in Seoul was estimated to be 547 t/day of CO, 68t/day of HC, 163t/day of NOx, 18t/day of $SO_2$ and 19t/day of paticulate matter.

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부산지역에서의 대기흐름과 관련된 $SO_2$농도 3차원 수치모의 (A Three Dimensional Numerical Simulation of $SO_2$ Concentration in Relation with Atmospheric Flow in Pusan Area, Korea)

  • 장은숙;이화운
    • 한국환경과학회지
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    • 제6권4호
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    • pp.359-367
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    • 1997
  • The Characteristics of atmospheric flow and dispersion of air pollutants in the mountainous coastal area were studied using three-dimensional model by the combination of land/sea breezes and transport. It was then applied to Pusan city. As the urban area considered In this study is located in a mountainous coastal area, the atmospheric flow is strongly affected by the land/sea breezes and mountain/valley winds. The typical effects of land/sea breezes on the dispersion and the characteristics of pollutants movement in the region were analysed. The model has been proved to be an useful tool to prodict real time air pollutants transport as shown by the results of application studies In Pusan, Korea which Is an urbanized coastal area with mountainous topography. It was found that the pollutants are differently transported and concentrated as going Inland by the Influence of the sea breeze with topographic changes. By comparing the pollutants concentrations of the stimulated results with those of the observational results, It is shown that stimulated results in this study are in qualitative agreement with observational ones.

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