• Proceedings of the Korean Society of Crop Science Conference
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• 2000.11a
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• pp.3-11
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• 2000

The Asian summer monsoon has a profound social and economic impact in East Asia and its surrounding countries. The monsoon is basically a response of the atmosphere to the differential heating between the land mass of the Asian continent and the adjacent oceans. The atmospheric response, however, is quite complicated due to the interactions between the atmospheric heat sources, land-sea contrast, and topography, The occurrence of extreme summertime floods in Korea, Japan, and China in 1998 and 1999 has highlighted the range of variability of the East Asian summertime monsoon circulation and spurred interest in investigating the cause of such extreme variability. While ENSO is often considered a prime mechanism responsible for the unusual hydrological disasters in East Asia, understanding of the connection between ENSO and the East Asian monsoon is hampered by their dynamic complexities. Along with a recent phenomenon of weather abnormalities observed in many parts of the globe, Korea has seen its share of increased weather abnormalities such as the record-breaking heavy rainfalls due to a series of flash floods in the summers of 1998 and 1999, following devastating Yangtze river floods in China. A clear regime shift is found in the tropospheric mean temperature in the northern hemisphere middle latitudes and the surface temperature over the Asian continent during the summer with a sudden warming since 1977. Either decadal climate variation or climate regime shift in the Asian continent is evident and may have altered the characteristics of the East Asian summer monsoon. Considering the summertime rainfall amount in Korea is overall increased lately, the 1998/99 heavy rainfalls may not be isolated episodes related only to ENSO, but could be a part of long-term climate variation. The record-breaking heavy summer rainfalls in Korea may not be direct impact of ENSO. Instead, the effects of decadal climate variation and ENSO may be coupled to each other and also to the East Asian summer monsoon system, while their individual impacts are difficult to separate.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.268-277
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• 2019

Severe damages will result in human society, when several different critical natural phenomena coincide. One example relates to the resting cysts of Alexandrium species (dinoflagellates that cause paralytic shellfish poisoning), which are preserved in surface sediments throughout Osaka Bay, Japan. These cysts have been found to accumulate particularly densely in shallow areas in the inner parts of Osaka Bay, where a tsunami caused by an earthquake could occur any time. Damage by a tsunami could cause a change of the coastal ecosystems at Osaka Bay including the resuspension of surface sediments containing resting Alexandrium tamarense cysts and the subsequent redistribution of the cysts in newly deposited sediment. Under certain environmental conditions, these cysts could germinate and form dense blooms, leading to paralytic shellfish poisoning. Such a scenario could also affect other coastal areas, including the southern coast of the Korean Peninsula.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.509-522
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• 1996

A total of 460 palaeomagnetic samples was collected from the Tertiary Chongja-Ulsan basins and surrounding area in the southeastern part of Korean peninsula. All samples were stepwise demagnetized by either alternating field or thermal method. It was found that most sample-sites have ChRM declination which has been rotated clockwise from the north-south reference direction of Tertiary East Asia, although other two extrusive sample-sites within the Chongja sedimentary basin show counterclockwise rotation of ChRM declination. Fold tests for the site-mean ChRMs of the latter two sites reveal insignificant result and negative result with 95% confidence level, respectively. The amount of the clockwise deflection of declination varies from about $20^{\circ}$ upto about $80^{\circ}$ according to the block to which each sample-site belongs. The amount of the counterclockwise deflection is about $20^{\circ}$. It is concluded that the clockwise ChRM rotation has been caused by dextral simple shearing accompanied by NNW-SSE spreading of the East Sea which has been active until about 16Ma, and that the counterclockwise rotation is a result of sinistral simple shearing associated with WNW-ESE contraction in the Korean Strait-SW Japan region at about 15 Ma.

• Journal of the Korean earth science society
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• v.38 no.5
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• pp.345-356
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• 2017

It is important to understand the variability of tropospheric ozone since it is both a major pollutant affecting human health and a greenhouse gas influencing global climate. We analyze the characteristics of East Asia tropospheric ozone simulated in a chemistry-climate model. We use a global chemical transport model, driven by the prescribed meteorological fields from an air-sea coupled climate model simulation. Compared with observed data, the ozone simulation shows differences in distribution and concentration levels; in the vicinity of the Korean Peninsula, a large error occurred in summer. Our analysis reveals that this bias is mainly due to the difference in atmospheric circulation, as the anomalous southerly winds lead to the decrease in tropospheric ozone in this region. In addition, observational data have shown that the western North Pacific subtropical high (WNPSH) reduces tropospheric ozone across the southern China/Korean Peninsula/Japan region. In the model, the ozone changes associated with WNPSH are shifted westward relative to the observations. Our findings suggest that the variations in WNPSH should be considered in predicting tropospheric ozone concentrations.

• 한국해양학회지
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• v.27 no.3
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• pp.189-196
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• 1992

A simple quasi-geostrophic model is considered to explain the separation of the East Korean Warm Current(EKWC) and formation of the North Korean Cold Current(NKCC). In this model, the circulation is driven by inflow-outflow condition and modified by local forcing. The solution is decomposed into inflow-outflow and local modes which describe only the effects of inflow-outflow condition and local forcing, respectively. Results of analyses show that both the surface cooling and positive wind stress curl are favorable for the separation of EKWC and formation of NKCC. This fact is compatible with the present knowledge about heat flux and wind stress field over the Sea of Japan.

• 한국해양학회지
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• v.29 no.1
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• pp.64-81
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• 1994

The trend of physical oceanography research in Korea till 1992 is briefly described. Research papers and activities are reviewed and classified according to the research field and geographic area. so this work ca be served as a reference in planning future researches and surveys. Most of the research areas are confined to the nearshore around the Korean Peninsula and the research field do not extend far beyond the classic subjects of physical properties of water masses and tides. etc. Future researches should thus be oriented to the basin-scale circulation aiming at the national oceanographic tasks such as the formation of the Tsushima Warm current, circulation in the Yellow-East china Seas, and three dimensional circulation of the East (Japan) Sea.

• The Korean Journal of Petroleum Geology
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• v.14 no.1
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• pp.63-73
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• 2008

The seismic interpretation was carried out to understand the evolution of the Sora and North Sora Sub-basins, South Sea of Korea. Both sub-basins belong to the Domi Basin, which is located in the northeastern margin of East China Sea Basin with Fukue Basin of Japan. Age assignment of each strata in this study was based on the data of boreholes and seismic interpretation in NW Japan. Four regional horizons were identified, and five geological units; Y(basement), Q(Eocene$\sim$Middle Oligocene), M(Middle Oligocene$\sim$Early Miocene), L(Early Miocene$\sim$Late Miocene) and D(Late Miocene$\sim$Present) groups in ascending order. Structural trends of the main boundary faults and the basin-fill sediment are different between the Sora and North Sora Sub-basins; i.e., trend of the main boundary-faults, dip of horizons, distribution of basin and development of growth fault. These results imply that the Sora Sub-basin would have opened earlier than the North Sora Sub-basin.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.2
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• pp.83-90
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• 1984

The secular fluctuations of catches and fishing grounds of mackerals and the oceanographic conditions for the fishing grounds are examined by using the data of catches of mackerals by middle and large class purse-seiner during 1951 to 1981 and those of oceanographic observation carried out by Japan Meteorological Agency. The results are as follows; The fishing grounds of mackerals are respectively distributed at northeastern and southwestern areas from the central part of the East China Sea through every season of the studied years: 1968, 1974 and 1980. The narrow belt type of fishing grounds were formed inside of the Kuroshio in spring and winter of the three years. In summer mackeral species move northward and the fishing grounds are formed in the southern sea of Korea. In winter, however, mackeral species move southward and the fishing grounds are appeared in the Tsushima Current region. The dispersion of fishing grounds is generally larger in summer and smaller in spring, and especially it is the largest in summer in 1980. It seems that the concentration and dispersion of fishing grounds are related to the depth of thermocline and the position of horizontal temperature gradient in this area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.749-759
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• 1998

Distribution of zooplankton abundance was studied in the front zone in the East Sea in November, 1996, Averaged total abundance in the front zone was less than that in the nearby cold surface water areas but more than that in the nearby warm surface water areas. The number of taxa was the greatest in the upper layer of mixing. Abundance and the number of tun in the front zone were contributed by the cold water and the warm water, respectively. Inspite of the differences in sampling time (day vs night), the species composition and abundance distribution were similar at two sites within cold or warm water area, However, they were quite different at two sites in the front zone although the sampling time of the day was the same. from this, the history of mixing was believed to be the most important factor for the species composition and abundance distribution in the front zone. Zooplankton distribution in the study area was mainly controlled by the dominant cold water Copepod Species Metridia paoifica, the only taxon that showed significant diet vertical migration. Most other taxa showed no significant diel vortical migration, Seawater temperature also affected zooplankton distribution. Positive correlations in the warm area, weak negative correlations in the cold water area, and no significant correlation in the front zone were obtained in general between the seawater temperature and the abundances of the major taxa.

• Journal of Contemporary Eastern Asia
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• v.11 no.2
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• pp.47-60
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• 2012

Sino-Japanese relations suffered a great setback during the premiership of Koizumi $Jun'ichir{\bar{o}}$ (2001-2006). Although many factors, such as dispute over the resources of the East China Sea or Japan's anxiety about China's growing military expenditures, are accountable for this situation, it was Koizumi's visits to the Yasukuni Shrine that became a symbol of the controversies between the two countries. The Yasukuni issue triggered a real eruption of profound anti-Japanese feelings among the Chinese people. While commentators in China accused Koizumi of glorifying militarism and whitewashing the atrocities committed by Japanese soldiers during the Second World War, the Japanese public started perceiving China's "exaggerated" reaction as a convenient diplomatic tool used by China to apply pressure on Japan in other bilateral disputes. On the one hand, spontaneous protests against Koizumi's visits to the Yasukuni Shrine constituted a great constraint in China's diplomacy towards Japan, but on the other, they also became an ideal pretext for adopting a tougher stance in Chinese foreign policy. In this paper, I examine different points of view on the Yasukuni issue. After describing the Japanese background of the visits to the controversial shrine, I analyze various interpretations of China's reaction to the problem. Although emotions dominated discourse on the Yasukuni issue both in Japan and China, some pragmatic attempts to use this problem can still be seen. Besides being a side-effect of Koizumi's strong personality, the Yasukuni issue could be used either as a tool of factional struggle in the Chinese Communist Party (CCP) or as an instrument of Chinese foreign policy towards Japan.