• 한국해양학회지
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• v.27 no.4
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• pp.324-331
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• 1992

Water masses and circulations around Korean peninsula are briefly described based on recent studies. The results of theses studies are discussed from the physical point of view. Oceanic conditions in this region are largely due to the roles played by the Tsushima Warm Current, an onshore extension of the Kuroshio, and local conditions such as wind, surface heat flux and fresh water input etc. To the south and west of Korea, the northern/western border of the Tsushima Warm Current Water is roughly the line joining Taiwan and Cheju island. In summer, it is affected by large amount of fresh water discharged from the Changjiang and in winter, an intrusion of this water into the Yellow Sea is induced by the prevailing northwesterly monsoon wind. To the east of Korea, the Tsushima Warm Current Water presents roughly south of the line joining the wast coast of Korea near 37-38$^{\circ}$N and Tsugaru-Soya Straits in the northern Japan. But this situation, together with those in deeper layers, may greatly be changed by winter atmospheric conditions (wind and surface heat flux). The seas around Korea are not yet physically well understood and many problems wait physical explanations. Some problems, along with personal views of them, are mentioned.

• Atmosphere
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• v.26 no.1
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• pp.159-183
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• 2016

On 31 July 2014, there was a localized torrential rainfall ($58.5mm\;hr^{-1}$) caused by a strong convective cell with thunder showers over Daegwallyeong. In the surface synoptic chart, a typhoon was positioned in the East China Sea and the subtropical high was expanded to the Korean peninsula. A WRF (Weather Research and Forecasting) numerical simulation with a resolution of 1 km was performed for a detailed analysis. The simulation result showed a similar pattern in a reflectivity distribution particularly over the Gangwon-do region, compared with the radar reflectivity. According to the results of the WRF simulation, the process and mechanism of the localized heavy rainfall over Daegwallyeong are as follows: (1) a convective instability over the middle part of the Korean peninsula was enhanced due to the low level advection of warm and humid air from the North Pacific high. (2) There was easterly flow from the coast to the mountainous regions around Daegwallyeong, which was generated by the differential heating of the insolation among Daegwallyeong and the Yeongdong coastal plain, and nearby coastal waters. (3) In addition, westerly flow from the western part of Daegwallyeong caused a strong convergence in this region, generating a strong upward motion combined by an orographic effect. (4) This brought about a new convective cell over Daegwallyeong. And this cell was more developed by the outflow from another thunderstorm cell to the south, and finally these two cells were merged to develop as a strong convective cell with thunder showers, leading to the record breaking maximum rainfall per hour ($58.5mm\;hr^{-1}$) in July.

• Korean Journal of Remote Sensing
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• v.17 no.2
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• pp.131-139
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• 2001

Extraction of waterline in tidal flat has been one of the main concerns in the remote sensing of coastal region. This study aimed to define the spectral characteristics of turbid water near the shoreline and to find the appropriate spectrum to delineate the waterline at the inter-tidal flat in the western coast of Korean Peninsula. Spectral reflectance curves were obtained by the field measurements under the diverse condition of water depth and turbidity at the study area in Kyong-gi Bay. Spectroscopy measurements showed that reflectances of the exposed mudflat, shallow turbid water, and normal coastal water were significantly different by wavelength. Shallow water near the waterline showed diverse conditions of turbidity. Spectral reflectance tends to increase as turbidity increases, particularly at the visible and near infrared spectrum. At the middle infrared wavelength, tidal water showed very little reflectance regardless of the turbidity and water depth and was easily disting from the exposed tidal flat. The exact waterline between exposed tidal flat and seawater should be extracted from the image data obtained at the middle infrared wavelength.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.1
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• pp.19-30
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• 2017

The altitudinal potential source contribution function (PSCFa) method was developed by considering topography and height of back trajectories. The PSCFa calculated on the contributions of trans-boundary transport to the hourly mean concentrations of aerosol optical depth (AOD) of the Aerosol Robotic Network (AERONET) in the Distributed Regional Aerosol Gridded Observation Networks (DRAGON) KORea-US Air Quality (KORUS-AQ) campaign from March 31 to July 1 in 2016. Eastern China ($33^{\circ}N{\sim}35^{\circ}N$ and $119^{\circ}E{\sim}121^{\circ}E$) can be the major source of trans-boundary pollution to the western area in South Korea resulted from PSCFa (0~700 m). In this study, AOD by Moderate Resolution Imaging Spectroradiometer (MODIS) was compared to verify the source regions. Regionally, the effects of the long-range transport of pollutants from the eastern China on air quality in south Korea have become more significant over this period.

• Parasites, Hosts and Diseases
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• v.58 no.1
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• pp.81-86
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• 2020

Trematode specimens were collected from the intestine of a herring gull, Larus argentatus, which was found in a critical condition on the shore of a small island (Yubu-do, Seocheon-gun, Chungcheongnam-do) located at the western coast of the Korean peninsula. Total 11 specimens of intestinal flukes, including 3 Cryptocotyle lingua (Heterophyidae), 1 Himasthla alincia (Echinostomatidae), 5 Cardiocephaloides medioconiger (Strigeidae), and 2 Diplostomum spathaceum (Diplostomidae), were recovered. C. lingua was morphologically characterized by the presence of a large ventrogenital apparatus and 2 obliquely tandem testes. H. alincia had an elongated body and a head collar equipped with 31 collar spines. C. medioconiger had a bisegmented body and a voluminous copulatory bursa containing the seminal vesicle and ejaculatory duct. D. spathaceum also had a bisegmented body and its vitellaria extended up to the anterior border of the tribocytic organ. It is of note that C. lingua is potentially zoonotic that can occur in birds and humans. Three of them, i.e., C. lingua, C. medioconiger, and D. spathaceum, are new trematode fauna in Korea. Studies on trematode fauna of migratory birds should be continued in Korea.

• Journal of Ecology and Environment
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• v.44 no.4
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• pp.212-221
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• 2020

Background: Rapid industrialization has caused various impacts on nature, including heavy metal pollution. However, the impacts of industrialization vary depending on the types of industrializing activity and surrounding environment. South Korea is a proper region because the rapid socio-economical changes have been occurred since the late nineteenth century. Therefore, in this study, we estimate the anthropogenic impacts on an ecosystem from a sediment core of Yonghwasil-mot, an irrigation reservoir on the western coast of Korea, in terms of heavy metal concentrations, nutrient influx, and pollen composition. Results: The sediment accumulation rate (SAR) determined by 210Pb geochronology showed two abrupt peaks in the 1930s and 1950s, presumably because of smelting activity and the Korean War, respectively. The following gradual increase in SAR may reflect the urbanization of recent decades. The average concentrations of arsenic (As), copper (Cu), and lead (Pb) during the twentieth century were > 48% compared to those before the nineteenth century, supporting the influence of smelting activity. However, at the beginning of the twenty-first century, the As, Cu, and Pb concentrations decreased by 19% compared to levels in the twentieth century, which is coincident with the closure of the smelter in 1989 and government policy banning leaded gasoline since 1993. The pollen assemblage and nutrient input records exhibit changes in vegetation cover and water level of the reservoir corresponding to anthropogenic deforestation and reforestation, as well as to land-use alteration. Conclusions: Our results show that the rapid socio-economic development since the twentieth century clearly affected the vegetation cover, land use, and metal pollutions.

• Maritime Security
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• v.1 no.1
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• pp.149-173
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• 2020

While the United States and other Western states are in trouble with COVID-19 crisis, China is continuing its aggressive ocean expansion with its Gray-zone strategy. The Gray-zone strategy, which China uses around the South China Sea, refers to a strategy that promotes a change in international politics by creating an unclear state, neither war or peace. China, which is trying to expand its influence across East Asia, will also try to project a Gray zone strategy on the Korean Peninsula. The possible scenarios are as follows: 1) South Korea is accidentally involved in a dispute in the South China Sea, 2) Military conflicts between South Korea and China is caused by illegal fishing of Chinese boats in Yellow Sea, 3) China tries to interfere with Socotra Rock, 4) Unlikely, but possible in the future that China induce the military conflicts between Korea and Japan on the Dokdo issue. In order to cope with these scenarios, Korea should prepare the following measures from a long-term perspective: the creation of an Asian maritime safety fleet, the integ rated operation of the navy and the coast guard in the framework of the national fleet, and strengthening the conflict control system for China's provocations.

• Journal of the Korean association of regional geographers
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• v.6 no.2
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• pp.57-69
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• 2000

The purpose of this study is to identify distributional characteristics of autumn droughts in occurrence frequency and to analyze synoptic characteristics on the surface pressure fields and 500hPa levels for autumn droughts in Korea. The regional distributions of autumn droughts in occurrence frequency vary according to the monthly regional distributions of the precipitation variabilities in Korea. In september, the southwestern and the mid western parts of Korean Peninsula have high rate of drought frequency, while the eastern coast regions have low rate of it. It means that the regional distribution of the drought frequency in september indicates west-high and east-low pattern. In October, the regional distribution of the drought frequency shows low variations on regions, but in November the inland areas have low rate of drought frequency, whereas the coastal areas have high rate of it. Negative anomalies appear on the surface and 500hPa level, around Korean Peninsula during the drought period of early autumn. Positive height anomalies areas are extended from the Sea of Okhotsk to the central part of the North Pacific Ocean. It indicates that the occurrence frequencies of blocking high and ridge are high around the Sea of Okhotsk. When the pressure system, such as migratory anticyclone, stays around the Korean Peninsula, a drought occurs. In late autumn drought, the positive anomalies appear in the west and the negative anomalies in the east are generated, respectively and therefore, zonal wind is strong around Korean Peninsula. In consequence, occurrences of droughts in early autumn have a different mechanism from those of late autumn.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.149-162
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• 2019

In the macro-tide open coast of the Korean western coast, typhoon effects were investigated in terms of variations on topography, surface sediment, and sedimentary environment, which appeared before and after the typhoon Kompasu of 2010. The Kompasu of small size and strong intensity landed on the southwestern coast of the Korean Peninsula and passed across the inland between September 1st and 2nd in 2010. Topography and surface sediments before and after the typhoon were measured and sampled along the survey line of 22 sites in the Gochang Donghori intertidal flat. The intertidal area was divided into high tidal zone, middle tidal zone, and lower tidal zone on the basis of mean high water level, mean sea level, and mean low water level. Topographic variation before and after the typhoon represented deposition of average 0.03 m in high tidal zone, erosion of average -0.15 m in middle tidal zone, and erosion of average -0.39 m in lower tidal zone, respectively. Surface sediments of the intertidal flat consisted mainly of fine to medium sands, and the ratio of fine sand was the largest both before and after the typhoon. Surface sediments after the typhoon became finer in mean grain size showing well sorting rather than those before the typhoon.

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.5-20
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• 2002

To investigate the effect of mechanical parameters on the circulation and its fluctuation in Sagami Bay, baroclinic model experiments were carried out by use of a two-layer source-sink flow in a rotating tank. In the experiment, a simple coastal topography with flat bottom was reproduced. The results show that the path of the Through Flow, which corresponds to the branch current of the Kuroshio, depends on external Rossby number (Ro) and internal Rossby number $(Ro^*)$, and divided into two regimes. For $Ro^*\leq1.0$ in which Rossby internal radius of deformation of the Through Flow is smaller than the width of the approaching channel, the current flows along the Oshima Island as a coastal boundary density current separated from the western boundary of the channel. For $Ro^*>1.0$ it changes to a jet flow along the western boundary of the channel, separated from the coast of Oshima Island. The current is independent on both Ro and Ro* in the regime of $Ro^*>1.0,\;Ro\geq0.06$ and $Ro^*\leq1.0,\;Ro\geq0.06$. The pattern of the cyclonic circulation in the inner part of the bay is also determined by Ro and Ro*. In case of $Ro^*\leq1.0$, frontal eddies are formed in the northern boundary of the Through Flow. These frontal eddies intrude into the inner part along the eastern boundary of the bay providing vorticity to form and maintain the inner cyclonic circulation. For $Ro^*>1.0$, the wakes from the Izu peninsula are superposed intensifying the cyclonic circulation. The pattern of the cyclonic circulation is divided into three types; 1) weak cyclonic circulation and the inner anticyclonic circulation $(Ro<0.12)$. 2) cyclonic circulation in the bay $(0.12\leq Ro<0.25)$. 3) cyclonic circulation with strong boundary current $(RO\geq0.25)$.