• 제목/요약/키워드: Wind circulation

검색결과 329건 처리시간 0.026초

2006년 봄철 광양만 해류의 구조와 변동 (Current Structure and Variability in Gwangyang Bay in Spring 2006)

  • 이재철;김정창
    • 한국해양학회지:바다
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    • 제12권3호
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    • pp.219-224
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    • 2007
  • 광양만의 순환을 이해하기 위하여 2006년 봄철에 수심이 가장 깊은 두 지점을 선정하여 ADCP가 장착된 모니터링 부표 2대를 이용하여 유속관측을 하였다. 두 지점에서 공통적으로 북향류가 지배적인데, 이는 서쪽의 남향류를 동반하는 반시계 방향의 순환 이 있음을 뒷받침 하고 있다. 남쪽에서는 14 m 수심에서 유향이 반전되는 2층 구조가 뚜렷하며 저층의 북향류는 바닥에 가까운 36 m 수심까지 증가한다. 북쪽 지점에서는 북향류가 더욱 강해져서 북쪽의 단면적 감소에 따른 해류의 가속 효과가 있으며 상층부에서도 북향류가 우세하다. EOF 분석을 통한 연직구조에 있어서 첫 번째 모드는 북쪽 부표에서 전체 분산의 74%인데 비하여 남쪽 부표에서는 67%로 감소하고 상대적으로 2층 구조의 비중이 크다. 반시계 방향의 순환과 관련된 북향류의 전형적인 유속은 약 10 cm/s이다. 여기에 중첩되는 변동성으로서 국지적인 바람의 영향은 거의 받지 않는 반면에 동-서 방향의 바람에 의한 외해의 에크만 수송과 관련된 비국지적 영향은 주로 풍속이 강할 경우에 나타난다.

중규모 수치 모델을 이용한 대청 호수 주변의 국지 순환 모의 (Numerical Simulation of Local Circulation Over the Daechung Lake Area by Using the Mesoscale Model)

  • 변재영;최영진;서범근
    • 한국지구과학회지
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    • 제30권4호
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    • pp.464-477
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    • 2009
  • 호수에 의한 국지 순환의 영향을 조사하기 위하여 대청호수 주변에 대하여 수치 실험을 수행하고 국지 순환의 형태를 연구하였다. WRF 모델로부터 예보된 지상 기온은 관측보다 작으며, 풍속은 모델에서 관측보다 강하게 모의됨을 보였다. 호수 주변의 국지 순환은 호수와 주변 지면과의 열적 차이에 의해 발생하는 호수풍이 특징적이었다. 대청호수에서는 호수풍이 09 LST에 발생하며, 15 LST에 최대를 보이고 18 LST에 소멸하였다. 수치 모의된 연직 순환의 높이는 1,200m를 나타냈다. 비습의 분포는 낮 시간동안 호수풍 순환에 의해 호수위의 습윤한 공기의 내륙 이동으로 주위 지면에서 증가함을 보였다. 호수를 제거한 민감도 실험에서 호수가 존재할 때 주위 지면 온도가 감소함을 보였다. 호수 지표이용도를 초원으로 변경하였을 때 호수 주변의 기상관측소에서 풍속은 증가하였다. 수치실험은 호수로부터 발생된 호수풍 순환이 주위 대기경계층 기상에 영향을 주고 있음을 지시한다.

영일만 순환류 발생구조와 해황 특성 (Development Mechanism of Circulation Current and Oceanographic Characteristics in Yeongil Bay)

  • 윤한삼;이인철
    • 한국해양환경ㆍ에너지학회지
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    • 제8권3호
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    • pp.140-147
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    • 2005
  • 본 연구는 영일만 수괴의 만내 연안수와 동해 고유수와의 상호관련성과 만내 해수순환류 발생 메카니즘에 대해서 고찰하고자 하였다. 영일만 인근 동해 고유수는 평균수온 $12.2{\sim}18.4^{\circ}C$, 평균염분 $33.32{\sim}34.43$ PSU 인 것으로 나타났으며, 스펙트럼 해석결과를 통해 만내 연안수와 동해 고유수는 서로 일정한 주기성을 가지고 있으며, 표층과 저층 모두 약 0.84-0.91년, 1.84년의 주기를 나타내었다. 영일만에 출현하는 바람은 동계를 제외하고 대체로 SW와 NE방향의 왕복성 풍향을 나타내며 동계의 경우에는 SW방향의 풍향이 주로 출현하며, 이는 영일만내 수괴거동에 크게 영향을 미칠 것으로 판단된다. 영일만내에서의 하구 해수순환류는 표층에서 형산강 담수의 외해로의 유출과 저층에서 저온-고염의 동해 고유수가 유입되는 현상이 뚜렷하며, 이는 수괴가 안정되는 봄부터 시작하여 여름에 가장 뚜렷하게 나타나며, 그 발생주기는 단주기변동으로 약 10일정도의 주기를 가진다. 이러한 해수의 수평 연직순환류는 조석영향이 미약한 영일만의 경우 내만의 오염물질을 외해로 수송하는 큰 역할을 담당할 것으로 판단된다.

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難聽의 原因, 症狀, 治法에 對한 硏究;中醫雜誌를 中心으로 (A Study on causes and remedies of hearing disturbance in chinese medical journals)

  • 김성배;김종한;임규상
    • 한방안이비인후피부과학회지
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    • 제7권1호
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    • pp.35-51
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    • 1994
  • This is the study on causes and remedies of hearing disturbance in chinese medical journals(1991-1993). The results were as follows. 1. The causes of sudden deafness(突發性耳聾) were usually fire in the liver(肝火).phlegmatic fire(痰火), deficiency of the vital function and essence of the kidney(腎虛), blood stasis or sludge due to stagnation of vital energy stagnation(氣滯血瘀). Remove endogenous heat or fire method(淸瀉火熱法). circulation of phlegm and dampness(運化痰濕). using tonics to cure disease due to deficiency of vital essence of both the liver and the kidney(滋補肝腎) were used for each treatment. 2.The causes of menieres disease were usually mental disturbance due to phlegmatit fire(痰化上搖). dampness-phlegm long standing(痰濕內停), water-dampness retention(水濕停滯), Method of remove heat and circulation phlegm(淸熱化痰法), method of remove water and dampness(利水渗濕法), invigorate function of the spleen and circulation of dampness method(健脾化濕法) were used for each treatment. 3. The causes of toxico-deafness(中毒性 耳聾) were usually heart, liver and kidney functional weakness(心肝腎虛), vital essence and blood weakness(氣血虛弱). Remove obstruction in the flow and circulation phlegm(通窮化痰), reinforce vital energy and tonify blood (補氣活血), using tonics to cure disease due to deficiency of vital essence of both the liver and the kidney(滋補肝腎) were used for each treatment. 4. The causes of deafness (耳聾), tinitus(耳鳴) were usually mental disturbance due to wind and heat(風熱上搖). flaming up of excessive heat of the liver(肝火上亢). exhaustion seat of reproductive essence in kidney(腎精虧虛). Remove endogenous heat and disperse wind(淸熱疏風). remove the fire of liver(淸肝瀉火), through nourish kidney check exuberance of yang(滋腎潛陽), nourish kidney yang(補腎陽). replenish vital energy and improve essential substance(益精血), blood activate for treatment of blood stasis(活血化瘀) were used for each treatment. 5. The effects of mainly used drugs were classified into method of water and dampness remove medicine(利水渗濕藥), nourishing liver and kidney medicine(補肝腎藥), improve blood and vital energy activate medicine(活血行氣藥), through nourish yan medicine check exuberance of yang(滋陰潛陽藥).

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Surface measurements of the 5 June 2013 damaging thunderstorm wind event near Pep, Texas

  • Gunter, W. Scott;Schroeder, John L.;Weiss, Christopher C.;Bruning, Eric C.
    • Wind and Structures
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    • 제24권2호
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    • pp.185-204
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    • 2017
  • High-resolution wind measurements at 2.25 m in height were used to investigate the mean and turbulence properties of an extreme thunderstorm wind event in West Texas. These data were combined with single Doppler scans from the Texas Tech University Ka-band mobile Doppler radars systems (TTUKa) to provide meteorological context over the surface measurement stations for portions of the outflow. Several features characteristic of a severe wind event were noted in the radar data, including a bowing portion of the thunderstorm complex and a small circulation on the leading edge. These features were reflected in the surface wind time histories and provided natural separation between various regions of the outflow. These features also contributed to the peak 1-s gust at all measurement stations. The turbulence characteristics of each outflow region were also investigated and compared. Reduced values of running turbulence intensity and elevated values of longitudinal integral scales were noted during the period of peak wind speed. Larger scales of turbulence within the outflow were also suggested via spectral analysis.

영동과 영남 지역에서 발생한 두 대설의 발달 메커니즘 비교 (Comparison of Development Mechanisms of Two Heavy Snowfall Events Occurred in Yeongnam and Yeongdong Regions of the Korean Peninsula)

  • 박지훈;김경익;허복행
    • 대기
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    • 제19권1호
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    • pp.9-36
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    • 2009
  • Two heavy snowfall events occurred in Yeongnam and Yeongdong regions of the Korean Peninsula during the period from 4 to 6 March 2005 are analyzed. The events were developed by two different meso-scale snow clouds associated with an extratropical low passing over the Western Pacific. Based on synoptic data, GOES-9 satellite images, and precipitation amount data, the events were named as Sokcho and Busan cases, respectively. We analyzed the development mechanism of the events using meterological variables from the NCEP(National Centers for Environmental Prediction) /NCAR(National Centers for Atmospheric Research) reanalysis data such as potential vorticity(PV), divergence, tropopause undulation, static stability, and meridional wind circulation. The present analyses show that in the case of Sokcho, the cyclonic circulation in the lower atmosphere in the strong baroclinic region induced the cyclonic circulation in the upper atmosphere. The cyclonic circulation in the lower and upper atmosphere caused a heavy snowfall in the Sokcho region. In the case of Busan, the strong cyclonic circulation in the upper atmosphere was initiated by the stratospheric air intrusion with the high positive PV into the troposphere during the tropopause folding. The upper strong cyclonic circulation enhanced the cyclonic circulation in the lower disturbed atmosphere due to the extratropical low. This lower cyclonic circulation in turn, intensified the upper cyclonic circulation, that caused a heavy snowfall in the Busan region.

비선형 구속 와류 보정법을 이용한 수평축 풍력 발전기의 공력 해석 (Aerodynamic Analysis of Horizontal Axis Wind Turbines using Nonlinear Bound Vortex Correction Method)

  • 김호건;이승민;이수갑
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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    • pp.307-310
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    • 2008
  • Nonlinear Vortex Strength Correction Method is developed for improvement of vortex lattice method which can't calculate the separated flow conditions and the viscous effect. In this method, the vortex strength on the blade surface is determined by matching the lift force from vortex lattice method with the lift force from aerodynamic coefficients table as the same circulation is added to or subtracted from all chord wise vortices. For considering the nonlinearities due to the neighboring blade sections, sophisticated Newton-Rapson algorithm is applied. The validation of this method was done by comparing the simulations with the measurements on the NREL Phase-VI horizontal axis wind turbine(HAWT) in the NASA Ames wind tunnel under uniform conditions. This method gives good agreements with experiments in most cases.

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지표면 변화와 인공열이 바람장에 미치는 영향에 관한 수치 시뮬레이션 (Numerical Simulation of Effect of Urban Land-use Type and Anthropogenic Heat on Wind Field)

  • 홍정혜;김유근
    • 한국대기환경학회지
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    • 제16권5호
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    • pp.511-520
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    • 2000
  • The urban atmosphere is characterized by th difference in surface and atmospheric environment between urban and more natural area. To investigate th climatic effect of land use type and anthropogenic heat of urban on wind field, numerical simulations were carried out under typical summer synoptic condition. The wind model PNU_MCM(Pusan National University Mesoscale Circulation Model) is based on the three-dimensional Boussinesq equations, taking into account the hydrostatic assumption . Since lane-use differs over every subdivision on Pusan the surface energy budget model includes sub0grid parameterization scheme which can calculate the total heat flux over a grid surface composed of different surfaces. The simulated surface wind agrees well with the observed value, and average over 6 days which represent typical summer lan-sea breeze days, August 1998, i.e. negligible gradient winds and almost clear skies. Urbanization makes sea-breeze enhance at day and reduce land-breeze at night. The results show that contribution of land-use type is much larger than that of anthropogenic heat in Pusan.

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A Numerical Experiment on the Dispersion of the Changjiang River Plume

  • Bang, In-Kweon;Lie, Heung-Jae
    • Journal of the korean society of oceanography
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    • 제34권4호
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    • pp.185-199
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    • 1999
  • With a realistic geography and topography the Princeton Ocean Model is used to study the effects of topography, wind and time-varying Chanajiang (Yangtze) River discharge on the dispersion of the Chanaiiang River plume in the Yellow and East China Seas. The topographic feature of deepening offshore suppresses the offshore expansion of the discharged low salinity water while spreading along the coast is not hindered. Also the spreading of the Chanajiang River plume is very sensitive to wind conditions and the southerly wind is most responsible for the eastward expansion toward the Cheju Island. It is also shown that the influence of the Chanajiang River Diluted Water on the hydrography and circulation of the Yellow Sea including the South Sea of Korea is substantial even in the absence of tide, wind and current.

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Numerical studies on dynamic response of interactive system between atmosphere and ocean

  • Ryu, Chan-Su;Lee, Soon-Hwan
    • 한국환경과학회:학술대회논문집
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    • 한국환경과학회 2003년도 International Symposium on Clean Environment
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    • pp.226-231
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    • 2003
  • A coupling system of MM5 and POM using Stampi with different kinds of parallel computer is proposed and comparative numerical simulations of mesoscale wind induced by topography around East Sea/Sea of Japan are carried out. The results are as follows: 1) Strong horizontal conversion is induced by high mountain Pekdoo at its leeside. 2) The conversion winds at lee of high mountain are not clear in monthly and yearly mean NCEP-reanalysis because of coarse resolution of 1.86 degree by 1.86 degree. But Wind conversion is well simulated at atmosphere and ocean coupling system. And the conversion area of lee side of mountain is also agreed well with observed data of NSCAT launched in satellite ADEOS. 3) The surface ocean current is well correspondent with wind direction, induced by high mountains. And small different wind field information lead the different of particle distribution in numerical experiments of particle distribution on ocean surface.

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