• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.4
• /
• pp.247-258
• /
• 2016

Physical and acoustic properties of sediment on the southwestern Taean Penisula, the Yellow Sea, were studied using eight piston cores. The sediments in the study area are largely composed of sand which has been deposited with sea-level change after LGM(Last Glacial Maximum). After the sea-level rise, fine-grained sediments discharged from Keum River and neighboring coast area were deposited as muddy sand or sandy mud. Results of these sedimentary environment in this area, the texture of sediments are different from place to place with variable horizontal and vertical distribution of physical and acoustic properties. Correlations among the physical, geoacoustic properties, and mean grain size show slight deviations from those of the South Sea in spite of similar pattern. This is probably due to the differences in sedimentary environment, mineral composition, and measurement system.

• Korean Journal of Remote Sensing
• /
• v.20 no.3
• /
• pp.153-162
• /
• 2004

In the summer of 1998-2001, a huge flood occurred in the Yangtze River in the eastern China. Low salinity water less than 28 psu from the river was detected around the southwestern part of the Jeju Island, which is located in the southern part of the Korean Peninsula. We studied how to detect low salinity water from the Yangtze River, that cause a terrible damage to the Korean fisheries. We established a relationships between low salinity at surface, turbid water from the Yangtze River and digital ocean color remotely sensed data of SeaWiFS sensor in the northern East China Sea, in the summer of 1998, 1999, 2000 and 2001. The salinity charts of the northern East China Sea were created by regeneration of the satellite ocean color data using the empirical formula from the relationships between in situ low salinity, in situ measured turbid water with transparency and SeaWiFS ocean color data (normalized water leaving radiance of 490 nm/555 nm).

• Korean Journal of Remote Sensing
• /
• v.22 no.1
• /
• pp.11-24
• /
• 2006

Coastal sea surface temperature (CSST) and meteorological data from January through December 1995 are used to estimate the net surface heat flux and heat content for Sendai Bay. The average annual surface heat flux in the area north of the bay is estimated to be $+35Wm^{-2}$, whereas the southwestern area is estimated to be $+56Wm^{-2}$. Therefore, the net surface heat flux shows a net gain of heat over the whole bay. The largest heat gain occurs near Matsukawaura, where the strong Kuroshio/Oyashio interaction produces anomalously cold SST and wind is more moderate than in other regions of Sendai Bay over most of the year. The lowest heat gain occurs around Tashiro Island, where the temperature difference between air and sea surface is lower and wind is stronger. The heat budget shows that both surface forcing and horizontal advection are potentially important contributors to the seasonal evolution of CSST in the bay. From the A VHRR and SeaWiFS data, it is found that offshore conditions between the bay and Eno Island are different due to the presence of the Ojika Peninsula. It is also shown that the temporal behaviors of SSTs in the bay are closely connected with the air-sea heat flux and offshore conditions.

• Korean Journal of Remote Sensing
• /
• v.33 no.1
• /
• pp.97-109
• /
• 2017

Green tides that developed along the coast of China in 2015 were detected and tracked using vegetation indices from GOCI and Landsat images. Green tides first appeared near the Jiangsu Province on May 14 before increasing in size and number and moving northward to the Shandong Peninsula in mid-June. Typhoon Cham-hom passed through the Yellow Sea on July 12, significantly decreasing the algal population. An algae patch moved east toward Korea and on June 18 and July 4, several masses were found between the southwestern shores of Korea and Jeju Island. The floating masses found in Korean waters were concentrated at the boundary of the open sea and the Jindo cold pool, a phenomenon also observed at the boundary of coastal and offshore waters in China. Sea surface temperatures, derived from NOAA SST data, were found to play a role in generation of the green tides.

• 한국해양학회지
• /
• v.20 no.3
• /
• pp.37-54
• /
• 1985

A description of the "phytohydrography" in the southwestern waters of the East Sea is given from concurrent measurement of temperature, chlorophyll-a, nutrients, and phytoplankton and also from the calculated primary production during the two cruises in May and October, 1984. Past history of water mass is relatively well reflected in the distribution of phytoplankton species, but such a reflection is rarely shown in the distribution of physical and chemical parameters in general. Upper layer of the waters around Ul-gi and Gampo is typically characterized by the high chlorophyll-a, high primary production, and low nanofraction ratio due to the continuing supply of nutrients from the nutrient-rich cold water underneath. Water of Tsushima current shows poor standing crop in terms of cell numbers and chlorophyll-a concentrations, extremely high nanofraction ratio, and very low primary production. The overwhelming importance of the nanofraction is confirmed in phytoplankton cell numbers, chlorophyll-a concentration, and possibly enough in primary production. This emphasizes the exceptionally strong inflow of warm water into the study area from south among all the waters around the whole Korean peninsula.

• Journal of the Korean Geophysical Society
• /
• v.2 no.3
• /
• pp.191-200
• /
• 1999

Analysis of chirp high-resolution seismic profiles from the central Yellow Sea reveals that depositional environments in this area can be divided into three distinctive zones from west to east: (1) subaqueous delta system near the Shandong Peninsula, (2) erosional zone in the central Yellow Sea, and (3) tidal sand ridges and sand waves near the Korean Peninsula. The Shandong subaqueous delta, extending southward from the Shandong Peninsula, changes gradually into prodelta southeastward. The sediments originated from the Yellow River are transported southward along the Chinese coastal area. The erosional zone in the central Yellow Sea contains numerous paleochannels and shows linear erosional features trending northwest-southeast. The erosional zone would be dominated by non-depositional or erosional processes during the Holocene. Tidal sand ridges and sand waves are well developed along the western coast of Korea. The residual sands, which were originally fluvial sediments at the sea-level lowstand, are interpreted as the result of winnowing process during the sea-level rise. Modern sand ridges generally migrates in a northeast-southwestern direction, which coincide with dominant tidal current direction.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.9 no.3
• /
• pp.137-152
• /
• 2004

The climatological characteristics of coastal zone over the southwestern coast of Korea peninsula were investigated using the data observed by AWS (automatic weather system) and 4 buoy points. Coastal zone is climatologically defined as the region bounded by the distinct contrast of temperature gradient and wind speed across coastline. In the southwest of peninsula four cross-lines consisted of AWS aligned with each buoy were selected as Geojedo buoy line, Geomundo buoy line, Chilbaldo buoy line and Dukjukdo buoy line. Analysis on the diurnal cycle and intra-month variation, monthly mean and maximum value, the temperature gradient with distance between buoy and each station and the accumulative frequency of wind speed were applied to find out the characteristics and the range of coast zone. The maximum ranges of coastal zone vary from offshore to Sanglim (about 34 km distance from coastline) for Geojedo buoy line, to Sunchun (about 52 km) for Geo-mundo buoy line, to Jaeundo (about 27 km) for chilbaldo buoy line and to Yongin (about 65 km) for Dukjukdo buoy line. The modification of coastal zone according to synoptic flow was investigated for the onshore, off-shore and calm cases. The ranges of coastal zone are significantly changed with the distance between 65∼90 km for the case of onshore. In addition, we tried to find out the variation of the wind and temperature and the wind ratio of wind speed at ocean to land stations along Geojedo buoy line during 12∼13 Sep. 2003 affected by typhoon (MAEMI).

• Journal of the Korean Geophysical Society
• /
• v.9 no.4
• /
• pp.443-453
• /
• 2006

Using seismic profiles obtained in the Antarctic Peninsula continental margin around Smith Island located at the southwestern end of the South Shetland Islands, we investigated sediments distribution, sedimentation, continental shelf formation, and tectonic evolution history. The study area is a very unique area that has two tectonic provinces with a tectonic boundary near Smith Island just the landward projection of the Hero Fracture Zone (HFZ). To the southwest of the Island, the margin became inactive margin after the collision of the ridge crest of the Antarctic-Phoenix ridge and trench, whereas to the northeast the margin is still apparently active margin with the spreading center and trench morphology in the sea. Generally the northeastern margin has the shelf sedimentary basins wth thick sedimentary layers, well-developed forearc basin, broad continental slope and distinct trench morphology, and the southwestern margin is characterized by steep and narrow continental slope and localized shelf basins. the mid-shelf basement high structures are distinct in the southwestern margin, which are thought to be formed by thermal effect caused by the subducted spreading centers. The high is observed in the area just northeast of the Island, implying that the tectonic boundary along the landward projection of the HFZ is not sharply defined.

• Economic and Environmental Geology
• /
• v.53 no.5
• /
• pp.505-515
• /
• 2020

The Yellow Sea and northern East China Sea contain a transgressive sand layer. Numerous sedimentary studies have been carried out in these sand deposits using seismic exploration and core sediment techniques, but few mineralogical studies have been reported. The major purposes of this study are to describe the distributions of heavy minerals throughout the Yellow sea and northern East China Sea and to identify the provenance of coarse sediments using the mineral chemistry. Eight heavy mineral species were identified in the study area (epidote, amphibole, garnet, zircon, sphene, rutile, apatite, and monazite). The study region was divided into six areas (areas A to F) based on heavy mineral distributions and sampling locations. In mineral chemistry, the amphiboles present are classified as edenite and hornblende in the calcic amphibole group, and the garnets are identified primarily as almandine in the pyralspite group. A combined data set of heavy mineral distributions and mineral chemistry showed clear differentiation of the characteristics of the six classified areas, enabling determination of provenance and sedimentary environment. Area A and B in the eastern Yellow Sea were originated from the Korean peninsula, and these regions showed different heavy mineral characteristics by tidal current and coastal current. In addition, monazite was only found in the area B and could be used as an indicator from the southwestern Korean peninsula. Area D and E in the western Yellow Sea showed the characteristics of sediments originating from the Huanghe, and sediment in the area E was derived from the Changjiang. Area C in the northern East China Sea appeared to have Changjiang-origin sediment, and abundant apatite indicated that area C was formed close to the Last Glacial Maximum.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.45 no.1
• /
• pp.91-101
• /
• 2003

Boryeong Seadike located at southwestern seashore of Korean peninsula completed in 1997. Sluice gate operation can be an important factor to maintain lake water quality and reduce retaining time of pollutants within lake. The lake water quality simulation model, WASPS was adopted and tested to find out proper gate operation timing and discharge amount. From the simulation of sluice gate operation, the results showed that the later the time of discharge for loosing 1 day successively to 6 days, the better the quality of water. Discharge amount showed relatively minor changes of water quality. This means that pollutants flowed into lake from watershed do not have enough time to mix up with deep water when the gate opened at early time. About 3 days delay of discharge caused the dilution effect to stabilize the lake water quality in case of Boryeong freshwater lake.