• Atmosphere
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• v.25 no.4
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• pp.611-622
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• 2015

Heavy rainfall ($>30mm\;hr^{-1}$) over the Korean Peninsula is examined in order to understand thermo-dynamic characteristics of the atmosphere, using radiosonde observational data from seven upper-air observation stations during the last 17 years (1997~2013). A total of 82 heavy rainfall cases during the summer season (June-August) were selected for this study. The average values of thermo-dynamic indices of heavy rainfall events are Total Precipitable Water (TPW) = 60 mm, Convective Available Potential Energy (CAPE) = $850J\;kg^{-1}$, Convective Inhibition (CIN) = $15J\;kg^{-1}$, Storm Relative Helicity (SRH) = $160m^2s^{-2}$, and 0~3 km bulk wind shear = $5s^{-1}$. About 34% of the cases were associated with a Changma front; this pattern is more significant than other synoptic pressure patterns such as troughs (22%), migratory cyclones (15%), edges of high-pressure (12%), typhoons (11%), and low-pressure originating from Changma fronts (6%). The spatial distribution of thermo-dynamic conditions (CAPE and SRH) is similar to the range of thunderstorms over the United States, but extreme conditions (supercell thunderstorms and tornadoes) did not appear in the Korean Peninsula. Synoptic conditions, vertical buoyancy (CAPE, CIN), and wind parameters (SRH, shear) are shown to discriminate among the environments of the three types. The first type occurred with high CAPE and low wind shear by the edge of the high pressure pattern, but Second type is related to Changma front and typhoon, exhibiting low CAPE and high wind shear. The last type exhibited characteristics intermediate between the first and second types, such as moderate CAPE and wind shear near the migratory cyclone and trough.

• 한국해양학회지
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• v.18 no.1
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• pp.64-72
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• 1983

A series of sheps-of-opportunity sea sryface temperature (SST) measurement beween Jeju and Wando during a period from December 1979 through June 1981 produced following results. 1. A sihnificantly warm water appeared south of Chuja Island and Cheongsan Island during Island. It is suggested that this water represents a current entering the Jeju Strait from the west. Direction of this currint in other seasons is not certain. 2. Coastal waters were found north of the Cheongsan Island and Bogil Islhnd throughout the measurement period. In February these waters sometimes reached as far as Chuja Island to south. 3. Frequently thermal fronts were observed near the Chuja Island and the Cheongsan Island. 4. In summer cold waters appeared north of the Chuja Island and Changsu Island. Intrusion of cold bottom water from offshore and its subsequent vertical mixing due to strong tidal current are probably reponsible for this appearance. 5. Cold waters also appeared locally around islands and in ghe Jeju Harbor in spring and summer. 6. North-south SST difference reached 8-9$^{\circ}C$ in winter which is the annual maximum. 7. Annual range of SST varies from 12-14$^{\circ}C$ in the central part of the Jeju Strait to 16-20$^{\circ}C$ in coastal waters to north. The highest SST appeared everywhere in September but the lowest one did not appesr in the same month of year.

• Journal of Fisheries and Marine Sciences Education
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• v.23 no.3
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• pp.425-432
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• 2011

In order to understand the characteristics of the distribution and the nutrients of the Yellow Sea Bottom Cold Water during summer to fall, temperature, salinity and nutrients have been investigated in the fifteen stations in the Yellow Sea. In september, the Changjiang diluted water with more than $20^{\circ}C$ distributed in the surface and the Yellow Sea Bottom Cold Water distributed in the layer below 30m depth with less than $10^{\circ}C$. Specially, water mass with less than $5^{\circ}C$ in the layer below 50m depth expanded southward down to the north latitude of $35^{\circ}$ with expanding more to the coasts of China than to the coasts of Korea. The salinity of the cold water mass with $8^{\circ}C$ in the deep layer of more than 50m depth was relatively high as 33.5 psu and expanded northward forming fronts of temperature and salinity. The concentration of total inorganic nitrogen was two times higher in the cold water mass than in the surface water, which means that resolution and consumption were low due to cold temperature in the bottom layer. In conclusion, the cold water expanded southward down to the north latitude of $35^{\circ}$ by September and had high concentration of nutrients.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.42.3-43
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• 2009

Triplets of identical cubesats will be built to carry out the following scientific objectives: i) multi-observations of ionospheric ENA (Energetic Neutral Atom) imaging, ii) ionospheric signature of suprathermal electrons and ions associated with auroral acceleration as well as electron microbursts, and iii) complementary measurements of magnetic fields for particle data. Each satellite, a cubesat for ion, neutral, electron, and magnetic fields (CINEMA), is equipped with a suprathermal electron, ion, neutral (STEIN) instrument and a 3-axis magnetometer of magnetoresistive sensors. TRIO is developed by three institutes: i) two CINEMA by Kyung Hee University (KHU) under the WCU program, ii) one CINEMA by UC Berkeley under the NSF support, and iii) three magnetometers by Imperial College, respectively. Multi-spacecraft observations in the STEIN instruments will provide i) stereo ENA imaging with a wide angle in local times, which are sensitive to the evolution of ring current phase space distributions, ii) suprathermal electron measurements with narrow spacings, which reveal the differential signature of accelerated electrons driven by Alfven waves and/or double layer formation in the ionosphere between the acceleration region and the aurora, and iii) suprathermal ion precipitation when the storm-time ring current appears. In addition, multi-spacecraft magnetic field measurements in low earth orbits will allow the tracking of the phase fronts of ULF waves, FTEs, and quasi-periodic reconnection events between ground-based magnetometer data and upstream satellite data.

• Korean Journal of Plant Taxonomy
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• v.33 no.4
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• pp.455-472
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• 2003

The period from 1946 until his retirement from Department of Forest Resources, Seoul National University was a time of research and professional activity on many fronts for Korean Plant Taxonomy. From 1952 to 1984, he travelled south Korea and collected more than 70,000 specimens. Working out of this project, Dr. Lee developed the SNUA herbarium (Herbarium of The Arboretum of Seoul National University) as the best University herbarium in Korea for the modem floristic work. Dr. Lee's first interest rests on his contributions to our understanding of the twig identification in early 1950. Asian deciduous oak taxa have attracted particular focus to him late 1950 and early 1960. Accordingly Dr. Lee has been one of the specialists on systematic study of Asian oak which is a basis of identification in eastern Asia now. Dr. Lee's contributions concerning rare and endangered plants in Korea provide a tremendous information after a Japanese taxonomist, T. Nakai did in early 1920 to late 1930 in Korea. During his fourteen year career from 1970 to 1984, Dr. Lee spent time to investigate flora of many local and National Park sites. Much of his effort was directed to the voucher specimens for which he worked for the Illustrated Flora of Korea and also served as a field collector. These collections at SNUA enabled us to extend our educational outreach from the local to the national flora research. Although Dr. Lee has been and continues to be the soul of SNUA, collection records about his purpose and aim for each trip are not well documented except date and field studied sites. This lesson enables us to tackle the same issue of balancing quantity and quality with well documented specimens now.

• International Commerce and Information Review
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• v.13 no.4
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• pp.463-484
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• 2011

The survey was conducted by Chinese students who currently attend universities for the purpose of evaluating factors that determine the quality of educational services of universities in Korea. Three public universities and five private universities in Kyungsang province were surveyed for the purpose of this study with standardized questionnaires. The study raised questions on four different fronts: 1) Is there a difference in the importance of evaluation factors by Chinese student's on the quality of educational services between public universities and private ones? 2) Is there a difference in the degree of satisfaction felt by Chinese students who attend public universities or private ones? 3) Are there any significant differences in the importance of evaluation factors and satisfaction with the quality of educational services? 4) How different the relative influence of evaluation factors has on satisfaction with the quality of educational services for overall Korean university system? The results of this study showed that there was no statistical difference in signification in the importance of evaluation factors on the quality of educational services between public universities and private universities. Only the relationship factor in criteria four had an effect on satisfaction with quality of educational services between public and private universities. There were significant differences in the importance of evaluation factors and satisfaction with the quality of educational services. Chinese students determined that professor's lectureship as the most important factor, and is the ultimate deciding factor whether they attend a public or private university. It should be noted that studying and knowledge are primary concerns to them. Improvements in the quality of educational services in area of lectureship, physical education facilities, relationship, and administrative services are essential and crucially important for Korean universities in order to attract foreign students and to enhance their competitiveness in the global setting.

• Journal of the Korean earth science society
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• v.30 no.2
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• pp.223-233
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• 2009

Three-dimensional (3-D) optimally-interpolated sea surface temperature (SST) field was produced by using AQUA/AMSR-E satellite data, and its limitations were described by comparing the temporal average of sea surface temperatures. The 3-D OI (Optimum Interpolation) SST showed a small error of less than $0.05^{\circ}C$ in the central North Pacific, but yielded large errors of greater than $0.4^{\circ}C$ at the coastal area where the satellite microwave data were not available. OI SST composite around pixels with no observation due to heavy rainfall or cloudy pixels had estimation errors of $0.1-0.15^{\circ}C$. Comparison with temporal means showed a tendency that overall OI SSTs were underestimated around heavy cloudy pixels and smoothed out by reducing the magnitude of SST fronts. In the low-latitude areas near the equator, OI SST field produced discontinuity, originated from the window size for the OI procedure. This was mainly caused by differences in the spatial scale of oceanic features. Infernal Rossby deformation radius, as a measure of spatial stale, showed dominant latitudinal variations with O(1) difference in the North Pacific. This study suggests that OI SST methodology should consider latitudinally-varying size of window and the characteristics of spatial scales of oceanic phenomena with substantial dependency on latitude and vertical structure of density.

• Journal of the Korean earth science society
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• v.29 no.3
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• pp.280-289
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• 2008

An extensive set of both in-situ and satellite data regarding oceanic sea surface temperatures in Northeast Asian seas, collected over a 10-year period, was collocated and surveyed to assess the accuracy of satellite-observed sea surface temperatures (SST) and investigate the characteristics of satellite measured SST errors. This was done by subtracting insitu SST measurements from multi-channel SST (MCSST) measurements. 845 pieces of collocated data revealed that MCSST measurements had a root-mean-square error of about 0.89$^{\circ}C$ and a bias error of about 0.18$^{\circ}C$. The SST errors revealed a large latitudinal dependency with a range of $\pm3^{\circ}C$ around 40$^{\circ}N$, which was related to high spatial and temporal variability from smaller eddies, oceanic currents, and thermal fronts at higher latitudes. The MCSST measurements tended to be underestimated in winter and overestimated in summer when compared to in-situ measurements. This seasonal dependency was discovered from shipboard and moored buoy measurements, not satellite-tracked surface drifters, and revealed the existence of a strong vertical temperature gradient within a few meters of the upper ocean. This study emphasizes the need for an effort to consider and correct the significant skin-bulk SST difference which arises when calculating SST from satellite data.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.2
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• pp.64-69
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• 2004

The results of analyzing the hydrographic observations in the southwestern sea of Jeju Island in the last 10 days of August 1999 to investigate the characteristics of oceanic front area appeared in the East China Sea in August from is summarized as follows: In Line A, a front appears at Station A5 of 124°E and 31°30'N, showing relatively uniform density of 21.4 to 22.1 in the surface layer of 50m depth, which is distinguished from 22.0 shown in the sides of China and open ocean. In Line B, a front also appears at Station B6 of 124°E and 33°N, of which density is distinguished from 20.0 shown in the sides of China and open ocean as In Line A. As a result, the front area caused by fresh water runoffs from the Yangtze River in the East China Sea is formed at 124°E and 124°30'in the direction of east and northeast from Yangtze River, respectively. Nutrient concentrations in the study area are characterized by higher density in the side of China and by clear density difference between the upper and the lower layers in the side of open ocean, while by uniformly lower density concentration between the upper and the lower layers in the front area. Chlorophyll-α concentrations is high in the sides of China and open ocean, while low in the front area. Judging from the above results, the productivity in the front area is lower according to the inactivity of phytoplankton due to increased flow from vertical mixing between the upper layer and the lower layer. Also, the front area in the East China Sea in summer may be moved towards the adjacent sea of Jeju Island by increasing fresh water runoffs from the Yangtze River in summer.

• Ocean and Polar Research
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• v.43 no.4
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• pp.279-293
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• 2021

To investigate the effect of seasonal marine environment conditions on the cyanobacteria abundance and diversity in the South Sea, four-seasonal surveys were conducted along the 127.5°E survey transect line in the central South Sea using flow cytometry and 16S-23S ITS on the Miseq platform from August 2016 to May 2017. The average abundance of Synechococcus varied from 3.3 × 10³ to 7.4 × 10⁴ cells ml^-1. The abundance was the highest in the summer and the lowest in the winter, and the abundance fluctuated according to water temperature. The abundance was high in the outer sea affected by TWC. However, in summer, the Coastal areas affected by the Yangtze River were more populated than the outer sea. Prochlorococcus was rare and could not penetrate into coastal areas due to the fronts, but showed its dominance in the waters influenced by the TWC. Synechococcus clades II, VII, IX, CRD1, and CRD2 were predominant in the outer sea area affected by the TWC. In the coastal area, clades I and IV showed higher dominance whereas clades V, VI, WPC1, and 5.3-MS3 with euryhaline characteristics, showed a high dominance rate in the water masses affected by the low-salinity water of the Yangtze River in the summer. Clade XVI, XVII, CB1, CB5, and 5.3-I/II showed high dominance in nutrient-rich waters in the summer with increased water temperature. The abundance and community composition of cyanobacteria changed in the South Sea due to the influence of the TWC and stratification. In the summer, the abundance and the community composition differed, and were mainly affected by the general influence of the TWC in addition to the influence of the Yangtze River low-salinity water.