Observations of Southeastward Deep Currents off the East Coast of Korea

이흥재,석문식,김철호,Lie, Heung-Jae,Suk, Moon-Sik,Kim, Cheolho The Korean Society of Oceanography 1989 韓國海洋學會誌 Vol.24 No.2

Deep current was observed at 620 m and 790 m in water 840 m deep off the mid-east coast of Korea from August 26 to November 7, 1986. Data analysis showed that the deep current in the subinertial frequency range was directed to southeast with a vector-average speed of about 3 cm/s. The deep flow had a large temporal variability with the same pattern of variation at the two depths. The maximum speed of the low-frequency current reached to a value larger than 11 cm/s just after the passage of Typhoon Vera over the study area. We also observed occurrence of sharp direction changes from southeast toward north persisting for a few days.

黃海水 와 循環에 관한 考察

이흥재,Lie, Heung-Jae 한국해양학회 1984 韓國海洋學會誌 Vol.19 No.2

Water masses and circulation in the yellow Sea (Hwanghae) were briefly reviewed and synthesized. Water masses were classified into four types: Hwanghae Cold Water, Hwanghae Warm Current Water, Coastal Waters and Changjiang River Diluted Water. The Hwanghae Cold Water can be defined to have a salinity of 32.0∼33.0% and a temperature below 10$^{\circ}C$, based on long-term hydrographic data and recent CTD casts (KORI, 1984). Concerning circulation, there exists a cyclonic gyre throughout the year in the southern part. In winter, the coastal current along the Chinese coast is very strong due to northerly or northwesterly winds and the Hwanghae Warm Current becomes weak as can be expected from a surface to bottom thermohaline front west of Cheju-do. Meanwhile in summer, the Changjiang River Diluted Water flows northeastward toward Cheju-do and the coastal current in the western part is greatly reduced. The northward current during summer in the southeastern Hwanghae has been accepted to be the Hwanghae Warm Current until now, coastal waters and the Hwanghae Cold Water in the central deep area, not a continuation of the Hwanghae Warm Current.

위성추적부이를 이용한 새만금 유출수 이동경로 및 특성에 관한 연구

임은표(Lim Eun-Pyo),이흥재(Lie Heung-Jae),조철호(Cho Cheol-Ho),이석(Lee Seok) 한국마린엔지니어링학회 2008 한국마린엔지니어링학회 학술대회 논문집 Vol.2008 No.-

We analyzed the change of behavior and characteristic of sluice gates outflow water caused by the construction of Saemangeum dike, based on field observation using by TGPS. Saemangeum dike was completed in April 2006. Before closure of dike, the distance of outflow is 12㎞ ~ 14㎞ during one tidal cycle also mean speed is 1.5㎧. After closure of dike, the tidal range in outside of the dike decreased slightly but significantly and the tidal current in outside of the dike decreased about 50 percent. So the distance of outflow and mean speed decreased about 3㎞ and 0.1㎧s respectively.

위성추적부이를 이용한 새만금 유출수 이동경로 및 특성에 관한 연구

임은표(Lim Eun-Pyo),이흥재(Lie Heung-Jae),조철호(Cho Cheol-Ho),이석(Lee Seok) 한국항해항만학회 2008 한국항해항만학회 학술대회논문집 Vol.2008 No.공동학술

We analyzed the change of behavior and characteristic of sluice gates outflow water caused by the construction of Saemangeum dike, based on field observation using by TGPS. Saemangeum dike was completed in April 2006. Before closure of dike, the distance of outflow is 12km ~ 14km during one tidal cycle also mean speed is 1.5m/s. After closure of dike, the tidal range in outside of the dike decreased slightly but significantly and the tidal current in outside of the dike decreased about 50 percent. So the distance of outflow and mean speed decreased about 3km and 0.1m/s respectively.

해수면 관측레이더의 국내 현황 및 운용에 관한 보고

송규민(Song, Kyu-Min),조철호(Cho, Chol-Ho),정경태(Jung, Kyung-Tae),이흥재(Lie, Heung-Jae) 한국해안해양공학회 2010 한국해안해양공학회 논문집 Vol.22 No.6

전 세계적으로 환경, 해양, 기상, 기후, 해상 및 재난예방을 지원하기 위한 해수면 조사를 위하여 해양레이더를 운용하고 있으며, 국내에서도 해양유출유와 방조제 유출수 조사 및 해상안전사고 예방을 위하여 13, 25, 42 MHz 대역의 레이더를 6개 지역에서 운용하고 있다. 그러나 측정단파대역을 이용하는 해양레이더는 실험국으로 허가받아 관리되어지고 있으며, 오늘날 주파수 분배가 논의 되고 있다. 해양레이더 주파수 분배를 위한 조사에 의하면 3~50 MHz의 국내 전파환경은 20 MHz 이상의 대역에서 레이더운용에 문제가 없으나 13 MHz를 제외한 20 MHz 이하대역은 사용검토가 필요하다. 국내 사용자는 해양레이더의 운용과 자료처리 기법에 국내의 주파수 환경을 충분히 고려해야 한다. There is increasing interest, on the global basis, in the operation of ocean surface radars for measurement of coastal sea surface conditions to support environmental, oceanographic, meteorological, climatological, maritime and disaster mitigation operations. In south Korea, ocean surface radars are operating to monitoring oil spill, outflow from dike or preventing from safety-accidents in the 6 regions (16 radial sites) by main frequency about 13, 25 and 42 MHz until the present. However, that ocean surface radars have been operated on an experimental spectrum basis. In the results of 3~50 MHz band domestic analysis to improve the regulatory status of the spectrum used by oceanographic radars, it was demonstrated that sufficient frequency bands are available for oceanographic radars on the frequency band above 20 MHz. It is difficult to deploy and operate oceanographic radars in the sub-bands below 20 MHz except for 13 MHz band. For using HF ocean surface radars one should understand the spectrum environment in Korea and should prepare a suitable operating system and data processing techniques.

동중국해 외대륙붕 저층수의 영양염 기원

정창수(Chang Soo Chung),홍기훈(Gi Hoon Hong),김석현(Suk Hyun Kim),김영일(Yong Il Kim),문덕수(Duk Soo Moon),박준건(Jun Kun Park),박용철(Yong Chul Park),이재학(Jae Hak Lee),이흥재(Heung Jae Lie) 한국해양환경·에너지학회 2000 한국해양환경·에너지학회지 Vol.3 No.3

VARIATIONS OF WATER TURBIDITY IN KOREAN WATERS

이흥재,Yu Hwan Ahn,Jeong Eon Moon 한국해안해양공학회 1999 학술강연회 발표논문초록집 Vol.1 No.1

An algorithm model for total suspended sediments is developed using normalized water leaving radiance at 555㎚ in the SeaWiFS band 5. And the model is compared with the empirically derived algorithm from in-situ measurements. Using the new algorithm, the water turbidity in Korean waters was analyzed for the first time for the SeaWiFS data. The turbidity images were used in the general study of suspended sediment (SS) distribution at the Yellow Sea, the South Sea and of water mass movement in coastal area, especially for the waters of estuaries. Satellite images showed large spatial variance in suspended sediment distributions. High turbidity always appeares at the estuaries of Han River, along the Taean peninsula and coastal areas of Jin-do for the Korean side and the Yantze River estuary and adjacent seas and Shandong peninsula for the Chinese side. The SS values range between 3 - 50g/㎥ in coastal areas and 1-5g/㎥in open seas. Most turbid region was observed along the Jin-do where maximum SS concentration reaches 100 g/㎥. Interestingly, the waters of Yantze River estuary and the shelf waters of East China Sea extent to the west part of Cheju Island and mixed with the waters of South Sea, and a comparison of SS with sea surface temperature does not support the existence of Yellow Sea Warm Current.

Temporal and Spatial Characteristic of Sea Surface Winds over the Adjacent Seas of Korean Peninsula : Spectral Analysis

이흥재,Jung Yul Na,Song Kyu Han 한국해안해양공학회 1995 학술강연회 발표논문초록집 Vol.1 No.1

IN THE YELLOW SEA WARM CURRENT A PERSISTENT MEAN FLOW ?

Jae Hak Lee,이흥재,Yu Xiang Tang,Suk Lee,Cheol Ho Cho 한국해안해양공학회 1999 학술강연회 발표논문초록집 Vol.1 No.1

Existence of the Yellow Sea Warm Current is discussed by analyzing comprehensive CTD data collected by a Korea-China joint study during 1996 to 1998, together with trajectories of satellite-tracked drifters. Saline water is observed to exist on the western flank of the central trough of the Yellow Sea throughout the year, which should come from the East China Sea. This saline water is classified as a mixed water of fresh coastal water and the saline Cheju Warm Current water having salinity greater than 34.0 psu (Lie et al., 1999). In winter, the mixed water is distributed in a tongue shape as if its root face the Cheju Warm Current water west of Cheju-do, while in summer, it is completely isolated in the lower layer of the Yellow Sea interior. Salinity of the isolated mixed water gradually decreases from late spring to late autumn. Most drifters in the western area of Cheju-do rounded Cheju-do clockwise to move into the Cheju Strait rather than moving into the southwestern Yellow Sea. Previous studies commonly suggest the persistent existence of the Yellow Sea Warm Current transporting Kuroshio-origin saline water into the southern Yellow Sea, but our observations show that saline water in the western area of Cheju-do does not intrude into the southwestern YS during the summer monsoon. Daily mean currents estimated from the drifter trajectories are very weak unexpectedly during the winter monsoon and do not show a continuous intrusion of saline water into the southwestern YS, although a tongue shaped mixed water exist there. Therefore, it is thought that the northwest intrusion may take place intermittently during the winter monsoon when the strong northerly winds prevail.

SEASONAL VARIABILITY OF WATER BALANCE IN THE YELLOW SEA

Jae Hak Lee,이흥재,Byoung Woong An,Yu Xiang Tang 한국해안해양공학회 1999 학술강연회 발표논문초록집 Vol.1 No.1

We analyze the CTD data obtained in the Yellow Sea through a Korea-China joint project during 1996-1998. Most of water masses analyzed here show that the seasonal variation is dominant. It is found that the low salinity core waters are formed in the southern surface layer in mid summer and their seasonal distribution exhibit a well posed annual cycle. Overall distribution patterns indicate that the low salinity core waters drift like a single body to adjust the seasonal basin-scale pressure fields, implying an eddy-like system. Another founding is that the temporal intermediate water characterized by its temperature minimum appears in the region of 50 m depth in the western Yellow Sea in spring. This water might be the remnants of cold waters formed during the winter season and the temperature minimum core appears as a result of different tidal mixing. Summertime data indicate that warm and saline waters provided from the southeast into the southern Yellow Sea in winter are isolated in the bottom layer of the region in summer, which modify continuously. In the future it is very necessary to study water masses in the bottom layer in summer to clarify the variation of the Yellow Sea Warm Current.