• Korean Journal of Remote Sensing
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• v.32 no.6
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• pp.703-719
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• 2016

We investigated the changes with temporal and spatial movements of cold water events in summer season around the East Sea of Korea. Several data analyses were performed based on the various environmental factors using satellite and in-situ (winds, air/sea surface temperatures) data in the summer season during 2013. For analyzing the influence of cold water life cycle we employed AVISO geostrophic current and daily Geostationary Ocean Color Imager (GOCI) chlorophyll concentration (chl) data. Also, we used daily Advanced Very High Resolution Radiometer-Sea Surface Temperature (AVHRR-SST) data to trace the movements of cold water events. We found out the cold water events occurred in the early summer season and disappeared in the late summer season, and the cold water life cycle is repeated in this period. Additionally, we could show that the chl were increased in late summer season due to the inertial influence of cold water zone.

• Ocean and Polar Research
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• v.36 no.1
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• pp.59-69
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• 2014

The long-term mooring performed at a KOGA station, located at about $30^{\circ}20^{\prime}N$, $126^{\circ}12^{\prime}E$ in the East China Sea shelf, shows some different behaviors between "semi-diurnal" and "diurnal currents" defined as the currents with periods around, respectively, a half day and a day. They appear to be predominantly tidal having significant coherences with sea level changes around the semi-diurnal and diurnal frequencies. The "semi-diurnal current" is strongly barotropic all year round. However, contrastingly, it is largely baroclinic in summer in the area about 70 km nearer to the continental slope, referred to as the "slope-area", as was found in previous current observations. The "diurnal current" of tidal origin is strongly barotropic in winter. In spring and summer, however, it becomes more baroclinic although it still remains largely barotropic, also showing more of its barotropic nature than in the "slope-area". The inertial oscillation contributing to the "diurnal current" appears to be more prominent when the current is baroclinic, indicating the important role played by stratification in generation of inertial oscillations. Downward energy propagation of inertial oscillation is not observed, suggesting that it is not created at the surface by wind. Considering that the study area is both near a critical latitude and proximity to the continental slope, it is suggested that parametric subharmonic instability (PSI) plays a significant role in creating the baroclinic inertial oscillation.

• 한국해양학회지
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• v.18 no.1
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• pp.1-9
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• 1983

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.

• 한국해양학회지
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• v.9 no.2
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• pp.10-18
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• 1974

The cold water mass around the southeast coast of the Korean Peninsula is analyzed by using CSK data from 1966 through 1970. It is shown that this water mass flows down from the region offshore of Jukbyun to the area of Youngil Bay along the 100meter contour line of bottom topography. In ordinary summer conditions when the current velocity in the Korea Strait is usually above about 50cm/sec and the wind direction is southwest, the cold water ascends to the surface and makes the surface temperature gradient large, unless disturbed by a tropical cyclon. The bottom water of the Korea Strait is formed by the stratification after the Tsushima intermediate water and the Japan Sea intermediate water have been mixed. In winter the Tsushima intermediate water with high salinity sinks rapidly around the inlet of the Japan Sea and prevents the Japan Sea intemediate water from entering the Korea Strait.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.26 no.2
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• pp.151-166
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• 1990

Using the data observed on the Oshoro-maru from November 4 to November 12, 1989 in the East China Sea, the oceanographic conditions were investigated. The results are as follows: The oceanographic condition of surface layer was divided into two regions. One was the Tsushima Current Waters and the other was the China Coastal Waters. The oceanic front was formed between above two waters. Tsushima Current Waters had high temperature ranging 22~24$^{\circ}C$, high salinity ranging 33.5~34.5$\textperthousand$ and low D.O less than 4.5ml/l. And China Coastal Waters had low temperature ranging 18~2$0^{\circ}C$, low salinity less than 23.0$\textperthousand$ and high D.O ranging 4.0~5.0ml/l. In the case of the bottom layer, Tsushima Current Waters and China Coastal Waters appeared the same as the surface layer. In addition, the Yellow Sea Bottom Cold Waters and the Southern Bottom Waters of East China Sea distributed together with two surface waters above. The was temperature ranging 15~19$^{\circ}C$, salinity 34.5$\textperthousand$ and low D.O ranging 2.0~3.5ml/l and that was temperature less than 1$0^{\circ}C$, salinity less than 33.3$\textperthousand$ and high D,O greater than 4.5ml/l. The waters of intermediate characteristics between China Coastal Waters and Tsushima Current Waters seem to be resulted from the mixing occurred between the above tow waters, and it had temperature of 20.5~22.$0^{\circ}C$, salinity of 32.3~33.3$\textperthousand$.

• Fisheries and Aquatic Sciences
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• v.1 no.2
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• pp.276-282
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• 1998

As a part of the long-term ADCP mooring program to measure the mass flux through the Korea Strait, current velocity data were obtained for 39 days in the deepest point of the strait. Near-surface velocity of this observation was compared with Izuhara-Pusan sea level difference (SLD) to investigate the geostrophic relationship. Principal direction of the Tsushima Current at the mooring station is 44.6 degrees to the north from the east. Variability of the tidal current is greater than the nontidal current by a factor of two. Correlation coefficient of tidal current against SLD is 0.46 but the nontidal current is not correlated. The current velocity (U in cm/s) can be estimated from the demeaned SLD (in cm) by the relation U=23.63+0.64SLD where the maximum range of SLD is 52.9 cm. Current is coherent with SLD at semidiurnal, diurnal and 42.7-hour periods. A dominant nontidal variability with about 5-day period is not coherent with SLD.

• 한국해양학회지
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• v.6 no.2
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• pp.99-103
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• 1971

GEK observation had been done in Satsunan sea region (south western region of Kyushu, Japan), mixing sea region of Kuroshio, its count-current and water mass of Eastern China Sea in August 1968. The results are al follows: 1. Observed values by GEK are coincided well with that of ship's drift in the surface water of Kuroshio region. 2. Compared the observed values by GEK with that of dynamic calculation of 800 db, in the eastern area of the surveyed region occupied by Kuroshio water mass, they are coincided well. But not in the western area which is of mixing zone of the Eastern China Sea water mass, Kuroshio and its count-current, showing over 1 knot differences with calculated value are bigger than that of GEK observation.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.149-154
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• 2010

The feasibility of lead removal by electrolytic coprecipitation was investigated. Electrolysis bath was divided into anode and cathode chamber with anion exchange resin filled membrane. Sea water was electrolyzed and pH of the electrolyte in cathode chamber was increased. Consequently it induced the formation of $Mg(OH)_2$ and $CaCO_3$. The colloidal type precipitates, hich have high surface area, adsorbed lead ions in sea water and coprecipitated. Sea water electrolyses were conducted at different current density. Concentrations of Mg, Ca and Pb in the solution were measured with titration and ASV method. Morphology and crystallography were analyzed with SEM, EDS and XRD. As pH and current density increased, most of lead ions in the sea water were successfully removed.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.18 no.2
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• pp.91-96
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• 1982

Temperature inversions are investigated by using the oceanographic data obtained in the Yellow Sea from 1965 to 1979. The temperature inversions are found in every depth in almost all areas of the Yellow Sea. While in summer, they frequently occur below thermocline in the west region of the Jeju Island. Such phenomena in winter can be explained by surface cooling effects associated with a net heat loss at the surface and a southward advection of cold water, and those in summer result from the process of mixing between the Yellow Sea Warm Current and the Yellow Sea Bottom Cold Water.

• Journal of the korean society of oceanography
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• v.38 no.3
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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.