• Title/Summary/Keyword: Wind circulation

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

  • Lee, Jae-Chul;Kim, Jeong-Chang
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.12 no.3
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    • pp.219-224
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    • 2007
  • Two monitoring buoys equipped with ADCP were deployed at the deepest positions along the trough of the central Gwangyang Bay in spring 2006 in order to study the circulation in the bay. Northward velocity is commonly dominant at both stations located in the eastern part of the channel, which supports the cyclonic circulation accompanied by the southward flow in the western part. The southern station has a distinct two-layer structure with current reversal at 14 m depth and increasing northward velocity in the lower layer to 36 m depth close to the bottom. At the northern station the northward flow becomes accelerated due to the decrease in the cross-sectional area and this northward current is dominant even in the upper layer. In the modal structure from the EOF analysis, the first mode has 74% of total variance at the northern station whereas it is 67% but the baroclinic portion increases at the southern station. The typical northward velocity is about 10 cm/s which is associated with the cyclonic circulation. Subtidal variability due to the local wind effect is negligible, but the nonlocal response associated with offshore Ekman flux by the zonal wind is found during strong wind events.

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

  • Byon, Jae-Young;Choi, Young-Jean;Seo, Beom-Keun
    • Journal of the Korean earth science society
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    • v.30 no.4
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    • pp.464-477
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    • 2009
  • In this study, we examined the patterns of local circulation over the Daechung lake area through the numerical experiment designed to investigate the impact of lake on the local circulation. The results of numerical experiment showed that the surface temperature predicted by WRF model was lower than the observation, while the wind speed was stronger than the observation. The local circulation over the lake area was characterized by a lake breeze induced by a horizontal thermal contrast between the lake surface and the Surrounding land. At Daecheong Lake, a lake breeze formed at 09 LST and dissipated at 18 LST, with maximum intensity at 15 LST. The vertical extent of the simulated circulation was about 1,200 m. The specific humidity increased as the humid air above the lake moved landward due to the daytime circulation of the lake breeze. The numerical experiments of sensitivity to existence of the lake showed that the simulated surface temperature decreased in the experiment with the lake. Wind speed was more intense around the lake area when the actual land use was substituted by grassland land use. The results of numerical experiments suggest that the lake-induced lake breeze circulation has an effect on the meteorology of planetary boundary layer around the lake.

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

  • Yoon, Han-Sam;Lee, In-Cheol
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.8 no.3
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    • pp.140-147
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    • 2005
  • We investigated the interactions between coastal waters of the Yeongil Bay, Korea, and oceanic waters of the Eastern Sea, as wet 1 as the development mechanism of vertical circulation currents in the bay. The oceanic waters of the bay have an average water temperature of $12.2{\sim}18.4^{\circ}C$ and salinity of $33.32{\sim}34.43$ PSU. Results of spectral analysis have shown that the period of revolution between oceanic and coastal waters is about 0.84-0.91 years in the surface waters and 1.84 years in the bottom layer. The wind direction in the bay shifts between SW and NE, with the main wind direction being SW during the winter period, and water mass movement is influenced by such seasonal variations in wind direction. Vertical circulation currents in the bay are structured by two phenomena: the surface riverine outflow layer from the Hyeong-san River into the open sea and the bottom oceanic inflow layer with high-temperature and salinity into the bay. These phenomena start the spring when the water mass is stable and become stronger in the summer when the surface cold water develops over a 10-day period. Consequently, tidal currents have little influence in the bay; rather, these vertical and horizontal circulation currents play an important role in the transport of the pollutant load from the inner bay to the open sea.

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

  • Kim, Seong-Bae;Kim, Jong-Han;Lim, Gyu-Sang
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.7 no.1
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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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    • v.24 no.2
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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.

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

  • Park, Ji-Hun;Kim, Kyung-Eak;Heo, Bok-Haeng
    • Atmosphere
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    • v.19 no.1
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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.

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

  • Kim, Ho-Geon;Lee, Seung-Min;Lee, Soo-Gab
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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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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Numerical Simulation of Effect of Urban Land-use Type and Anthropogenic Heat on Wind Field (지표면 변화와 인공열이 바람장에 미치는 영향에 관한 수치 시뮬레이션)

  • 홍정혜;김유근
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.5
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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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    • v.34 no.4
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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
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2003.11a
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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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