• 제목/요약/키워드: land-sea breeze

검색결과 108건 처리시간 0.079초

해석학적모델을 이용한 하계 대구지방의 열적저기압 형성에 관한 연구 (On the Thermal Low-pressure Onset using Analytical Model around Daegu in Summer)

  • 김해동;정우식
    • 한국환경과학회지
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    • 제11권10호
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    • pp.1133-1140
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    • 2002
  • The growth and extent of the local pressure field at any point is of primary importance as it supplies the driving force for the local wind circulation which causes a medium-range transport of air pollutants. The local pressure field is produced by the variation of temperature in the lower layers of the atmosphere, and is called the thermal wave. The thermal wave is influenced by the difference in the diurnal variations between two regions with different surface condition, for example land and sea. This difference produces the land- and sea-breeze phenomenon, and brings corresponding variations in the form of the thermal wave. Daytime temperature over the inland area (Daegu) was higher than that of the coastal area (Busan). The temperature difference reached about 5~6$^{\circ}C$ in the late afternoon(30-31 May 1999). The low pressure system of Daegu was most fully developed at the time. In this study, we investigated the possibility of thermal low onset around Daegu in summer with an analytical model. The topography effect was neglected in the model. We could predict a thermal low-pressure of about 3.4hPa at Daegu with wide flat land surface, when the inland area is about 6K warmer than the coastal area temperature. The pressure decrease is somewhat less than the observed value(4~5 hPa).

산악연안지역에서 내부중력파와 해륙풍순환 영향하의 대기오염농도 (Atmospheric Pollutant Concentrations under the Influences of Internal Gravity Wave and Sea-Land Breeze Circulations in the Mountainous Coastal Regions)

  • Hyo Choi;Joon Choi
    • International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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    • 제23권1호
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    • pp.18-33
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    • 1995
  • 동쪽 연안지역에서 큰 경사를 갖인 산맥위를 흘러가는 종관규모의 서풍하에서 내부 중력파와 같은 강한 하강폭풍이 산의 후면에서 발생되어 진다. 주간에 해양에서 내륙으로 향하는 중규모의 열적 강화에 의해 유도되는 해풍순환이 동쪽으로 향하는 내부중력파에 기인하여 연안의 앞바다까지만 국한된다. 따라서 연안해 근처의 표층풍은 외해나 내륙의 위치에서보다 상대적으로 더 약하다. 명백하게 서풍의 내부중력파순환파 해면 근처에서 동풍 및 상층에서 서풍을 갖는 해풍순환과 같은 두개의 상이한 종류의 대기순환이 뚜렷하게 나타났다. 이런 상황에서 강릉시에서의 대기오염물질은 반대 방향의 두개의 상이한 순환에 의해 갇히게 되고 부유분진과 오존의 고농도가 초래되었다. 야간에 육지에서 연안해로 향하는 중규모의 육풍은 기존의 동쪽으로 향하는 하강풍과 협력하여 연안지역에서 서풍의 더욱 강화를 유도할 수 있었다. 산쪽에서 연안해로 향하여 부는 강한 표층풍에 의해 조절되는 부유분진의 농도는 추간의 경우보다 야간에 비교적 더 높았으며, 상층대기로 부터 지표면으로 오존의 하양수송에 기인하여 오존의 농도가 주간보다 야간에 매우 높았다. 결과로 바람폭풍하의 산악연안지역에서 대기오염농도는 바람푹풍 전.후보다 더 높았다.

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남한 지역에서 여름철 맑은 날의 대기 오염물 확산에 대한 수치적 연구 (A Numerical Study of Atmospheric Pollutant Dispersionon over South Korea on Sunny Summer Days)

  • 이태영;김승범
    • 한국환경과학회지
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    • 제5권4호
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    • pp.411-427
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    • 1996
  • A Lagrangian dispersion model has been developed to study the transport of atmospheric pollutants over the southern Korean peninsula on sunny summer days. A mesoscale atmospheric model has been employed to provide the wind fields and information for turbulent diffusion for the calculation of trajectories using a conditioned particle technique. The model has been applied to the simulation of the transport of atmospheric pollutants emitted from five sources in the coastal locations under various synoptic scale winds. Under calm synoptic scale condition, the particles emitted during daytime are mixed vertically and transported toward inland by sea-breeze, according to the model simulation. The particles are then transported upward at she sea-breeze front or by the upward motion over the mountain, and some particles show tendency of returning toward the coast by the return flow of the sea-breeze circulation. The particles are found to remain over the peninsula throughout the integration period under calm synoptic scale condition. When there is westerly synoptic scale winds the particles emitted in the west coast can reach the east coast within a day of faster depending on the speed. With a synoptic scale southerly wind of 5 m/s, most of the particles from the fine sources are advected toward inland during daytime. During nighttime, significant portion of particles released in the west coast remains over the land, while most particles released in the east coast move toward the sea to the east of the middle peninsula.

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IEC 61400 풍력표준을 적용한 제주도 김녕 난류강도 특성분석 (Analysis on Turbulence Intensity Characteristics at Gimnyeong, Jejudo by Applying IEC 61400 Wind Turbine Standards)

  • 김현구;정태윤;장문석
    • 한국태양에너지학회 논문집
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    • 제30권6호
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    • pp.59-65
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    • 2010
  • Analysis on turbulence intensity profile depending on wind speed is an important process to set up design condition of wind turbine in terms of fatigue load. This paper tests goodness of fit of turbulence intensity empirical equations suggested by the IEC 61400 Standards with Jejudo Gimnyeong met-tower measurement, which is erected at a seashore. Therefore sea breeze and land breeze coexist. Sea breeze case showed apparent increasing trend of turbulence intensity in a high wind speed regime due to increase of sea surface roughness. However, neither inland wind turbine standard IEC 61400-1 nor offshore wind turbine standard IEC 61400-3 fit such a trend adequately. On the other hand, the modified empirical equation of turbulence intensity of IEC 61400-3 derived from Germany FINO1 application study by considering turbulence intensity behavior in a high wind speed regime showed good agreement with the measurement. Therefore, we can reconfirm and conclude that IEC 61400-3 Ed.1 legislated in 2009 needs to be modified.

중/도시규모 기상모델을 이용한 고층건물군이 연안도시기상장에 미치는 영향 수치모델링 (Numerical Modeling for the Effect of High-rise Buildings on Meteorological Fields over the Coastal Area Using Urbanized MM5)

  • 황미경;오인보;김유근
    • 한국대기환경학회지
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    • 제28권5호
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    • pp.495-505
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    • 2012
  • Modeling the effects of high-rise buildings on thermo-dynamic conditions and meteorological fields over a coastal urban area was conducted using the modified meso-urban meteorological model (Urbanized MM5; uMM5) with the urban canopy parameterization (UCP) and the high-resolution inputs (urban morphology, land-use/land-cover sub-grid distribution, and high-quality digital elevation model data sets). Sensitivity simulations was performed during a typical sea-breeze episode (4~8 August 2006). Comparison between simulations with real urban morphology and changed urban morphology (i.e. high-rise buildings to low residential houses) showed that high-rise buildings could play an important role in urban heat island and land-sea breeze circulation. The major changes in urban meteorologic conditions are followings: significant increase in daytime temperature nearly by $1.0^{\circ}C$ due to sensible heat flux emitted from high density residential houses, decrease in nighttime temperature nearly by $1.0^{\circ}C$ because of the reduction in the storage heat flux emitted from high-rise buildings, and large increase in wind speed (maximum 2 m $s^{-1}$) during the daytime due to lessen drag-force or increased gradient temperature over coastal area.