• 대한원격탐사학회지
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• 제38권4호
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• pp.387-394
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• 2022

Coastal upwelling is a significantly imperative process for understanding the interactions between physical and ecological processes and has been investigated incessantly. In this study, we explored the upwelling index, specifically upwelling age (UA). UA enabled us to observe the initiating, sustaining, and decaying upwelling processes. Although the sensitivity of many other geophysical parameters to estimate UA has been investigated, the wind direction has not been evaluated. Thus, we assessed the appropriate wind direction for the UA and obtained efficient upwelling signals from the four coastal stations. Furthermore, we applied the UA and compared it with the satellite sea level anomaly, sea surface temperature, and chlorophyll-a changes to validate how UA depicts their spatial extents. Thus, UA can predict the timing of coastal upwelling events using predicted geophysical parameters.

• Journal of the korean society of oceanography
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• 제38권3호
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• pp.101-110
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• 2003

We made intensive observations on the coastal upwelling off the coast of the southern East Sea from June to August in 2001. The upwelling exhibited a weekly waxing and waning. The coastal upwelling of the year 2001 was characterized by abrupt outbreaks and the small local scale. Upwelling occurred more frequently off the coast of Ulsan and Gampo as reported by the earlier observers. The spread of freshly upwelled colder water was varied by each upwelling event. Generally cold waters were carried away northeastward off Pohang province. The upwelled cold waters were saltier than the resident surface waters. The pH and salinity-normalized alkalinity support the idea that the upwelled waters originate from the interior of the East Sea. The extraordinarily high concentration of dissolved oxygen suggests that the upwelled waters are closely connected to the southward flowing North Korea Cold Current. Although a lower primary productivity was reported for the upwelling region, underway surface fluorescence measurement revealed that the recently upwelled waters supported up to an order of magnitude higher algal biomass than the ambient waters. Because thermohaline circulation of the East Sea is so vigorous, with an estimated time scale of less than one hundred years, that the coastal upwelling should be considered not as an anomaly but as a regular component of a circulatory system. A quantitative understanding of upwelling seems to be a key to elucidate material cycling and the associated biological production in the East Sea.

• 한국수산과학회지
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• 제36권6호
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• pp.723-734
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• 2003

A three-dimensional numerical model (POM) is implemented to examine coastal upwelling in the northern Japanese coastal region with the passage of Typhoon Oliwa in September 1997. Observed sea surface temperature (SST) decreased suddenly ranging from $-6\;to\;-7^{\circ}C$ in the coastal regions, and such a SST decrease state lasted for more than ten days after the typhoon passed. The model successfully reproduces the observation and gives a clear explanation, the sudden decrease of SST occurred in the process of coastal upwelling with Ekman dynamics. The model also describes the sea surface cooling in the open ocean with vertical velocity.

• 한국음향학회지
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• 제41권6호
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• pp.601-609
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• 2022

2007년 8월 동해 연안에서 연안용승 현상이 발생 되었고, 이에 따른 수직적인 수온과 염분 자료가 실시간 해양관측부이를 통해 획득되었다. 시계열 관측자료를 기반으로 연안용승 발생 전·중·후의 수직적인 음속구조를 산출하였고, 연안용승의 수평적인 규모와 실제 해저지형 등을 고려한 음향모델링을 통해 연안용승이 수중의 음파 전달과 탐지환경에 어떠한 영향을 미치는지 분석하였다. 포물선 방정식 모델을 이용한 저주파(500 Hz) 음파 전달손실과 심도별 표적 탐지거리를 비교·분석한 결과, 동해 연안에서 용승이 발생하면 그렇지 않은 일반적인 음탐환경에 비해 최대 약 10 dB의 탐지이득을 기대할 수 있는 것으로 분석되었다. 또한, 이번 연구를 통해 용승 전·후 약 2 ~ 3일의 짧은 기간 내에서도 음파전달 특성이 크게 달라질 수 있음을 확인하였다.

• Journal of the korean society of oceanography
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• 제38권3호
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• pp.122-134
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• 2003

Low-pass filtered time series of wind, coastal temperature, sea level and current were analyzed to understand the coastal upwelling processes in the southeast coast of Korea. Southerly winds favorable for coastal upwelling were dominant in summer of 1997. Total period of four major wind events amounts to 58 days during one hundred days from June to early September. Coastal temperature is most sensitive to variations of wind. The time lag between the onset of southerly (northerly) winds and decrease (increase) of temperature is 3-18 hours. In the frequency domain the coherent bands have periods of 2.4 and 4.0-5.4 days with respective phase lags of 17 and 27-37 hours. Despite the sensitive response, the magnitude of temperature change is not quantitatively proportional to the intensity or duration of the wind, because it depends on the degree of baroclinic tilting of isotherms built dynamically by the strong Tsushima Warm Current (TWC). Current is particularly strong near the coast and has a large vertical shear during the upwelling periods, which is associated with the baroclinic tilting. Both of current and sea level are poorly coherent with wind or temperature except for the period of 4 days.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.954-957
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• 2006

Satellite data (thermal and color imagery) show that offshore flowing filaments off the west coasts of North America, North and South Africa can influence significantly the cross-frontal mixing in the coastal upwelling zones. To evaluate this role, we investigated structure, dynamics and behavior of surface filaments in the Canary and Benguela upwelling regions on the base of daily satellite IR and VIS imagery (AVHRR NOAA, MODIS-Aqua). It was found that seasonal variability of the filaments location depends on intra-annual shift of general upwelling intensity along the coast. The main statistical characteristics of filaments - length, width, temperature anomaly and estimates of velocity were obtained. Estimates of cross-frontal water exchange due to filamentation based on the statistical data show that these coherent structures play a major role in the water and particle exchange between coastal zone and the open ocean in both upwelling regions.

• Ocean and Polar Research
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• 제34권2호
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• pp.111-123
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• 2012

To understand the phytoplankton community in the eastern part of the Yellow Sea (EYS), in the summer, field survey was conducted at 25 stations in June 2009, and water samples were analyzed using a epifluorescence microscopy, flow cytometry and HPLC method. The EYS could be divided into four areas by a cluster analysis, using phytoplankton group abundances: coastal mixing area, Anma-do area, transition water, and the central Yellow Sea. In the coastal mixing area, water column was well mixed vertically, and phytoplankton was dominated by diatoms, chrysophytes, dinoflagellates and nanoflagellates, showing high abundance ($>10^5\;cells\;l^{-1}$). In Anma-do coastal waters characterized by high dominance of dinoflagellates, high phytoplankton abundance and biomass separated from other coastal mixing area. The southeastern upwelling area was expanded from Jin-do to Heuksan-do, by a tidal mixing and coastal upwelling in the southern area of Manjae-do, and phytoplankton was dominated by benthic diatoms, nanoflagellates and Synechococcus group in this area. Phytoplankton abundance and biomass dominated by pico- and nanophytoplankton were low values in the transition waters and the central Yellow Sea. In the surface of the central Yellow Sea, high dominance of photosynthetic pigments, 19'-hexanoyloxyfucoxanthin and zeaxanthin implies that haptophytes and cyanobacteria could be the dominant group during the summer. These results indicate that the phytoplankton communities in the EYS were significantly affected by the formation of tidal front, thermal stratification, and coastal upwelling showing the differences of physical and chemical characteristics during the summer.

• 한국해안·해양공학회논문집
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• 제23권6호
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• pp.451-457
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• 2011

최근 용승류가 발생하는 지역에서 대규모 어장이 형성되는 원리를 이용하여 대규모 해양구조물을 건설하여 인공적으로 용승류를 발생시킴으로써 새로운 어장을 조성하는 사업이 일본과 한국에서 진행되고 있다. 이 연구에서는 FLOW-3D 모형을 이용하여 용승류 흐름을 모의하고자 하였다. 또한 FLOW-3D 모형에서 Marker의 이동을 이용하여 영양염의 용승현상을 판단할 수 있는 방법을 모색하고자 하였다. 연구결과 FLOW-3D 모형을 이용하여 용승효과를 사전에 정성적으로 판단하는 것이 가능하였다.

• 해양환경안전학회지
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• 제26권1호
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• pp.75-83
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• 2020

본 연구는 51년 장기(1967-2017년) 수온 관측자료와 ONI(Oceanic Niño Index)를 이용하여 El Niño와 La Niña가 한국 동해 연안용승 발생에 미치는 영향을 파악하였다. 수온의 시계열분석 결과 하계 연안용승 발생빈도가 동해남부(울기~감포) 연안에서 가장 높았다. 하계 ONI 가 2.5 이상 급감하는 연변동이 발생한 1987-1988년과 1997-1998년에 동해 전 연안역(부산~고성)의 수온이 4~7 ℃ 급상승하였다. ONI가 1.5 이상으로 El Niño가 강한 1987, 1997년과 ONI가 -0.8 이하로 La Niña가 강한 1988, 1998년 동해 연안역의 수온구조가 서로 다르게 나타났다. El Niño가 강한 시기 연안해역의 이상 수온은 음의 값으로 비교적 차가운 냉수괴가 분포한다. 이는 수온 경계층경사(Baroclinic tilting)가 강해 연안역의 수온 성층 형성 수심이 얕아지기 때문이다. La Niña가 강한 시기는 El Niño가 강한 시기와 반대로 이상 수온은 양의 값으로 수온이 높게 나타났다. 또한 수온의 경계층경사가 El Niño가 강한 시기에 비해 약해 수온 성층이 El Niño가 강한 시기보다 깊은 곳에 형성된다. El Niño가 강한 시기 얕은 수심에 수온성층이 형성되는 현상은 하계 남풍계열의 바람에 의한 연안용승이 발생할 확률을 높일 수 있다. 반대로 La Niña가 강한 시기에는 남풍계열의 바람이 지속적으로 불어도 연안용승이 발생할 확률이 작다. 왜냐하면, 수온성층이 El Niño가 강한 시기에 비해 깊은 수심에서 형성되기 때문이다.

• Journal of the korean society of oceanography
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• 제37권4호
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• pp.212-223
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• 2002

Cochlodinium polykrikoides bloom in 1995 was studied with a focus on an unusual coastal environment in the South Sea of Korea. Data on temperature, salinity, and zooplankton biomass during 1965-1998 and nutrients during 1990-1998 and chlorophyll-a during 1995-1998 were used in this study. These data were obtained from the serial oceanographic observations in Korean waters carried out by the National Fisheries Research and Development Institute. In 1995 the C. polykrikoides bloom began in the coastal area around Narodo Island in August and consequently occurred to the whole coastal area of the South and East Seas of Korea. During June-October 1995, the coastal environment was unusual compared with the long-term means during 1965-1998. In June 1995, sea surface temperature was 1-2$^{\circ}C$ warmer than in other years in all coastal areas, while salinity was high only to the east of Jeju Island. In August 1995, a strong coastal front appeared inshore of a line between Jeju and Tsushima Islands. In particular, a strong coastal front which showed the characteristics of upwelling front occurred in the coastal area around Narodo and Sorido Islands, not only because of a strong intrusion of the Tsushima Warm Current but also because of the upwelling of cold bottom water. Salinity was low in the neighboring waters of western side of Jeju Island. Nutrients and chlorophyll-a were high in the inshore area between Narodo and Sorido Islands in 1995 in contrast with the other years and areas. Zooplankton showed an unusually high abundance in the coastal area in October 1995. We conclude that the Tsushima Warm Current strongly influenced the South Sea of Korea in 1995 and created strong upwelling front bordering cold upwelled water in the coastal area around Narodo and Sorido Islands. It leads us that these physical structures introduce the favorable environment for the development of C. polykrikoides blooms. We suggest that C. polykrikoides has a bio-physical tolerance of high shear and stress and prefers frontal and upwelling relaxed areas as its habitat. We also find that nutrients were not supplied to the coastal area from the offshore where a low salinity water mass with high nutrients appeared around Jeju Island. Because the strong upwelling front protect the reach of offshore low saline water mass. The main source of nutrients was the upwelled water mass in the coastal area of Wando-Narodo-Sorido.