하계 동해에 있어서 대마난류의 북상한계와 변동

홍철훈,조규대,Hong, Chol-Hoon,Cho, Kyu-Dae 한국해양학회 1983 韓國海洋學會誌 Vol.18 No.1

The northern boundary of the Tsusgima Current and its fluctuations are divcussed in the Japan Sea in summer. This current was characterized with high slinity, and its path was traced by following the salinity maximum on the basis of oceanographical data collected during the period from 1963 to 1979. The salinity maxima (34.45-34.85 ) of the Tsushima Current in the areas between 29 N in the East China Sea and northern part of the Japan Sea were found at depths between 46m and 135m. The representative thermosteric anomaly corresponding to the salinity maximum eas examined in order to analyze the advection of this currint. In the Tsushima Current region in the Japan Sen, the thermosteric anomaly values in the layer of salinity maximum during the period of 1970 to 1979 was beween 220 cl/t and 260 cl/t. In general, as the current moves northward its salinity decreascs, its thermosteric anomaly decreases and the depth of salinity maximum becomes shallower. The northern boundary of this current, which is indicated by 34.4 isohaline on 240 cl/t isanosteric surface during the study period of ten years, was confined to south of 40 N of the Japan Sea. The 34.4 isohaline edvealed two types of flow; one of them flows northward along the eastern coast of South Korea and then meanders eastward, while the oter flows basically northeastward along the coast of Japan. The meanders of northern boundary of this currint idrntified th isohaline in this word were nearly similar to those studied by others on the bases of isotherm analysis.

1981年 夏季 東海沿岸域의 異常底水溫現象

홍철훈,조규대,양성기,Hong, Chol-Hoon,Cho, Kyu-Dae,Yang, Sung-Ki 한국해양학회 1984 韓國海洋學會誌 Vol.19 No.1

The abnormal cooling phenomenon occurred in the coastal areas of East Sea of Korea in summer, 1981 is studied on the basis of the oceanographical data obtained by the National Fisheries University of Pusan, in July, 1981 and by Fisheries Research and Development Agency of Korea during 1961 to 1981 and by Japan Meteorological Agency in 1975 and 1981. Th vertical section of temperature along 130 E showed that the warmer waters more than 10 C occupied at upper layer of about 75m depth in south of 35 30'N the layer changed rapidly thinner as 20m th 30m depth. In the areas of East Sea during 1966 to 1981, the temperature fluctuations at 100m depth ranged greatly in standard deviation from 2 C to 4 C. The temperature anomaly in 1981 was about 1.5 times of the standard deviation and at the upper layer of 150m depth the temperatures became colder by 5 -10 C than average values in August, 1961-1975. The 10 C isotherm at 100m depth in 1981 appeared between 35 and 36 N, shifting southward 20 to 120 miles than mean year. These results showed that the abnormal cooling phenomenon in the areas of East Sea of Korea in summer occurred mose predominantly in 1981 in period from 1966 to 1981

An Effect of Layered Earth on Magnetotelluric Responses of Three-Dimensional Bodies

김희준,홍철훈,Kim, Hee Joon,Hong, Chol Hoon The Korean Society of Economic and Environmental G 1994 자원환경지질 Vol.27 No.5

2층구조 대지속에 존재하는 유한 크기의 불균질체로 인한 지자기 지전류 (MT) 응답을 적분방정식법으로 계산하였다. 적분방정식은 입사전자장과 3차원물체 내부의 산란전류를 층상대지에 적합한 전기적 텐서 그린함수를 통하여 연결시킨다. 본 논문에서는 3차원체의 MT응답에 미치는 표층과 기반층의 영향에 대하여 검토하였다. 표층은 탐사대상물의 검출을 방해하는 효과를 가지며 그 효과는 표층의 전기비저항이 높을 때보다 낮을 때가 더 뚜렷하다. 한편 기반은 상층의 3차원체에 인한 MT이상을 높이는 효과를 가져올 수도 있다. 전기비저항이 높은 기반이 존재하면 물체에 의한 전류의 미소변동은 보다 전기비저항이 낮은 상층에 한정되는 경향이 있다. The integral equation method is used for magnetotelluric (MT) modeling of a finite inhomogeneity in a two-layered earth. An integral equation relates the incident plane-wave field and the scattering currents in the three-dimensional (3-D) inhomogeneity through the electric tensor Green's function appropriate to a layered earth. This paper describes an effect of overburden and basement on MT responses of 3-D body. The effect of overburden is to reduce the detectability of target, and the reduction of detectability is more apparent for conductive overburden than for resistive one. The effect of basement, on the other hand, may enhance the anomaly due to 3-D body in the upper layer. In case of the resistive basement current perturbations about the body tend to be confined to the more conductive upper layer.

1981年 夏季 黃海底層冷水의 理想底水溫現象

양성기,조규대,홍철훈,Yang, Sung-Ki,Cho, Kyu-Dae,Hong, Chol-Hoon 한국해양학회 1984 韓國海洋學會誌 Vol.19 No.2

The abnormal low water temperature phenomenon of the Yellow Sea Bottom Cold Water in summer, 1981 is studied on the basis of the oceanographical data collected by the National Fisheries University of Pusan in July, 1981 and Fisheries Research and Development Agency of Korea from 1960 to 1981 and meteorological data within the same 22 years. In winter, 1980 the northwesterly monsoon was vary predominant and the air temperature was lower than that of mean year by 1∼8$^{\circ}C$ and also the surface temperature was lower 1∼3$^{\circ}C$. And then the temperature of the Yellow Sea Bottom Cold Water in summer, 1981 became lower 2∼3$^{\circ}C$ than that of mean year and the influence of this cold water was extended to about 50 miles off the coast of Cheju Island. Comparing with mean year, the water temperature at 30m depth in February, 1981 was lower by 1∼2$^{\circ}C$ in entire regions except near sea of Sohuksando and at 50m depth in August, 1981, it was lower by about 3.5$^{\circ}C$. Particularly, the offshore of Hongdo shower value of 5$^{\circ}C$ than that of mean year. It was found that the abnormal low water temperature phenomenon of Yellow Sea Bottom Cold Water in summer, 1981 resulted from the sea surface cooling by the predominant northwestly monsoon and abnormally low air temperature in winter, 1980.

고등어 어획량(漁獲量) 변동(變動)에 따른 동지나해(東支那海)의 어장(漁場)과 해황(海況)

조규대 ( Kyu Dae Cho ),홍철훈 ( Chol Hoon Hong ),김용문 ( Yong Moon Kim ) 한국어업기술학회 1984 수산해양기술연구 Vol.20 No.2

하계 득량만의 연직혼합과 관련된 바람(태풍), 조석, 태양에너지의 영향

이병걸 ( Byung Gul Lee ),조규대 ( Kyu Dae Cho ),홍철훈 ( Chol Hoon Hong ) 한국어업기술학회 1995 수산해양기술연구 Vol.31 No.3

동지나해·황해의 부세어장과 해황과의 관계

홍철훈 한국수산학회 1985 한국수산과학회지 Vol.18 No.1

동지나해·황해의 안강망에 의한 어획통계 자료 (1967∼1979) 및 해양관측 자료를 이용하여 부세의 어획량, 어장의 변동과 수온 구조와의 관계를 조사하였다. 그 결과 부세의 주요 어장은 제주도 남서방해역에 집중하였으며, 주어기는 4월이었다. 또한 CPUE는 50㎏/haul 이상의 해역이 거의 없어 전반적으로 어장이 좋지 않았으며, 변동계수(C.V.)도 컸다. 특히 주어기인 4월에는 수심 50m의 10∼8℃등온선역에 어장이 분포하였고, 같은 민어과인 참조기·강달이 등에 비해 냉수측에 분포하였다. The relationship between the fishing grounds of Buse, Pseudosciaena crocea (Richardson), and oceanographic condition in the Yellow Sea and the East China Sea is studied on the basis of the data of the catches of stow net fishery (Fisheries Research and Development Agency, 1967∼1979) and the oceanographic observation data. The main fishing grounds of the Buse was concentrated in southwestern area of Cheju island and the best catch was in April. CPUE was less than 50㎏/haul in the most part of fishing grounds, therefore the conditions of fishing grounds generally were poor and coefficients of variance were also large. In the main fishing period, April, the fishing grounds were generally distributed in colder region of 8℃ through 10℃ isotherm at 50m depth, than Yellow croaker and Gangdali which were distributed between 10℃ and 15℃.

동해연안역 해수면변동에 미치는 태풍의 영향 : Ⅰ . 일본 북부연안에서의 해수면변동 part Ⅰ . The Response on the North Japanese Coast

홍철훈,윤종환 한국수산학회 1993 한국수산과학회지 Vol.26 No.6

태풍통과시 동해의 일본북구연안에서의 수위변동을 조사하기 위해 1966∼1986년간의 시간별수위자료분석 및 고분해능(5′×5′)을 갖는 천해파모델상에서의 수치실험을 행하였다. 자료분석의 주결과는 1) 태풍통과시 Simonoseki(SS)와 Maizuru(MZ) 간에 약 4 ㎧의 위상속도를 갖는 진행파가 존재하나, 2) Sasebo(SB)와 Hakata(HK) 간에는 파속이 매우 느리고(약 1.7 ㎧), 3) HK에서는 SS에 비해 약 반나절 늦게 최대수위에 도달하는 점등이었다. 실험결과는 관측결과와 좋은 대응을 보였다. 실험결과로 볼 때, 연안에 전파하는 진행파는 관측결과와 거의 같은 위상속도 약 4 ㎧를 갖는 지형성파로서 확인된다. 태풍이 대한해협을 통과하기 전에는 일본연안에 평행한 바람에 의해 생성된 남서방향의 연안젯트류에 의해 파의 전파가 영향을 받고, 태풍이 통과한 후에는 연안젯트류가 약해지면서 파가 전파하게 된다. The response of sea levels to a typhoon in the north Japanese coast in the Japan Sea is investigated by using hourly ses level data(1966∼1986) and a numerical shallow water model with high resolution(5′×5′). The observed sea level analysis shows (1) progressive waves exist between Simonoseki(SS) and Maiauru(MZ) with the mean phase speed of about 4 ㎧ during the passage of the typhoon, (2) the phase speed between Sasebo(SB) and HK(Hakata) is slower(about 1.7 ㎧), and (3) the maximum sea level at HK is achieved about 0.5 day later than that of SS. In many aspects, the numerical model results correspond well to the above observed features. In the model the progressive waves are identified as a topographic wave with the phase speed of about 4 ㎧. Before the typhoon passes through the Korea Strait/ the Tsushima Strait, the wave propagations along the Japanese coast are significantly influenced by the southwestward coastal jet induced by the wind stress parallel to the coast. The waves start to propagate northeastward along the coast when the coastal jet is weakened.

득량만의 해수유동에 관한 수치실험 : 1 . M2 조에 의한 해수유동 1 . Tidal Circulation forced by M2 - tide

조규대,홍철훈,정은진,이병걸 한국수산학회 1994 한국수산과학회지 Vol.27 No.4

Circulations in Deukryang Bay are investigated using a numerical shallow water model. In the flow fields observed at four stations, north-south velocity components are dominant. In the model, the circulation forced by M₂-tide basically corresponded well to the observations. The model shows the strong currents in the mouth and the eastern part in the bay with about 60㎝/s and 50㎝/s, respectively. The model also shows the eddies in the tidal residual currents. To investigate the mechanism of eddy formation some numerical experiments are carried out. The results show that inertial and topographic effects play an important role in the eddy formation.

하계 동해의 용존산소 분포특성과 대마난류

조규대,홍철훈 한국수산학회 1983 한국수산과학회지 Vol.16 No.3

高溫·高鹽水인 對馬暖流는 동해에서 하계에 염분 최대층을 형성한다. 또 이 염분최대층의 용존산소(4.0∼5.5 ㎖/ℓ)는 고산소인 東海固有水 (6.0∼8.5㎖/ℓ)에 비해 적은 값을 보이고 있는 것이 특징이다. 하계 東海에서 對馬暖流가 변동함에 따른 용존산소의 분포특성과 그 변동을 파악하기 위하여, 용존 산소의 연직구조에 따라 그 분포역을 구분하고 염분 최대층에서 용존산소를 조사하여 연직단면구조의 변화를 검토하였다. 그 결과는 다음과 같다. 용존산소의 분포역은 해에 따라 다소 변동은 있으나 크게 셋으로 구분되었다. 즉 쿠로시오의 성질을 거의 그대로 보이는 36°N이 남해역, 동해 고유수의 성질을 보이는 해역(40°N 이북해역) 및 그 중간해역인 對馬暖流域(36°N∼40°N)이었다. 염분최대치가 나타나는 층에서의 용존산소 및 δ_T(thermosteric anomaly)의 범위는 대체로 4.9∼6.5㎖/ℓ, 210∼240 cl/t 이었으나, 그 최대빈도는 각각 5.5∼5.7㎖/ℓ, 230∼240 cl/t 이었다. 對馬暖流가 한국 동해안쪽으로 치우쳐 북상한 해의 경우에는 냉수와의 경계역에서 蛇行이 심하나 일본 연안쪽으로 主流가 북상한 해의 경우는 냉수와의 경계역이 매우 남하해 있고 비교적 전자에 비해 사행도 적었으며, PM 선상의 단면도로 볼 때 주축이 외해쪽으로 좀 더 이동해 있는 것으로 나타났다. 한편 용존산소의 분포상태로써 對馬暖流의 북상한계를 파악할 수가 있었다. This paper describes the variations of the distribution of dissolved oxygen in the Japan Sea in summer during 1974-1977. In the Tsushima Current region of the Japan Sea the salinity maxima appears frequently in summer and the dissolved oxygen at the salinity maximum is less than that in the Japan Sea Proper Water. The Japan Sea is divided into three parts with respect to the type of vertical profiles of dissolved oxygen: The southern region of about 35˚N which has low dissolved oxygen similar to those in the Kuroshio region, the Japan Sea Proper Water region, and the area between about 36˚N and 40˚N which has high dissolved oxygen. The ranges of the dissolved oxygen and thermosteric anomaly(δ_T) at the salinity maximum are roughly between 4.9 and 6.5㎖/ℓand between 210 and 240cl/t respectively. The most frequent ranges of those values are between 5.5 and 5.7 ㎖/ℓand between 230 and 240cl/t. The northern boundary of the Tsushima Current can be known by the characteristics of the distribuion of dissolved oxygen.