• Ocean and Polar Research
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• 제36권2호
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• pp.179-187
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• 2014

Directly searching for undiscovered hydrothermal vent sites is inefficient due to the practical difficulty of comprehensively imaging vent fields. Thus, most searches for hydrothermal vent sites rely on the detection of hydrothermal plumes from water column observation. Detecting and measuring the hydrothermal plumes are the most efficient way to infer the presence and distribution of hydrothermal vents. Both the array of vertical casting and lateral towing are the most common methods to discover hydrothermal plumes. In this study, we compared results of cast and tow-yo operations along the same section of a spreading center with a distance of 20.5 km in the North Fiji Basin for mapping hydrothermal plumes. Operation of CTD tow-yo provides a detailed pattern of plumes which enable us to locate the hydrothermal vents. On the other hand, identification of hydrothermal activity can be determined effectively by CTD cast with additional analysis of geochemical tracers. Reduction in the operating time is another advantage of CTD cast operation, especially for regional-scale survey. Our results show that the combination of CTD cast and tow-yo would improve the efficiency of the hydrothermal plume survey to locate new hydrothermal vent sites.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2017년도 공동학술발표회
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• pp.215-215
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• 2017

• 해양환경안전학회지
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• 제16권3호
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• pp.249-258
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• 2010

1961년부터 2010년 현재까지 현행 국가정선해양관측이 고전적 방법에 의해 수행됨으로써 자동화된 시스템의 형태로 실시간 혹은 준실시간으로 자료를 제공하지 못하게 되는 부분에 대한 개선방향을 살펴보고, 우리나라 운용해양시스템의 실용화를 위하여 국가정선해양관측이 나아가야 할 방향을 제시하였다. 선상에서 관측이 끝난 이후부터 데이터베이스에 자료가 저장되는 시점까지 행해지는 수동화된 작업을 대체하기 위해서는, 수온, 염분뿐만 아니라 다양한 자동측정센서가 부착된 CTD(Conductivity-Temperature-Depth)에 연동된 컴퓨터에서 해양관측자료를 처리하고 실시간으로 품질관리를 수행하며 통신수단에 맞게 자료를 전송할 수 있도록 하는 자동화 소프트웨어의 개발이 필요하다. 관측자료를 실시간의 형태로 전송하기 위해서는 Inmarsat 위성통신장비를 활용한 전송시스템이 타당하고, 준실시간 형태의 전송으로는 CDMA(Code Division Multiple Access) 무선통신방식을 사용하여 연안역에 도달했을 때 수집된 자료들을 묶어서 보내는 방식이 적합하다. 실시간 품질관리 과정을 포함시켜 관측시 발생할 수 있는 여러 가지 원인의 오류를 미연에 방지할 수 있을 것이다.

• 수산해양교육연구
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• 제27권6호
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• pp.1842-1853
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• 2015

The behavior characteristics of the saltwater intrusion in the Seomjin River Estuary by the inflow of fresh water were analysed by the field observation using CTD in the neap tide in January, June, and August 2013 as well as a numerical model, EFDC (Environmental Fluid Dynamics Code). As a result, Seomjin River Estuary is found that the saltwater intrusion is sensitive to the tide and tidal and freshwater flow. The results of field observation and numerical model were similar in the range of salt, but the results of salt wedge distribution were quite different. The observation of tide and tidal current as well as hydrographic surveying the Seomjin River Estuary will be jointly conducted for the accurate analysis.

• 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.

• Ocean and Polar Research
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• 제37권2호
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• pp.107-117
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• 2015

Thorpe scale analysis was performed using two sets of 25-hour-long hourly CTD data. Raw density profiles collected on the continental slope of the southwestern East Sea were post-processed to reduce instrument noises and measurement errors. Density inversions were detected by applying the overturn ratio test proposed by Gargett and Garner (2008). The value of $K_z$ below the main thermocline estimated with the Osborn parameterization was $5.3{\times}10^{-4}(1.1{\times}10^{-4})m^2s^{-1}$ and that with the Shih parameterization was $5.9{\times}10^{-5}(2.4{\times}10^{-5})m^2s^{-1}$during the spring (neap) tidal period. This result suggests that internal tides can enhance vertical mixing in the observation region.

• 한국해양학회지:바다
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• 제16권4호
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• pp.206-211
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• 2011

수영만의 CTD 관측자료와 모니터링 부이의 바람, 수온, 유속자료를 이용하여 해운대 냉수대의 변동과 원인을 연구하였다. 해류는 단주기 변동이 크고 바람과는 관련이 없었다. 해안에 평행한 북동-남서 방향의 바람은 전체 분산의 96% 이상을 차지하며 수온변화의 주된 요인이었다. 수온은 풍향에 민감하여 남서풍으로 바뀌면 바로 수온이 감소하기 시작하고 반대로 북동풍으로 바뀌면 상승하였는데, 남서풍이 2일 동안만 불어도 수온이 감소하는 경우가 세 번이나 되었다. 전체적으로 2009년에는 8월부터 5일 이하의 비교적 짧은 용승이 네 번, 그리고 2010년에는 총 7차례 중에서 7일간의 용승 3번과 18일간의 용승이 l회 기록되었다. 이 중에서 2010년 8월 중순에 발생한 용승은 7일 동안 수온이 $10^{\circ}C$ 이상 감소하여 바람에 비해 매우 강력한 용승 효과를 보였다. 감포, 울산, 기장에서도 냉수대 기간에 해운대와 같은 경향으로 수온이 감소하였고 CTD 관측과 인공위성의 수온분포 또한 연안용승 해역이 해운대-부산까지 확장될 수 있음을 보여주었다. Wavelet coherence 분석에 의하면 2~8일 주기의 성분이 용승이 잦은 기간에 상관성이 높았다.

• 한국해양공학회지
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• 제16권1호
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• pp.16-22
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• 2002

The diffusion characteristics of an ocean dumping material in the south-eastern East/Japan Sea related to regulate the physical characteristics with the observation and the hydraulic experiment are investigated. The main results are as follows; (1) Spying CTD observation result of the area of Jung in the East/Japan Sea, the ocean dumping area had influenced the Tsushima Warm Current of high temperature and salinity. Horizontal turbulent diffusivity is 1.913$\times$10$^{7}$ by drogue tracking. (2) From the experiment of settling, the initial settling velocity of each material is 1.0~2.7 cm/sec according to the specific gravity and initial concentration. In the pycnocline, particles didn't settle under the pycnocline any more and accumulated. It is signified that calculation of the sedimentation rate of the ocean dumping material including of vertical diffusion must be regard the pynocline in the ocean area have well-developed pycnocline. (3) Vertical turbulent diffusivity were 2.219$\times$10$^{-8}$ ~8.874$\times$10$^{-4}$ cm$^2$/sec from the experiment of settling. And, the pycnocline influenced the vertical turbulent diffusivity.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.553-556
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• 2004

Spatial and temporal aspects of toxic dinoflagellate Cochlodinium.p blooms and consequences of physical features in complex coastal ecosystems, off the southern Korean coast, have been investigated using data obtained from SeaWiFS and AVHRR as well as in-situ observations. Hydrographic parameters measured using CTD sensors were used to elucidate physical factors affecting the spatial distribution and abundance of Cochlodinium.p blooms. The results show spatial and temporal variations of chlorophyll-a (Chl-a) and sea surface temperature (SST) and reveal significant information about Cochlodinium.p blooms and process underlying their evolution. Satellitederived Chl-a estimates appear to be potential in explicating the evolution, movement and distribution of Cochlodinium.p blooms in the enclosed bays of the South Sea. The existence of thromohaline waters offshore provide favorable conditions for the rapid growth and subsequent southward initiation of Cochlodinium.p blooms that are influenced to flow on the offshore branch (OB) during September. It was observed that there was a significant variation in the sun-induced chlorophyll-a fluorescence signal in the remote sensing fluorescence spectra and its high-intensity was recognized during the period of exponential growth and physical transport. Satellite-derived Chl-a concentration during September 1999 ranged between $3­60mg/m^3$ inside the Jin-hae and adjacent Bays and $1-6mg/m^3$ in offshore waters, with varying Cochlodinium.p abundances 1500 to 26000 cells $ml^{-1}.$ The closely spaced CTD surveys and satellite-derived SST give a complete overview on the initiation of Cochlodinium.p blooms in hydrodynamically active regions of the offshore southern East Sea by the influence of Tsushima Warm Current (TWC).

• Ocean and Polar Research
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• 제28권3호
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• pp.339-352
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• 2006

Seasonal and tidal variations of density stratification in the Saemangeum waters are investigated based on synoptic CTD observations between July 2003 and September 2005. CTD data used in this study are those obtained after closing the dike No. 4 and before closing the two final gaps, the Sinsi and the Garyeok, on the Saemangeum tidal harrier. A total of 19 field campaigns comprehend a wide temporal spectrum, that is, few seasons, spring and neap tides, and high and low waters. In addition, ADCPs were anchored and CTDs were cast at three stations for 25 h in July 2005. Water columns are vertically homogeneous in autumn and winter. The vertical homogeneity persists in spring but with an occasional weak stratification in i:he northern part of the Gogunsan Islands. Increased reshwater runoff tends to stabilize the water columns and strong density stratification is established in summer. The mean potential energy anomaly (PEA) in summer used as a stratification parameter is the largest $(27.7\;J\;m^{-3})$ in the northern part of the Gogunsan Islands where the Geum River discharge dominates, the smallest $(16.9\;J\;m^{-3})$ is in the inner area of the barrier, in between the two $(21.6\;J\;m^{-3})$ in the southern part of the Gogunsan Islands. Whereas the stratification is generally strengthened in summer, strong winds or large tidal currents over the shallow depths frequently destratify the water column near the mouth of river runoff inside the tidal barrier. Periodic stratification, the development of stratification on the ebb and its breakdown on the flood, occurs in the mid-area inside the barrier induced by the tidal straining, which can also be found in the results of 25 h observation.