• Ocean Science Journal
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• 제40권2호
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• pp.67-78
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• 2005

Complex physical, chemical and biological interactions off the Korean coast created several striking patterns in the phytoplankton blooms, which became conspicuous during the measurements of ocean color from space. This study concentrated on analyzing the spatial and temporal aspects of phytoplankton chlorophyll variability in these areas using an integrated dataset from a Sea-viewing Wide Field-of-view Sensor (SeaWiFS), Advanced Very High Resolution (AVHRR) sensor, and Conductivity Temperature Depth (CTD) sensor. The results showed that chlorophyll concentrations were elevated in coastal and open ocean regions, with strong summer and fall blooms, which appeared to spread out in most of the enclosed bays and neighboring waters due to certain oceanographic processes. The chlorophyll concentration was observed to range between 3 and $54\;mg\;m^{-3}$ inside Jin-hae Bay and adjacent coastal bays and 0.5 and $8\;mg\;m^{-3}$ in the southeast sea offshore waters, this gradual decrease towards oceanic waters suggested physical transports of phytoplankton blooms from the shallow shelves to slope waters through the influence of the Tsushima Warm Current (TWC) along the Tsushima Strait. Horizontal distribution of potential temperature $(\theta)$ and salinity (S) of water off the southeastern coast exhibited cold and low saline surface water $(\theta and warm and high saline subsurface water $({\theta}>12^{\circ}C; S>34.4)$ at 75dBar, corroborating TWC intrusion along the Tsushima Strait. An eastward branch of this current was called the East Korean Warm Current (EKWC), tracked with the help of CTD data and satellite-derived sea surface temperature, which often influenced the dynamics of mesoscale anticyclonic eddy fields off the Korean east coast during the summer season. The process of such mesoscale anticyclonic eddy features might have produced interior upwelling that could have shoaled and steepened the nutricline, enhancing phytoplankton population by advection or diffusion of nutrients in the vicinity of Ulleungdo in the East Sea.

• Ocean Science Journal
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• 제42권2호
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• pp.103-116
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• 2007

Seasonal changes of tide signal(s), temperature, salinity and current were studied during the years 2004-2005 in the northernmost Gulf of Aqaba, which is under developmental activities, to obtain scientific bases for best management and sustainability. Spectrum analysis revealed permanent signals of tide measurements during all seasons, which represented semidiurnal and diurnal barotropic tides. The other signal periods of 8.13, 6.10-6.32, 4.16 and 1.02-1.05 h were not detected in all seasons, which were related to shallow water compound and overtides of principle solar and lunar constituent and to seiches generated in the Red Sea and the Gulf of Aqaba. Spatial and temporal distribution of temperature, salinity and density showed significant differences between months in the coastal and offshore region and no significant differences among the coastal sites, between the surface and bottom waters and between coastal and offshore waters. Therefore, the temporal and spatial variation of water properties in the northernmost Gulf of Aqaba behave similarly compared to other parts. The coastal current below 12 m depth was weak $(3-6\;cms^{-1})$ and fluctuated from east-northeastward to west-southwestward (parallel to the shoreline), which may be related to the effect of bottom topography and/or current density due to differential cooling between eastern and western parts in the study area, and wind-induced upwelling and downwelling in the eastern and western side, respectively. The prevailing northerly winds and stratification conditions during summer were the main causes of the southward current at 6 and 12 m depths with average speed of 28 and $12cms^{-1}$ respectively.

• 한국해양학회지:바다
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• 제28권4호
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• pp.158-177
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• 2023

하구역은 강과 하천을 통해 육상과 해양을 연결하는 전이수역으로 해양으로 공급되는 많은 물질들은 연안환경의 일차 생산성을 결정하는 중요한 역할을 담당하며, 이러한 연안생태계는 생물량에 의해 제거되는 탄소인 블루카본의 탄소 저장소로서 기후변화를 완화시키는 역할을 한다. 우리나라의 서-남해 하구역(한강, 금강, 영산강, 섬진강, 낙동강)과 동해 용승해역에서 지난 6년간 표층퇴적물의 평균입도와 유기탄소 함량의 변화와 두 인자들 사이의 상관관계를 분석하였다. 조사기간(2015-2020년) 동안 서-남해 하구역과 동해 용승해역 표층퇴적물의 평균입도와 유기탄소 함량은 계절적 변화가 관찰되지 않았으며, 전반적으로 각 해역의 다양한 해양환경 및 수리역학적 조건에 의해 두 인자들이 조절되는 것으로 해석된다. 조사된 모든 시료채취의 동시성이 없는 문제점에도 불구하고 연구지역에서 분석된 모든 퇴적물 평균입도들의 평균값과 유기탄소 함량의 평균값은 양의 상관관계를 보이며 각 하구역과 동해 용승해역을 구분한다. 동일한 양의 상관관계를 보이는 각 하구역에서는 아마도 같은 과정에 의한 퇴적물 점토입자의 퇴적이 유기탄소 축적에 중요한 역할을 담당한다. 그러나 동해 용승해역은 하구역과 다르게 추가적인 유기탄소 축적의 요인이 나타난다. 국내 주요 하구역들이 연안환경에서 중요한 탄소저장소로서 평가되기 위해서는 탄소 저장량 계산을 위한 추가적인 자료(퇴적률, 전밀도 등)가 요구된다.

• 한국해양학회지:바다
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• 제14권3호
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• pp.127-133
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• 2009

동해 울릉분지에서 망간산화물과 철산화물의 유기물 분해 기여율을 정량화하기 위하여 6개의 박스형 시추퇴적물을 채집하였다. 수심이 2,000 m 이상인 울릉분지 표층퇴적물에서 유기탄소 함량은 2.6% 가량으로 육상기원 유기물 유입이 많은 흑해와 용승 해역인 칠레 주변해역들과 비슷했다. 울릉분지에 위치한 정점들에서 망간산화물 함량은 퇴적물 최상부에서 2% 이상으로 매우 높았고, 철산화물 함량은 울릉분지 표층 $1{\sim}4cm$ 내외에서 2% 가량의 최고값을 나타냈다. 그러나 대륙사면 정점들에서 망간산화물과 철산화물 함량은 분지처럼 높은 값을 보이지 않았다. 동해 울릉분지에서 2% 이상으로 높은 망간산화물 함량은 높은 유기탄소 함량과 사면보다 비교적 느린 퇴적속도 때문이거나 망간 이온이 저탁류를 통해 사면에서 분지로 이동한 것으로 예상된다. 망간산화물 환원율은 $0.3{\sim}0.57\;mmol\;m^{-2}\;day^{-1}$의 범위를 보였고, 철산화물 환원율은 $0.10{\sim}0.24\;mmol\;m^{-2}\;day^{-1}$의 범위를 나타냈다. 울릉분지에서 금속산화물은 유기물 분해에 $13{\sim}26%$ 정도를 차지하였으며, 이는 칠레 용승 해역과 유사하고, 덴마크 연안보다 낮은 값이다.

• 수산해양기술연구
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• 제56권1호
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• pp.11-17
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• 2020

The occurrence of eggs of hairtail, Trichiurus japonicus was examined in the coastal waters of Jeju Island, Korea in spring from May to June in 2014, April to May in 2015, and April to in 2016. As a whole, hairtail eggs occurred abundantly in May, 2014. Especially, high densities over 300 ind./1,000 ㎥ of eggs abundances in May and June, 2014 occurred in the north-western area of Jeju Island where is upwelling phenomenon occurred throughout the year. In the relationship between T-S and the hairtail eggs abundances, high densities over 100 ind./1,000 ㎥ of eggs abundances occurred in temperature of 18.1-18.7℃ and salinity of 33.92-34.87‰ in May when hairtail eggs occurred abundantly.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.918-921
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• 2006

The short-term variation of sea surface temperature before and after typhoons and increase of chlorophyll a concentration that accompany with the typhoons during summer in the East/Japan Sea were explored by satellite. Four typhoons (NAMTHEUN, MEGI, CHABA and SONGDA) and a typhoon (NABI) passed over the East/Japan Sea in 2004 and 2005, respectively. Decreasing of SST was observed in the every five typhoons, however the magnitude of SST decreasing were various from 1 to $5^{\circ}C$. Chlorophyll a increases were found after the typhoons (0.1-3 ${\mu}g$ $l^{-1})$ except NAMTHEUN, and the area was approximately included in SST decreasing area by the typhoons. It suggests that chlorophyll a increase was caused by nutrient input from subsurface layer by strong mixing. On the other hand, rarely chlorophyll a increase was observed in northern area of polar frontal zone, which is located in $38-41^{\circ}N$, than northern area, and chlorophyll a increase in coastal area was higher (more than 3 times) than offshore area. It might suggest that chlorophyll a increase in the East/Japan Sea is also related with the depth or nitracline depth that affects the amount of nutrients supply to the upper layer by typhoon mixing.

• Journal of the korean society of oceanography
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• 제33권3호
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• pp.53-63
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• 1998

The Princeton ocean model (POM) with free surface in sigma-coordinate, governed by primitive equations, is used to examine the response of sea water in Deukryang Bay to a typhoon. The model reproduces reasonably well the main features in the wind-driven dynamics due to passing of a typhoon. In response to the wind, the coastal jet develops and the upwelling(or downwelling) occurs dominantly in both sides of the bay. This result implies that there should be an overturn in the bay water with the passing of typhoons. Numerical results of POM are also compared to those of a depth-averaged model. From the comparison, it is postulated that the bottom drag coefficient conventionally used for the two-dimensional flow models is inadequate due to overestimation of the computed current field.

• Ocean and Polar Research
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• 제24권2호
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• pp.135-146
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• 2002

The upper ocean in the western equatorial Pacific warm pool during TOGA-COARE IMET IOP was simulated using a one-dimensional turbulence closure ocean mixed-layer model, which considered recent observations, such as the remarkable enhancement of turbulent kinetic energy near the ocean surface. The shoaling/deepening of the mixed layer and warming/cooling subsurface water in the model were in reasonable agreement with the observations. There was a significant improvement in simulating the cooling trend of the sea surface temperature under a westerly wind burst with heavy rainfall over previous simulations using bulk mixed-layer models. By contrast the simulated sea surface salinity (SSS) departed significantly from the observed SSS, especially during a westerly burst and the subsequent restratification period, which might be due to 3-D control processes, such as downwelling/upwelling or advection.

• Ocean and Polar Research
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• 제41권4호
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• pp.213-232
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• 2019

This study evaluates the accuracy of four satellite-composite (OSTIA, AVHRR, G1SST, FNMONC-S) and three model-reanalysis (HYCOM, JCOPE2, FNMOC-M) daily sea surface temperature (SST) data around the Korean Peninsula (KP) using ocean buoy data from 2011-2016. The results reveal that OSTIA has the lowest root mean square error (RMSE; 0.68℃) and FNMOC-S/M has the highest correction coefficients (r = 0.993) compared with observations, while G1SST, JCOPE2, and AVHRR have relatively larger RMSEs and smaller correlations. The large RMSEs were found in the western coastal regions of the KP where water depth is shallow and tides are strong, such as Chilbaldo and Deokjeokdo, while low RMSEs were found in the East Sea and open oceans where water depth is relatively deep such as Donghae, Ulleungdo, and Marado. We found that the main sources of the large RMSEs, sometimes reaching up to 5℃, in SST data around the KP, can be attributed to rapid SST changes during events of strong tidal mixing, upwelling, and typhoon-induced mixing. The errors in the background SST fields which are used in data assimilations and satellite composites and the missing in-situ observations are also potential sources of large SST errors. These results suggest that both satellite and reanalysis SST data, which are believed to be true observation-based data, sometimes, can have significant inherent errors in specific regions around the KP and thus the use of such SST products should proceed with caution particularly when the aforementioned events occur.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2008년도 춘계학술발표회
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• pp.169-171
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• 2008

본 연구에서는 위성관측 해양표면수온과 클로로필 영상 및 현장관측 자료를 이용하여 동해남부 냉수대 발생 주변해역의 단기변동을 조사하였다. 특히 본 연구에서는 2007년 8월 하계 계절풍 기간 동안의 동한난류 주변의 해양표면수온과 클로로필의 공간변동에 주목하였다. 본 연구기간에 조사한 동한난류 해역의 해양표면수온과 클로로필의 공간분포는 (1) 연안 냉수대해역, (2) 수온전선의 냉수대해역, (3) 동한난류해역, (4) 외해 냉수해역으로 구분할 수 있었다.