• 수산해양기술연구
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• 제33권2호
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• pp.132-140
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• 1997

The basic experiment on the telemetry system of temperature and salinity, which is a study for the effective management of costal fishing-ground nowadays, was carried of 8 days from April 5, 6, 26, 27 , 1996 to May 31 and June 1, 21, 22, 1996 at the fish farm of Yooksam at Samyang-Myun, tongyongkun(34。45.02'N, 128。24.79'E). The results obtained were as follows : 1. The average temperature and salinity of STD of telemetry system was coincided with that of ICTD system calibration precisely. 2. A daily variation of temperature in fish cage which was measured by the telemetry system was influenced mainly by sunrise and sunset. 3. A daily variation of salinity in fish cage which was measured by the telemetry system was influenced mainly by tidal current. 4. The fish school in fish cage was distributed mainly 2~7 m layer during daylight and was arisen to the surface at sunset, was settled down to the bottom at sunrise.

• 수산해양기술연구
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• 제34권2호
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• pp.159-164
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• 1998

In order to investigate the relation between the environmental factors influencing on the fluctuation of fishing condition and the catch of anchovy in gill nets in the coastal waters of Yosu, five oceanographic factors, i.e., water temperature, salinity, chlorophyll-a and the catch of anchovy in gill nets are observed from June 6 to August 12 in 1993. The results obtained are summerized as follows: 1) The water temperature ranged from 16.$0^{\circ}C$ to 22.6$^{\circ}C$ and the salinity from 30.13$\textperthousand$ to 33.65$\textperthousand$. the water temperature and salinity showed no significant influence on the catch of anchovy, but the catch did not expose high values in low temperature and salinity. 2) The catch of anchovy increased with the amount of chlorophyll-a. It is therefore emphasized that the amount of chlorophyll-a is the greatest one of environmental factors influencing on the catch of anchovy.

• 한국해양학회지
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• 제27권4호
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• pp.290-302
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• 1992

기후학적인 관측자료와 담수 효과를 고려한 수치실험에서 얻어진 두가지의 계절별 염분 분포를 열대 대서양 500 m 상층부에 대하여 조사하였다. 해표면 염분의 계절 변 화는 담수의 초과를 가져오는 열대수렴대(ITCZ)의 이동 및 강물 방출 시기에 밀접한 관계가 있었다. 본 연구에서 얻어진 계절별 염분 분포는 Defant (1981)와 Levitus (1982) 등의 이미 존재하는 기후 자료와 대체로 비슷하나, 본 연구의 자료가 온도 분 포에 더 잘 일치하였다. 밀도에 대한 온도 효과와 비교할 때 염분 효과는 100 m 이심 에서는 무시할 만하나 혼합층에서 염분 효과는 상당히 중요하였다. 관측된 염분 분포 와 모델에서 계산된 염분 분포사이에 뚜렷한 차이가 염분값의 위도에 따른 기울기에서 나타났다. 모델에서 유도된 염분은 관측값보다 적도부근의 해양에서 대체로 높게 나타 났으나, 아열대 해역에서는 낮게 나타났다. 남동 대서양 해역과 같은 관측자료가 매우 적은 곳에서 염분 차이는 크게 나타났고, 이런 해역에서 정교한 모델값이 좀 더 정확 한 듯 보인다. 또한 관측값과 모델에서 얻어진 값과의 불일치에 대한 가능한 원인들도 분석하였다.

• 한국지구과학회지
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• 제26권2호
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• pp.129-136
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• 2005

Continued observation of ARGO floats for years(about 4 years) makes the conductivity sensor more vulnerable to fouling by marine life and associated drift in salinity measurements. In this paper, we address this issue by making use of floats deployed in different years. Floats deployed in the East Sea and the Indian Ocean are examined to find out float-to-float match-ups in such a way that an older float pops up simultaneously with a newer deployment (with tolerable space-time difference). A time difference of less than five days and space difference of less than 100km are considered for the match-up data sets. For analysis of the salinity drift under the stable water mass, observations of the floats from deepest water masses have been used. From the cross-check of ARGO floats in the East Sea and the Indian Ocean, it is found that there is a systematic drift in the older float compared to later deployments. All drift results, consistently show negative bias indicating the typical nature of drift from fouled sensors. However, the drift is much less than 0.01, the specified accuracy of ARGO program.

• Ocean and Polar Research
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• 제26권1호
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• pp.33-42
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• 2004

Effect of freshwater discharge on the long-term salt balance in the Northern and Central Indian River Lagoon (IRL) is successfully simulated by a new analytical solution to a water balance-based one-dimensional salt conservation equation. Sensitivity tests show that the salinity levels drop abruptly even during the dry season (November to May) due to the high surface runoff discharge caused by tropical storms, depressions, and passage of cold fronts. Increasing surface runoff and direct precipitation has risen by ten times, lowering the salinity level down to 12psu in the Northern Central zone, and to 17 psu in the Northern zone. However, the salinity level in the Southern Central zone has decreased to 25 psu. High sensitivity of the Northern Central zone to freshwater discharge can be partially explained by a rapid urbanization in this zone. During the dry season, less sensitivity of the Southern Central zone to the increased surface runoff is attributed to the proximity of the zone to the Sebastian Inlet and a strong diffusion condition possibly resulting from the seawater intrusion to the surficial aquifer at the Vero Beach. During the wet season, however, the whole study area is highly sensitive to freshwater discharge due to the weak diffusion conditions. High sensitivity of the IRL to the given diffusion conditions guarantees that the fresh-water release occurs during strong wind conditions, achieving both flood control in the drainage basin and a proper salinity regime in the IRL.

• 대한원격탐사학회지
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• 제26권1호
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• pp.59-64
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• 2010

유럽 우주국 (ESA)에서 지구 탐사 계획의 일환으로 개발한 두 번째 위성인 SMOS (Soil Moisture and Ocean Salinity) 위성이 지난 2009년 11월 발사되어 궤도에 안착, 운행 중에 있다. SMOS는 탑재된 L 대역 합성 개구형 라디오미터를 이용하여 상시 전지구적으로 토양 수분량과 해양 염도를 측정하는 것을 목표로 한다. 이를 통하여 지구의 물순환 및 기상, 기후 연구에 주요한 데이터를 얻을 수 있다. 본 글은 SMOS 발사와 관련된 개괄적인 연구 개발과 현재 운용 현황에 대해 설명한다.

• Ocean and Polar Research
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• 제38권4호
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• pp.259-270
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• 2016

Sea Surface Salinity (SSS) observations from the Aquarius satellite in the East Sea show large systematic biases mainly caused by the surrounding lands and Radio Frequency Interferences (RFI) along the descending orbits on which the satellite travels from the Asian continent to the East Sea. To develop a technique for correcting the systematic biases unique to the East Sea, the least square regression between in situ observations of salinity and the reanalyzed salinities by HYCOM is first performed. Then monthly mean reanalyzed salinities fitted to the in situ salinities are compared with monthly mean Aquarius salinities to calculate mean biases in $1^{\circ}{\times}1^{\circ}$ boxes. Mean biases in winter (December-March) are found to be considerably larger than those in other seasons possibly caused by the inadequate correction of surface roughness in the sea surrounded by the land, and thus the mean bias corrections are performed using two bias tables. Large negative biases are found in the area near the coast of Japan and in the areas with islands. In the northern East Sea, data sets using the ascending orbit only (SCIA) are chosen for correction because of large RFI errors on the descending orbit (SCID). Resulting mean biases between the reanalysis salinities fitted to in situ observations and the bias corrected Aquarius salinities are less than 0.2 psu in all areas. The corrected mean salinity distributions in March and September demonstrate marked improvements when compared with mean salinities from the World Ocean Atlas (WOA [2005-2012]). In September, salinity distributions based on the corrected Aquarius and on the WOA (2005-2012) show similar distributions of Changjiang Diluted Water (CDW) in the East Sea.

• Ocean and Polar Research
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• 제29권1호
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• pp.33-42
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• 2007

To obtain the overall distribution patterns and characteristics of the East Sea Intermediate Water (ESIW), the historical data obtained by the Japan Maizuru Marine Observatory (MMO) and the Korea Ocean Research and Development Institute (KORDI) were analyzed. To obtain water characteristics of the ESIW on isopycnal surfaces, temperature, salinity and dissolved oxygen were interpolated at every 0.01 interval of potential density. And then the interpolated values were averaged at the same potential density. This potential density average method preserved the salinity minimum layer more clearly compared to the depth average method. The potential density(${\sigma}_{\theta}$) range of the ESIW was $26.9{\sim}27.3$. The representative potential density of the ESIW was found to be 27.2, because the characteristics of the ESIW was clear at this density. From the horizontal distributions of physical properties on the isopycnal surface of $27.2{\sigma}_{\theta}$ it is suggested that the low salinity ESIW circulates anticlockwise over the whole basin with the high salinity intermediate water. The low salinity intermediate water extended from the northwestern part to the east along the sub-polar front and to the Ulleung Basin along the east coast of Korea.

• Ocean and Polar Research
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• 제43권4호
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• pp.321-334
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• 2021

'Marine mammals-based observations' refers to data acquisition activities from marine mammals by instrumenting CTD (Conductivity-Temperature-Depth) sensors on them for recording vertical profiles of ocean variables such as temperature and salinity during animal diving. It is a novel data collecting platform that significantly improves our abilities in observing extreme environments such as the Southern Ocean with low cost compared to the other conventional methods. Furthermore, the system continues to create valuable information until sensors are detached, expanding data coverage in both space and time. Owing to these practical advantages, the marine mammals-based observations become popular to investigate ocean circulation changes in the Southern Ocean. Although these merits may bring us more opportunities to understand ocean changes, the data should be carefully qualified before we interpret it incorporating shipboard/autonomous vehicles/moored CTD data. In particular, we need to pay more attention to salinity correction due to the usage of an unpumped-CTD sensor tagged on marine mammals. In this article, we introduce quality control methods for the marine mammals-based CTD profiles that have been developed in recent studies. In addition, we discuss strategies of quality control specifically for the seal-tagging CTD profiles, successfully having been obtained near Terra Nova Bay, Ross Sea, Antarctica since February 2021. It is the Korea Polar Research Institute's research initiative of animal-borne instruments monitoring in the region. We anticipate that this initiative would facilitate collaborative efforts among Polar physical oceanographers and even marine mammal behavior researchers to understand better rapid changes in marine environments in the warming world.

• Ocean and Polar Research
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• 제26권2호
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• pp.299-309
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• 2004

Conductivity-temperature-depth (CTD) data obtained along a meridional section in the eastern tropical Pacific in July 2003 have been analyzed to identify various water masses, and to examine the hydrographic structure and zonal geostrophic currents in the upper 1000 m. Water mass analysis shows the existence of subtropical and intermediate waters, characterized by layers of subsurface salinity maximum and minimum, originating from both hemispheres of the Pacific. Vertical section of temperature in the upper 200 m shows the typical trough-ridge structure associated with the zonal current system for most of the tropical Pacific. Water with the lowest salinity of less than 33.6 was found in the upper 30 m between $8.5^{\circ}N$ and $10.5^{\circ}N$ in a boundary zone between the North Equatorial Current and North Equatorial Countercurrent. Temporal changes in water properties observed at $10.5^{\circ}N$ over a period of 9 days suggest both the local rainfall and horizontal advection is responsible for the presence of the low-salinity water. Development of a barrier layer was also observed at $10.5^{\circ}N$. In the North Equatorial Current region a local upwelling was observed at $15^{\circ}N$, which brings high salinity and cooler subtropical water to the sea surface. A band of countercurrent occurs in the upwelling region between $13^{\circ}N$ and $15^{\circ}N$.