• 제목/요약/키워드: northeasterly

검색결과 43건 처리시간 0.025초

우리나라 근해구역의 계절별 평균 풍향$\cdot$풍속 고찰 (Seasonal Mean Wind Direction and Wind Speed in a Greater Coasting Area)

  • 설동일
    • 해양환경안전학회:학술대회논문집
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    • 해양환경안전학회 2003년도 추계학술발표회
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    • pp.163-166
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    • 2003
  • The seasonal mean wind direction and wind speed in a greater coasting area are investigated using the ECMWF(European Centre for Medium-Range Weather Forecasts) data for 11 years from 1985 to 1995. In winter, the main wind direction in Korea and vicinity, Taiwan and vicinity, and the North Pacific Ocean of middle latitudes is a northwesterly wind, northeasterly wind, and westerly wind respectively. The wind speed is strongest in the East China Sea, the South China Sea, and the North Pacific Ocean of low latitudes(Beaufort wind scale 5-6). A distribution pattern of wind direction in spring and fall is similar to that in winter. Seasonal mean wind speed is strongest in winter and the next is fall. The wind speed in summer is generally weak. However, that in the Indochina and vicinity is strong by the influence of Asian monsoon.

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BORA IN THE ADRIATIC SEA AND BLACK SEA IMAGED BY THE ENVISAT SYNTHETIC APERTURE RADAR

  • Ivanov, Andrei Yu.;Alpers, Werner
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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    • pp.964-968
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    • 2006
  • Bora events over the Adriatic Sea and Black Sea are investigated by using synthetic aperture radar (SAR) images acquired by the Advanced Synthetic Aperture Radar (ASAR) onboard the European Envisat satellite. These images show pronounced elongated patterns of increased sea surface roughness caused by bora winds. The comparison of the SAR images with wind fields derived from Quikscat data confirms that in all cases a strong northeasterly wind was blowing from the mountains onto the sea. It is shown that the SAR images reveal details of the spatial extent of the bora wind fields over the sea which cannot be obtained by other instruments. Furtheremore, also quantitative information on the wind field is extracted from the SAR images by using a wind scatterometer model.

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The Physical Environments and Cochlodinium polykrikoides Bloom in the Sea near Naro-Do

  • Lee, Dong-Kyu;Kang, Yoon-Hyang
    • Ocean and Polar Research
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    • 제25권3호
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    • pp.303-314
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    • 2003
  • The initiation of Cochlodinium polykrikoides blooming in the South Sea of Korea occurs in the sea near Naro-Do in late August. In this paper, the relationships of this annual occurrence with the environmental conditions are presented. In early summer, the winds in the sea near Naro-Do are southwesterly and the upwelling occurs in the near-shore area. The favorable winds to the upwelling are relaxed in August and the downwelling favorable northeasterly winds set in around late August. The change of wind direction causes the onshore transport of warm-and-fresh off-shore water into the sea near Naro-Do and a front between near-shore water and off·shore water is formed. Along the front, downwelling occurs and the environmental conditions for the diatom become unfavorable. When the typhoon and storm bring well-mixed East China Sea water into the sea near Naro-Do in September, the conditions for the dinoflagellates become unfavorable and blooming of C. polykrikoides disappears.

낙동강 수계 중의 댐 건설에 의한 주변의 국지기상환경 변화 -II. 수치모델을 이용한 추정- (A change of local meteorological environment according to dam construction of Nakdong-River -II. Estimation using numerical model-)

  • 전병일;이영미
    • 한국환경과학회지
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    • 제11권4호
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    • pp.281-288
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    • 2002
  • This study was carried out for reading the change of local meteorological environment according to dam construction of Nakdong-river using numerical model. The study used PSU/NCAR Mesoscale Model version5(MM5) for inquiring effect of formation of artificial lake after dam construction. The colleague simulated temperature mixing ratio, latent heat flux and sensible heat flux in two cause of existing lake and not. Temperature and mixing ratio in southwest of Andong lake increased because of the air that was warm and moist above the lake moved to southwest due to the northeasterly wind. In the case of existing lake around Andong, latent heat flux increased much in the daytime after sunrise. However, sensible heat flux decreased but it didn't change distinctly in southwest of Andong like the other values.

GIS와 CFD 모델을 활용한 건설 현장 방풍벽 설치가 비산 먼지 확산에 미치는 영향 연구 (A Study on the Effects of Wind Fence on the Dispersion of the Particles Emitted from the Construction Site Using GIS and a CFD Model)

  • 김동주;왕장운;박수진;김재진
    • 대한원격탐사학회지
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    • 제34권5호
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    • pp.763-775
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    • 2018
  • 본 연구에서는 지리정보시스템(GIS)자료와 전산유체역학(CFD) 모델을 사용하여 방풍벽이 건물 밀집 지역에 위치한 공사 지역에서 발생하는 대기오염물질의 확산에 미치는 영향에 대해 분석하였다. 부산 ASOS에서 10년 동안 관측된 풍속을 평균하여 기준 고도(지상 10 m)에서의 유입류로 사용하였다. 수치 실험은 방풍벽 건설 전과 5 m 및 10 m 높이의 방풍벽을 건설한 후에 대해 16 방위 풍향을 유입류로 진행하였고, 부산 ASOS에서 높은 빈도를 나타낸 북동풍과 남남서풍에 대한 상세 흐름을 분석하였다. 북동풍에서는 북동쪽에서 불어오는 흐름에 의해 비산 먼지가 확산되어 공사 지역 내부에 위치한 감천초등학교에서 대기오염물질 농도가 높게 나타났다. 5 m 높이의 방풍벽을 설치했을 때는 방풍벽 설치 전에 비해 풍속이 조금 감소했고 비산 먼지의 확산이 줄었다. 10 m 높이의 방풍벽을 설치한 경우, 초등학교에서의 평균 대기오염물질 농도는 37% 감소하였다. 남남서풍 유입류에서는 지형과 건물의 영향으로 공사 지역에서 복잡한 흐름 패턴이 형성되었다. 남쪽 공사 지역에서는 비산 먼지가 정체되어 농도가 높게 나타난 반면, 초등학교는 북풍의 흐름에 의해 대기오염물질 농도가 높게 나타났다. 방풍벽 건설 후에는 공사 지역 내부에서 풍속이 감소하면서 공사장 내부 농도는 높아졌지만, 초등학교에서의 농도는 감소했다.

해양기상 관측자료를 이용한 서해 중부해역 해무 분석 (Analysis of a Sea Fog Using Ocean-air Observation Data in the Mid-Yellow Sea off Korea)

  • 오희진;이호만;서태건;윤용훈;김태희
    • 한국지구과학회지
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    • 제24권4호
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    • pp.303-314
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    • 2003
  • 2002년 7월 8일에서 10일까지 AWS와 CTD를 이용하여 서해 중부 연안역에서 해양기상관측을 실시하였다. 수심이 낮은 태안반도 연안역에서 17$^{\circ}C$ 이하의 냉수가 출현하였고, 36$^{\circ}$20'N와 36$^{\circ}$30'N 사이에 정선을 따라 조석전선이 형성되었다. 기온의 분포는 수온의 분포양상과 유사하게 나타났다. 덕적도 주변(Al)에서 24시간 연속관측결과, 조류와 같은 주기로 북동부로부터 고온저염수와 남서부로부터 저온고염수의 이동이 관측되었다. 관측기간 중에 7월 8일 23시에서 9일 1시 30분까지, 9일 3시에서 5시까지 해무가 발생하였다. 해무발생 시 북태평양 고기압이 약해지면서 기온은 18$^{\circ}C$까지 하강하였고, 바람은 2-4m/s의 북동풍이 불었다. 위성사진을 분석하였을 때, 이 안개는 표층수온이 높은 황해서부를 중심으로 발생하여 시간이 지나면서 관측해역으로 확장된 증기안개이다. 이 해무는 기온과 풍속이 상승하면서 소멸되었다.

영일만에서 고주파 레이더로 관측된 수렴(침강)과 수온변동 (High-frequency Radar Observations of Convergence (Downwelling) and Water Temperature Variations in Yeongil Bay)

  • 황보경;손영태;김형록;박지혜
    • 해양환경안전학회지
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    • 제29권1호
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    • pp.1-14
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    • 2023
  • 동해연안의 반폐쇄성 해역인 영일만에서 고주파해양레이더(HF-Radar)로 측정된 표층 해수유동 자료를 활용하여 1)바람과 수평적인 해수유동 사이의 상관성을 파악하고 2)수직적으로 조밀한 간격의 층별 수온시계열 자료와 연계하여 수평적 및 수직적 해수유동의 특성을 파악하였다. 시계열 관측기간 중 영일만 해역의 전역에 걸쳐 북동풍이 우세하게 나타났을 때 표층부터 저층까지 수온의 급격한 상승이 동반되었다. 또한 표층의 장주기 해수유동에서도 풍향과 유사한 방향의 흐름이 뚜렷하게 관측되었다. 바람과 표층 해류 사이의 지연상관 분석을 통해 영일만에 북동풍의 바람이 불기 시작하여 일정하게 지속된다면 짧은 시간(1 ~ 2시간) 내에 남서향의 표층 해류가 발생되는 것을 확인하였다. 일평균된 장주기 표층 해류로부터 수렴과 발산을 계산하였고 이를 통해 층별 관측지점에서 발생한 두 번의 급격한 저층수온 상승이벤트가 모두 영일만의 북동풍과 연관된 표층 해수(상대적 고온수)의 수렴(침강) 현상으로 인해 나타난 것으로 판단하였다.

A Three-Dimensional Numerical Study of Effects of Typhoons on Oceanographic Conditions in the Korea Strait

  • Hong, Chul-Hoon
    • Journal of the korean society of oceanography
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    • 제34권2호
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    • pp.73-85
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    • 1999
  • When typhoons passed around the Korea Strait, some observation in this strait carried out by Mizuno et al. (1986) gives us the following oceanographic features; 1) the direction of the observed current was opposite to the northeasterly wind, 2) temperature rapidly increased having a time lag as the depth deepens, after then decreased with oscillation. A primitive equation ocean model that makes use of a sigma-coordinate system and incorporates a typhoon model was used to examine the mechanism to generate these phenomena. The model region covers the East China Sea, the Yellow Sea, and a portion of the East Sea (Japan Sea). The model well reproduces the observed features, especially in temperature field, and clearly manifests how the above observed features happened. From early time when the typhoon was located in low latitude, an alongshore northward current in the west of Kyushu (hereafter the West Kyushu Current) is generated by an alongshore wind in the typhoon. This current flows into the eastern channel, as a coastal jet, regardless to the wind field within the Korea Strait during this period. The above observed phenomena are generated by this current. The model results indicate that when typhoons pass around the Korea Strait, the West Kyushu Current is generated, and oceanographic condition in the strait should be greatly influenced by this current.

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수치모델을 이용한 홀로세 중기의 아시아 몬순순환 변화 연구 (Numerical Simulation of the Asian Monsoon for the Mid-Holocene Using a Numerical Model)

  • 김성중;이방용;박유민;석봉출
    • Ocean and Polar Research
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    • 제27권3호
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    • pp.289-297
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    • 2005
  • The change in global climate and Asian monsoon patterns during the mid-Holocene, 6000 years before present (6 ka), is simulated by a climate model at spectral truncations of T170 with 18 vertical layers, corresponding to grid-cell sizes of roughly 75km. The present simulation is forced with the observed monthly data of sea surface temperatures, and the specified concentration of atmospheric carbon dioxide, while in the mid-Holocene experiment, orbital parameters such as obliquity, precession, and eccentricity are changed to the 6ka conditions. Under such conditions, the precipitation associated with the summer monsoon is enhanced over a wider zonal band from the Middle East to Southeast Asia, while no significant alteration takes Place in winter. The monsoonal wind also increases over the Arabian Sea, showing the enhanced southwesterly wind during summer and northeasterly wind during winter. Overall, the showing of the Asian monsoon is enhanced during the mid-Holocene, especially in summer, which is consistent with the proxy estimates and other previous model simulations.

수치해석을 이용한 초고층 주거건물에서 외풍영향에 의한 외벽 압력 분포 분석 (A Numerical Analysis on the Outside Pressure Distribution by Outdoor Wind Effect in a High-rise Residential Building)

  • 김치완;양순창;안영철
    • 설비공학논문집
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    • 제23권10호
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    • pp.639-645
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    • 2011
  • The object of this study is to analyze and evaluate outdoor wind pressure effect in a high-rise residential building when seasonal wind blow on coast area. The target building consists of 3 tower buildings over 250m in height. For the evaluation of the outdoor wind effect, CFD simulation was performed. The results of the simulations are as follows : 1) In that case of high-rise building, horizontal stream is more affected than vertical stream. 2) In case of summer season northeasterly wind, building pressure distributions are unstable and surface pressures of outside are effected respectively. 3) In case of winter season westerly wind, building preassure differentiations are not so much because of screening effects of the B, and the C buildings. 4) In case of winter season northwesterly wind, front wind affects on the A building directly because of no obstacles.