• 제목/요약/키워드: Sea-water level change

검색결과 169건 처리시간 0.025초

수위변동에 따른 갯벌의 물리적 환경특성의 변화 (Variation of Physical Characteristic of Tidal Flat's Environment by Water Level Change)

  • 박종화
    • 한국환경복원기술학회지
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    • 제2권3호
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    • pp.1-9
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    • 1999
  • This paper described the results of the characteristics of the near-bottom flow and field analysis of the tidal flats sediment. It was the aim of this paper to grasp current flow of tidal flat's environment and influence factor for environmental change forecast of tidal flats. Field measurement of water velocity, water elevation, bed materials test, and temperature distribution of tidal flat were conducted. Thereafter, current flow, turbidity and temperature distribution of tidal flat sediment have been discussed. The field research results showed that the fluctuating velocity near the seabed before and after its appearance at low tide was strongly affected by the wind wave. The resuspension of the sea-bottom sediment took place with great intensity before and after the appearance of the seabed at low tide. Both the sea water level and the weather condition were a significant influential factors. Such as, temperature and turbidity just on the surface and the shallow layer of seabed sediments were varied largely with time and weather conditions, but that its deeper layers was almost constant. Temperature on the seabed sediments was strongly influenced by irradiance and water depth. The temperature variation of the tidal flat and the variation characteristics of the current flow and turbidity depend greatly on the inhabiting environment of the tidal flat benthic organism.

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3D Numerical Modelling of Water Flow and Salinity Intrusion in the Vietnamese Mekong Delta

  • Lee, Taeyoon;Nguyen, Van Thinh
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2021년도 학술발표회
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    • pp.207-207
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    • 2021
  • The Vietnamese Mekong Delta(VMD) covers an area of 62,250 km2 in the lowest basin of the Mekong Delta where more than half of the country's total rice production takes place. In 2016, an estimated 1.29 million tonnes of Vietnam's rice were lost to the country's biggest drought in 90 year and particularly in VMD, at least 221,000 hectares of rice paddies were hit by the drought and related saltwater intrusion from the South China Sea. In this study, 3D numerical simulations using Delft3D hydrodynamic models with calibration and validation process were performed to examine flow characteristics, climate change scenarios, water level changes, and salinity concentrations in the nine major estuaries and coastal zones of VMD during the 21st century. The river flows and their interactions with ocean currents were modeled by Delft3D and since the water levels and saltwater intrusion in the area are sensitive to the climate conditions and upstream dam operations, the hydrodynamic models considered discharges from the dams and climate data provided by the Coupled Model Intercomparison Project Phase 6(CMIP6). The models were calibrated and verified using observational water levels, salinity distribution, and climate change data and scenarios. The results agreed well with the observed data during calibration and validation periods. The calibrated models will be used to make predictions about the future salinity intrusion events, focusing on the impacts of sea level rise due to global warming and weather elements.

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Changes in MCSST and Chlorophyll-a Off Sanriku Area (38-43N, 141-l50N) from NOAA/AVHRR and SeaWiFS Data

  • Kim, Myoung-Sun;Asanuma, Ichio
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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    • pp.95-100
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    • 1998
  • The purpose of this study is to describe the change of the spring bloom and oceanographic condition. The variation of pigment concentration derived from the satellite ocean color data has been analyzed. According to the movement of blooming area, blooming was very concerned with a rising trend of sea surface temperature and a supply of nutrients. A nutrient rich water carried by the Oyashio encounters with the warm Core ring, where mixings and blooms are observed. We examined the correlation by using the satellite observations of the temperature and chlorophyll-a for the spring seasons (May, June, July) of 1998 the off Sanriku area (38-43N, 141- l50E). Using the SeaWiFS data, we process the data into the level-3, which contains the geophysical value of chlorophyll-a. And chlorophyll-a data is mapped for the water between 110E and 160E, and 15N and 52N with a 0.08 * 0.05 degree grid for each image. And Sea Surface Temperature (SST) data is produced using the AVHRR onboard the NOAA. The SST is derived by the MCSST. Then, the data is mapped for the water as much as chi-a data. And these gridded image was made by detection of each water masses, which are Kuroshio Extension, the warm-core ring and the Oyashlo Intrusion, etc., using those satellite images to determine short term change. Off Sanriku is a place where warm-water pool and the Oyashio at-e mixed. When warm streamer has intruded in cold water, the volume of phytoplankton increases at the tip of warm streamer. Warm water streamer was trigger of occurring blooming. And also, SeaWiFS images provided as much information for the studies of chlorophyll-a concentrations in the surface.

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지구 온난화에 따른 해양환경 변화와 대책 (Global Wanning Effect on Marine Environments and Measure Practices against Global Wanning)

  • 김도희
    • 해양환경안전학회지
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    • 제16권4호
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    • pp.421-425
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    • 2010
  • 최근 지구온난화로 인한 수온상승과 해수면의 상승으로 인해 해양 생태계가 변화되고 있다고 보고되고 있다. 한반도 주변 해역에서도 수온과 해수면이 상승하고 플랑크톤의 종 조성이 변화되고 가시파래, 불가사리, 해파리 등의 유해 생물종의 출현 빈도가 증가되고 있고, 바다 사막화가 증가되는 등 해양 생태계의 변화로 어업활동이 어려워지고 어업생산량이 감소하여 어민 경제가 심각한 영향을 받고 있다. 본 보고서에서는 지구 온난화의 원인과 그 메커니즘을 소개하고, 지구 온난화에 따른 해양환경 변화와 해양 생태계에 미치는 영향과 그 대책에 관하여 보고하고자 하였다.

영산강 하구둑 및 영암-금호방조제의 방류에 의한 목포항 주변수역의 유동변화 및 선박운용에 미치는 영향에 관한 연구 (A Study on the Change of Current in the Vicinity of Mokpo Harbor and Its Impact on Ship Operation due to the Discharge through Yongsan River Estuary Weir and Yongam-Kumho Sea Dike)

  • 정대득;이중우;국승기
    • 한국항만학회지
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    • 제13권1호
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    • pp.133-146
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    • 1999
  • Mokpo coastal area is connected to the adjacent a long river and two large basins. It is essential for port planning coastal zone management and environmental impact study to analyze the data related to the ship operation and variation of current and water quality due to the development of water area including dredging reclamation and estuary barrage. The Yongsan river estuary weir and Yongam-Kumho basins discharge much of water through water gates for the purpose of flood control and prohibit salt intrusion at the inland fresh water area. To meet this purpose discharge through the gates have been done at the period of maximum water level difference between inner river and sea level. This discharged water may cause the changes of current pattern and other environmental influences in the vicinity and inner area of semi-closed Mokpo harbor. In this study ADI method is applied to the governing equation for the analysis of the changes on current pattern due to discharged water. As the results of this study it is known that the discharging operation causes many changes including the increase of current velocity at the front water area at piers approaching passage and anchorages. Discussion made on the point of problems such as restricted maneuverability and the safety of morred vessels at pier and anchorage. To minimize this influence the linked gate operation discharging warning system and laternative mooring system are recommended.

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위성자료(NOAA, Topex/Poseidon)를 이용한 한반도 주변해역의 기후적 특성 (On Climatic Characteristics in the East Asian Seas by satellite data(NOAA, Topex/Poseidon))

  • 윤홍주
    • 한국환경과학회지
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    • 제10권6호
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    • pp.423-429
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    • 2001
  • Satellite data, with sea surface temperature(557) by NOAA and sea level(SL) by Topex/poseidon, are used to estimate characteristics on the variations and correlations of 557 and SL in the East Asian Seas from January 1993 through May 1998. We found that there are two climatic characteristics in the East Asian seas the oceanic climate, the eastern sea of Japan, and the continental climate, the eastern sea of China, respectively. In the oceanic climate, the variations of SL have the high values in the main current of Kuroshio and the variations of 557 have not the remarkable seasonal variations because of the continuos compensation of warm current by Kuroshio. In the continental climate, SL has high variations in the estuaries(the Yellow River, the Yangtze River) with the mixing the fresh water and the saline water in the coasts of continent and 557 has highly the seasonal variations due to the climatic effect of continents. In the steric variations of summer, the eastern sea of Japan, the East China Sea and the western sod of Korea is increased the sea level about 10~20cm. But the Bohai bay in China have relatively the high values about 20~30cm due to the continental climate. generally the trends of SST and SL increased during all periods. That is say, the slopes of 557 and SL Is presented 0.29$^{\circ}C$/year and 0.84cm/year, respectively. The annual and semi-annual amplitudes have a remarkable variations in the western sea of Korea and the eastern sea of Japan. In the case of the annual peaks, there appeared mainly In the western sea of Korea and the eastern sea of .Japan because of the remarkable variations of SL associated with Kuroshio. But in the case of the semi-annual peaks, there appeared in the eastern sea of Japan by the influence of current, and in the western sea of Korea by the influence of seasonal temperature, respectively. From our results, it should be believed that 557 and SL gradually Increase in the East Asian seas concerning to the global warming. So that, it should be requested In the international co-operation against In the change of the abnormal climate.

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관측자료에 기반한 미래 해수위 예측 및 연안지역 침수위험면적 분석 - 부산시 해운대구 일대를 대상으로 - (Estimation of Peak Water Level Based on Observed Records and Assessment of Inundation in Coastal Area - A Case Study in Haeundae, Busan City -)

  • 안새결;이동근
    • 환경영향평가
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    • 제26권6호
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    • pp.445-456
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    • 2017
  • 해수면상승으로 인한 연안지역의 영향평가를 위해 부산시 해운대구 일대를 대상으로 해수위 예측모형과 미래 침수위험지역 분석을 수행하였다. 과거 평균해수위자료(1960-2016)를 활용한 통계적 분석을 통해 해수면상승 예측 모형과 불규칙 성분을 산정하고 파고자료(2012-2017)와 계산 조위값의 확률밀도함수와 종합하여 몬테카를로 시뮬레이션을 통해 해수면상승, 불규칙 성분, 파고, 조위를 종합한 미래 최고해수위를 모의하였다. 이에 미래 1% 발생가능성 최고해수위는 2050, 2080, 2100년 2.3, 2.6, 2.8m로 나타났으며, 침수위험지역은 우동, 용호동, 송정동, 재송동이 가장 클 것으로 나타났다.

Potential Influence of Climate Change on Shellfish Aquaculture System in the Temperate Region

  • Jo, Qtae;Hur, Young Baek;Cho, Kee Chae;Jeon, Chang Young;Lee, Deok Chan
    • 한국패류학회지
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    • 제28권3호
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    • pp.277-291
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    • 2012
  • Aquaculture is challenged by a number of constraints with future efforts towards sustainable production. Global climate change has a potential damage to the sustainability by changing environmental surroundings unfavorably. The damaging parameters identified are water temperature, sea level, surface physical energy, precipitation, solar radiation, ocean acidification, and so on. Of them, temperature, mostly temperature elevation, occupies significant concern among marine ecologists and aquaculturists. Ocean acidification particularly draws shellfish aquaculturists' attention as it alters the marine chemistry, shifting the equilibrium towards more dissolved CO2 and hydrogen ions ($H^+$) and thus influencing signaling pathways on shell formation, immune system, and other biological processes. Temperature elevation by climate change is of double-sidedness: it can be an opportunistic parameter besides being a generally known damaging parameter in aquaculture. It can provide better environments for faster and longer growth for aquaculture species. It is also somehow advantageous for alleviation of aquaculture expansion pressure in a given location by opening a gate for new species and aquaculture zone expansion northward in the northern hemisphere, otherwise unavailable due to temperature limit. But in the science of climate change, the ways of influence on aquaculture are complex and ambiguous, and hence are still hard to identify and quantify. At the same time considerable parts of our knowledge on climate change effects on aquaculture are from the estimates from data of fisheries and agriculture. The consequences may be different from what they really are, particularly in the temperature region. In reality, bivalves and tunicates hung or caged in the longline system are often exposed to temperatures higher than those they encounter in nature, locally driving the farmed shellfish into an upper tolerable temperature extreme. We review recent climate change and following environment changes which can be factors or potential factors affecting shellfish aquaculture production in the temperate region.

한국 남동해역의 냉수대 발생 변화와 Cochlodinium polykrikoides 적조와의 상관성 연구 (Study on the Correlation Between the Upwelling Cold Waters and Cochlodinium polykrikoides Red Tide in the Southeast Sea of Korea)

  • 김범규;황도현;박수호;김흥민;엥흐자리갈 운자야;김대현;윤홍주
    • 한국전자통신학회논문지
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    • 제14권3호
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    • pp.559-572
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    • 2019
  • 한반도 동해 남부해역은 매년 하계에 집중적으로 냉수대가 형성되어 빈번한 이상해황이 발생한다. 동해안에 발생하는 냉수대는 바람의 영항을 지배적으로 받는데 남풍계열의 바람이 3일에서 7일 이상 지속적으로 불어오는 경우 발생한다. 본 연구에서는 냉수대의 발생과 변화 및 Cochlodinium polykrikoides 적조와의 상관성을 분석하기 위하여 기상청, 한국수력원자력, 해양조사원의 부이의 수온과 풍향 및 풍속, COMS/GOCI의 클로로필 자료, 바람자료와 NOAA에서 제공하는 GHRSST Level 4 SST, 국립수산과학원의 적조속보자료를 활용하였다. 동해안 연안용승시 용승된 수괴는 해류를 따라 북쪽으로 이동하는 특성을 보이며 수괴를 따라 고농도의 클로로필이 형성되는 특성을 보였다. 남쪽의 동한난류의 세력이 강하게 형성될 때 적조가 북상하는 특성을 나타내었다.