• 한국해양학회지
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• v.7 no.2
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• pp.86-97
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• 1972

The tides, tidal currents and tidal prisms at Inchon Harbor are studied with recent data. The tides at Inchon Harbor is of semi-diurnal type having a spring range of 798cm and a phase age of 2 days. The monthly mean sea level at Inchon has a maximum at August and a minimum at January with a annual range of about 40cm. the tidal currents at Inchon Outer Harbor are of semi-diurnal type same as tides and nearly reversing type. The flood and ebb currents set north and south with a velocity of about 90-175 cm/sec and 120-225 cm/sec at spring tide and begin 0.2 hours after L.W. and 0.7 hours after H. W., respectively. Non-tidal currents flow southward with 10-20 cm/sec at west side of the stream and northward with 15-20 cm/sec at east side of the stream at Inchon Outer Harbor. The flood volume through the Inchon Outer Harbor fluctuates fortnightly from 590 10$\^$6/㎥ spring tide to 260 $10^6/m^3$ at neap tide and ebb volume changes from 470 $10^6/m^3$ at spring tide to 200 $10^6/m^3$ at neap tide, respectively. The flow area along the channel to the Estuary of Yeomha is controlled by the tidal prism as expressed by $A=1.14{\times}10^{-4}P^{0.966}$

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.267-271
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• 2017

Diel changes in feeding activity of juvenile Pacific herring, Clupea pallasii were investigated throughout the analysis of stomach contents of 301 fishes collected from the southeastern coast of Korea. Fish samples were collected every 3 hour over a 24 h period in summer using small bottom trawl. The ratio of empty stomach, stomach fullness, stomach contents index (SCI) and stomach fullness index (IF) of juvenile C. pallasii were varied markedly with day/night changes. The ratio of empty stomach tended be higher during nighttime, while the other values were higher at daytime, with showing peak before sunset. During daytime, the stomach contents mainly were made up of copepods and euphausiids, while the diets at midnight were composed of nearly digested and unidentifiable items.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.259-264
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• 2001

Typhoon and neap tide on Cochlodinium polykrikoides bloom and water temperature on disappearance of C. polykrikoides bloom were investigated to elucidate the outbreak mechanism of C. polykrikoides blooms at Naro and Namhae coastal area in South Sea of Korea. The first observation of C. polykrikoides blooms were observed when thermocline was disappeared by typhoon, tide, etc. The first blooms of C. polykrikoides were observed on neap tide or before one day from neap tide in 1996-1998 and 2000. However, thermocline was disappeared by typhoon in 1994 and 1999, the first blooms were observed early 12-30 day than 1996-1998 and 2000. The main reason of disappearance of C. polykrikoides blooms after typhoon on 1997-2000 seems to be other environmental change by typhoon rather than low water temperature. In the future, the first C. polykrikoides bloom will be appear around the first neap tide of latter part of August with breaking down of thermocline, but if the thermocline be collapsed by typhoon in July, the C. polykrikoides bloom will be appear at beginning of August. The outbreak of C. polykrikoides blooms will be explain as follows: The vegetative cells, which was germinated by environmental change or already exist in surface water at low level, input to the surface water, and then nutrients and trace metals which were suppled from out side of C. polykrikoides bloom area inflow to surface. The vegetative cells are growth by the nutrients and trace metals at suitable environmental conditions e.g. water temperature, salinity, and sufficient light.

• 한국해양학회지
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• v.30 no.3
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• pp.170-183
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• 1995

Eddies and surface current field in the southwestern part of the East Sea were investigated using satellite-tracked drifters, CTD, and ADCP from November 1992 to September 1993. Trajectories of surface drifters provided information for the first time on the meandering motion of the East Korean Warm Current in the Ullung Basin (referred as UB) and clearly indicated the existence of cyclonic and anticyclonic eddies of various scales. Anticyclonic eddies persisting for a relatively long period were observed in UB and the southwestern corner of the Northern (Japan) Basin (SNB), while a cyclonic eddy was found in the coastal area between Sokcho and Donghae during the summer. Analysis shows that the eddy in UB behaved as a stationary eddy at least during the observation period and the cyclonic eddy was closely related to the existence of a cold water mass. The anticyclonic eddy in SNB was larger than that in UB, but much elongated in shape. The eddy in UB is characteristic of major and minor axes of about 120 and 70 km, revolution period of 13.6 days, mean swirl velocity of about 24 cm/s, and mean eddy kinetic energy of 392 cm$\^$2//s$\^$2/. The eddy in SNB is described as follows; major and minor axes of 168 and 86 km, period of 14.9 days, mean swirl velocity of 29 cm/s and mean eddy kinetic energy of 629 cm$\^$2//s$\^$2/. The mean translational speed is about 3 cm/s for both eddies. The agreement of the surface current pattern in UB observed by ADCP with the geostrophic flow pattern may suggest that the eddy in UB was nearly in geostrophic balance. The eddy was found to be strongly bottom-controlled.

• Atmosphere
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• v.26 no.4
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• pp.617-633
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• 2016

Jangbogo station is located in Terra Nova Bay over the East Antarctica, which is often affected by individual storms moving along nearby storm tracks and a katabatic flow from the continental interior towards the coast. A numerical simulation for two strong wind events of maximum instantaneous wind speed ($41.17m\;s^{-1}$) and daily mean wind speed ($23.92m\;s^{-1}$) at Jangbogo station are conducted using the polar-optimized version of Weather Research and Forecasting model (Polar WRF). Verifying model results from 3 km grid resolution simulation against AWS observation at Jangbogo station, the case of maximum instantaneous wind speed is relatively simulated well with high skill in wind with a bias of $-3.3m\;s^{-1}$ and standard deviation of $5.4m\;s^{-1}$. The case of maximum daily mean wind speed showed comparatively lower accuracy for the simulation of wind speed with a bias of -7.0 m/s and standard deviation of $8.6m\;s^{-1}$. From the analysis, it is revealed that the each case has different origins for strong wind. The highest maximum instantaneous wind case is caused by the approach of the strong synoptic low pressure system moving toward Terra Nova Bay from North and the other daily wind maximum speed case is mainly caused by the katabatic flow from the interiors of Terra Nova Bay towards the coast. Our evaluation suggests that the Polar WRF can be used as a useful dynamic downscaling tool for the simulation and investigation of high wind events at Jangbogo station. However, additional efforts in utilizing the high resolution terrain is required to reduce the simulation error of high wind mainly caused by katabatic flow, which is received a lot of influence of the surrounding terrain.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.4
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• pp.215-228
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• 1991

In the East Sea of Korea the vertical structure functions of the temperature field were evaluated and the characteristic thermal zone was classified by the use of the empirical orthogonal function(EOF) method. The East Sea of Korea within the hydrographic lines of 10-107 of the Fisheries Research and Development Agency of Korea(FRDA) can be divided into three thermal regions by the characteristics of the vertical temperature variability. They are the North Korean Cold Current(NKCC) region near the coast which extends parallel to the north-south direction, the Warm-Core(WC) region which dominates almost all the hydrographic stations of the Line 104 of the FRDA and occupies a few stations of the Line-103 and -105 with its axis at the Line 104, and the East Korea Warm Current(EKWC) region which is bisected into the northern and the southern part by the WC region, respectively. Considering the two most important modes, $85.20-98.20\%$ of the total variance of temperature variation are explained in the NKCC region, $85.20-92.90\%$ in the EKWC region, and$85.50-91.70\%$ in the WC region. The first mode has its peak value at the surface with the annual cycle of variation. The spatial pattern of the first mode portrays a coherent vertical variation in the EKWC region and a clear anti-correlation both in the NKCC region and in the WC region where the zero-crossing depths are loom and 200m, respectively. The second mode of the NKCC region is particularly noticeable, haying its peak at loom with coherent vertical variation. To study the time dependency of the vertical structure functions, the extended EOF(EEOF) method was used. The persistence of the first mode is less than 4 months in the study area. The annual variation of the first mode in the NKCC region is different from those in the WC region and in the EKWC region.

• 한국해양학회지
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• v.30 no.6
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• pp.550-564
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• 1995

The temporal and spatial characteristics of wind fields over the neighbouring seas of the Korean peninsula are investigated using 10-years daily wind data during 1978${\sim}$1987 which have been spatially smoothed and low-pass filtered. Long term annual and monthly means are examined for synoptic patterns and spectral analyses are made for temporal variability and spatial coherence. Spatial patterns of the annual mean wind stress and curl have a strong resemblance with those of monthly means during the winter season. Two outstanding periodicities are observed at 1 and 2 cycles per year. The synoptic winds over the study area are highly coherent at both the annual and semi-annual periodicities. However, each basin has its own characteristic spatial pattern. For instance, the prevailing wind during the winter season is northerIy over the northern East Sea (ES), Yellow Sea (YS), and northern East China Sea (ECS), while it is northwesterly over the southern ES and northesterly over the northern ES and southern ECS. At the same time, the wind stress curl is positive over the northern ES and southern ECS, while it is negative over the southern ES, YS and northern ECS. On the other hand, the wind field during the summer season, with its strength being much reduced, is completely different from that during the winter season, and frequent passage of tropical storms provokes large temporal variability over ECS. One remarkable point is that the annual cycle, dominated by the Siberian High, tends to propagate from northeast to southwest, i.e., from northern 25 toward southern ES, YS and ECS, while the semi-annual cycle propagates in the opposite direction, from southwest to northeast. The semi-annual periodicity may reflect development of extratropical cyclones in spring and fall which frequently cross the Korean peninsula. In higher frequencies, there are no dominant periodicities, but local winds over YS and ES are highly correlated for frequencies larger than 0.1 cycles per day and phase difference increases linearly with frequency. This linear increase of phase corresponds to phase speed of 550 and 730 km/d at 0.1 and 0.3 cpd, respectively, The phase speed is apparently coincident with moving speed of extratropical cyclones across the Korean peninsula in the west-east direction.

• 한국해양학회지
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• v.23 no.3
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• pp.123-129
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• 1988

The toxicity of bivalves in the Korean waters was investigated during 1987-1988. The toxicity of paralytic shellfish poison (PSP) was found in the sea mussels (Mytilus edulis galloprovincialis, M. corsucus), scallops (Patinopecten yessoensis, Chlamys farreri), tellin (Peronidia venulosa) and venus clam (Ruditapes philippinarum) among the 28 species screened. The toxicity in mussels, scallop (C. farreri) and venus clam was mainly confirmed from the samples collected around Jindong Bay in the southern coast of the peninsula, whereas the toxicities of tellin and scallop (P. yessoensis) were found in the vicinity of Pohang in the east coast. Samples from the west coast showed low levels of toxicity than those from the east arid south coasts. Although it varied with the regions, the toxicity was detected mainly during April to June, exceptionally during May to August in Pohang. The levels of toxicity were generally below the criteria of 4 mouse unit (MU)/g edible portion in foreign countries, with few exceptions.

• 한국해양학회지
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• v.1
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• pp.25-36
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• 1971

The structure of the south Korean coastal front, their fluctuation, the properties and the probable effects of the front on the mackerel fishery are discussed based on the data of 26 cruises in 1967-1969 in the southern waters of Korea. In the south Korean coastal water the annual variations of the properties shows the greatest magnitude among the other water masses in the north of East China Sea. The salinity profile provides a fairly accurate description of the interface between the two kinds of water and agree with the temperature structure in winter. The temperature front does not always coincide with the salinity front in summer, while the former corresponds to the later in winter. The sharpest and most stable front between the Tsushima Warm Current and the south Koren coastal water was found in autumn and winter. In autumn 1969, the most successful catches of mackerel was recorded in the south Korean front of great borizontal gradients of properties(temperature 5.0$^{\circ}C$/10miles, salinity 1.2 /10miles) in the east of Cheju Is. If future investigation finds the peculiar oceanographical conditions like that shown in summer, 1969, the conditions of frontal layer in coming autumn will be estimated and finally the success of the mackerel fishery will be predictable from preseason information on temperature and salinity structure in the southern waters of Korea.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.873-880
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• 2009

A novel xylanase gene, Kxyn, was cloned from Kocuria sp. Mn22, a bacteria isolated from the deep sea of the east Pacific. Kxyn consists of 1,170 bp and encodes a protein of 390 amino acids that shows the highest identity (63%) with a xylanase from Thermohifida fusca YX. The mature protein with a molecular mass of approximately 40 kDa was expressed in Escherichia coli BL21 (DE3). The recombinant Kxyn displayed its maximum activity at $55^{\circ}C$ and at pH 8.5. The $K_m,\;V_{max}$, and $k_{cat}$ values of Kxyn for birchwood xylan were 5.4 mg/ml, $272{\mu}mol/min{\cdot}mg$, and 185.1/s, respectively. Kxyn hydrolyzed birchwood xylan to produce xylobiose and xylotriose as the predominant products. The activity of Kxyn was not affected by $Ca^{2+},\;Mg^{2+},\;Na^+,\;K^+$, ${\beta}$-mercaptoethanol, DTT, or SDS, but was strongly inhibited by $Hg^{2+},\;Cu^{2+},Zn^{2+}$, and $Pb^{2+}$. It was stable over a wide pH range, retaining more than 80% activity after overnight incubation at pH 7.5-12. Kxyn is a cellulase-free xylanase. Therefore, these properties make it a candidate for various industrial applications.