• Journal of Fisheries and Marine Sciences Education
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• v.26 no.3
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• pp.455-473
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• 2014

하계 동해의 남서부해역에 냉수가 왜 그리고 어떠한 해양환경하에 출현하는가를 밝히기 위하여 현장조사, 위성자료의 분석 및 수치실험을 실시하였다. 이 해역에서 냉수는 비정상년의 경우는 정상년에 비해 보다 더 연안 가까이에서 출현하였고, 수온도 낮았다. 이것은 냉수가 비정상년에는 정상년에 비해 크게 발달하여 연안역으로 확장함을 의미하였다. 흐름장의 계산결과는 지형류적인 관점에서 수온의 관측결과를 잘 재현하였다. 한편, 정상년의 경우는, 북한한류(NKCW)가 쓰시마난류(TC)와 균형을 유지하면서 동해의 북서쪽에 머물고 있었다. 이에 반해, 비정상년의 경우는, 북한한류가 점차 남쪽으로 남하하여 동해 서부역의 대부분이 북한한류의 세력하에 놓였다. 그래서, 하계 동해 서부 연안역에서의 냉수 출현은 남쪽으로의 북한한류의 확장에 의한 부산물인 것으로 판단되었다. 울산 연안역에 대한 유동계산결과는 하계 남풍이 불 경우, 표층과 저층 사이에 흐름의 역전현상이 나타났다. 따라서, 하계 동해의 남서부 연안역, 특히 수심의 변화가 급한 방어진 부근에서 냉수의 용승이 일어날 수 있음을 시사하였다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.166-178
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• 2015

We investigated marine environmental characteristics of Goheung coastal areas in August where is known to be the first outbreak site of Cochlodinium polykrikoides (hereafter C. polykrikoides) blooms, based on the oceanographic data observed from 1993 to 2013 around the Korean southern coastal waters including Eastern China Sea by National Fisheries Research and Development Institute (NFRDI). The data of NOAA/NGSST satellite images as well as numerical simulation results by Seo et al. [2013] were also used for analysis. Water temperatures at the surface and bottom layers in Goheung coast, i.e. Narodo, were $25.0^{\circ}C$ and $23.7^{\circ}C$ so that they were higher than $23.8^{\circ}C$ and $19.4^{\circ}C$ in Geoje coast where is a reference site, respectively. In addition, salinities at the surface and bottom layers in Goheung coast were 31.78 psu and 31.98 psu so that they were a little higher than 31.54 psu at the surface but a little lower than 32.79 psu at the bottom in Geoje coast, respectively. That is, the differences in water temperature or salinity between the surface and bottom layers in Goheung coast in August were not large compared to Geoje coast. This suggests that stratification in Goheung coast in August is fairly weak or may not be established. In addition, the concentrations of DIN and DIP at the surface layer were 0.068 mg/L ($4.86{\mu}M$) and 0.015 mg/L ($5.14{\mu}M$) in Goheung coast while 0.072 mg/L ($5.14{\mu}M$) and 0.01 mg/L ($0.32{\mu}M$) in Geoje coast, so they did not indicate a meaningful difference. On the other hand, when C. polykrikoides blooms, water temperature and salinity in August at the station 317-22 ($31.5^{\circ}N$, $124^{\circ}E$) of the East China Sea, where is near the mouth of Yangtze River, were $27.8^{\circ}C$ and 31.61 psu, respectively. Thus, water temperature was much higher whereas salinity was almost similar compared to Goheung coast. Furthermore, concentrations of $NO_3-N$ and $PO_4-P$ in the East China Sea in August were remarkably high compared to Goheung coast. When C. polykrikoides blooms, according to not only the image data of satellites NOAA/NGSST but also numerical experiment results by Seo et al.[2013], the freshwater out of Yangtze River was judged to clearly affect the Korean southern coastal waters. Therefore, the supply of nutrients in terms of Yangtze River may greatly contribute to the outbreak of C. polykrikoides blooms in Goheung coast in summer.