• Fire Science and Engineering
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• v.19 no.4 s.60
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• pp.1-6
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• 2005

To control forest fire effectively, it is necessary to understand forest fire behavior and relevance to forest fire environmental factors. In this paper, the behavior characteristics of the 2005 Yangyang forest fire were analyzed into the spread patterns and severity grades. The spread processes of the forest fire could be divided into two steps. At the first step, the fire ran fast to the east due to the strong west wind and then spreaded out in irregular direction. The maximum spread rate of the fire was 1.21km/hr and the mean was 0.65 km/hr. The result of the fire severity classification indicated that about $80\%$(1,110ha) of the whole study site was extremely burned and the remaining $15\%(211 ha)\;and\;5\%(61 ha)$ were damaged slightly and moderately respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.551-551
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• 2017

우리나라와 동아시아는 경제 성장에 따른 전력수요가 크게 증가하였으며, 증가하는 대부분의 전력수요를 원자력으로 대체하고자 원전을 통한 전력생산 비중을 증가시키고 있다. 현재 중국은 13기의 원전을 가동 중이며, 동남 해안지대에 집중되어 있다. 또한, 건설 중인 원전은 27기로 전세계에서 건설 중인 원전의 41%를 차지한다. 원전의 증가에 따른 방사능 누출에 대한 위험성 역시 증가되고 있는 실정이다. 한국원자력안전기술원에서 중국 중서부지역에서 방사능이 누출될 경우 방사성 물질이 한반도로 이동하는 모의 상황에 대한 시뮬레이션을 통해, 원전 사고 발생 시 사흘 만에 제주도를 포함한 대한민국 전역이 방사성 물질로 뒤덮이는 것으로 분석하였다. 중국에서 누출된 방사성물질은 편서풍을 타고 한반도로 이동하게 되며, 일부는 낙진으로 유역 또는 하천에 유입되고 일부는 동해를 지나 일본으로 이동 할 것이다. 그동안 중국에서의 방사능 누출사고를 통한 방사성물질의 국내유입에 의한 영향에 대한 연구가 부족한 것이 현실이다. 이에 본 연구에서는 중국 텐완에서 원전사고 발생시 국내 하천에 어떠한 영향을 미치는지 분석하고자 환경다매체 모형을 이용하여 방사성물질(세슘, Cs-137)의 영향에 대한 모의를 진행하였다. 중국 텐완원전에서 방사성 Cs-137이 누출되어 춘천지역에 도달하였을 때의 대기중 농도 $5,650Bq/m^3$로 가정하여 모의 시나리오를 구성하였다. 모의 지역은 북한강 수계를 대상으로 하였으며, 7개의 중권역과 549.3 km의 하천이 포함되었다. 다매체 모형 모의를 통해 방사성물질 낙진으로 인한 Cs-137이 북한강 수계에 어떠한 영향을 미치는지 알아보고자 북한강수계의 팔당댐 부근의 오염농도를 모의하였다. 우리나라의 원자력시설 방호 방재법에 따른 상수원 취수기준(먹는물)은 100 Bq/L로 되어있다. 본 연구의 시나리오 모의결과, 모의 1일차에서 45 Bq/L, 모의 8일차에는 먹는물 기준 100 Bq/L를 초과하여 최대 119.56 Bq/L로 오염되는 것으로 모의되었다. 따라서, 반감기가 큰 방사성물질을 유입으로 오염된 하천은 개선하기 위해서는 오랜 시간과 높은 처리비용이 발생되기 때문에 인접국 또는 국내의 방사능 누출로 인한 상수원 오염 발생에 대비한 초기/중 장기적인 대응책 마련이 필요한 시점이다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.4
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• pp.139-149
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• 2019

As of 2018, a large amount of Chinese fine dust is flowing into Korea in westerlies. However, the amount of fine dust generated in Korea can not be ignored. Even 52% of the causes of fine dust are domestic factors. Especially in Seoul, where the population is densely populated, the dust levels are high enough to be comparable to other regions. In Seoul, the dust levels are different from each other district. In order to understand the difference of fine dust generation by distinction, it is judged based on the highest traffic volume among the causes of fine dust generation in Seoul. Comparing the traffic volume and the fine dust concentration in 2017, it is possible to know the effect of traffic volume actually, how much it affects.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.83-93
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• 2006

The Kita-Yamato Trough is characterized by a SW-NE trending narrow graben between the Yamato Bank and the Kita-Yamato Bank in the central East Sea/Japan Sea (ES/JS). Core 20EEZ-1 was obtained in the flat summit of a small ridge from the southwest Kita-Yamato Trough. The sedimentation was mainly controlled by the supply of hemipelgic sediments and substantial tephras from explosive volcanic eruptions of the Quaternary volcanoes. The aim of this study is to reconstruct the tephrostratigraphy from the marine sediments collected from the Kita-Yamato Trough and to provide the atmosphere and ocean conditions during the explosive volcanic eruptions. According to the detailed tephrostratigraphy and lithofacies records, the core sediments were deposited during the last marine isotope stage (MIS) 7. The core consists of four lithofacies, idetified as, oxidized mud (OM), crudely laminated mud (CLM) and bioturbated mud (BM), interbedded with coarse-grained tephra (TP). The major element geochemistry and stratigraphic positions of seven tephra layers suggest that they originated from the Aira caldera in Kyushu area among the Japanese islands (AT tephra; 29.24 ka), unknown submarine volcano in the south Korea Plateau (SKP-I; MIS 3, SKP-II; MIS 4, SKP-IV; boundary between MIS 6 and MIS 5e, SKP-V; MIS 6, respectively), and the Baegdusan volcano in the Korean Peninsula (B-KY1; ca. 130 ka, B-KY2; ca. 196 ka). The absence of tephras originated trom Ulleung Island in core 20EEZ-l suggest that the tephras had not been transported into the Kita-Yamato Trough by atmosphere conditions during the eruptions. On the other hand, the B-KYI and the B-KY2 tephras derived from the Baegdusan volcano were founded in the Kita-Yamato Trough by a presence of prevailing westerly winds during the eruptions. Furthermore, the SKP tephras were characterized by the transport across the air-water interface, causing quickly thrust of raising eruption plumes from subaqueous explosive eruptions. Surface currents may play an important role in controlling the distribution patterns of the SKP tephras to distal areas. The tephrostratigraphic study in the Kita-Yamato Trough provides the important chronostratigraphic marker horizons and the detailed atmosphere and ocean conditions during the explosive eruptions.

• Journal of the Korean earth science society
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• v.25 no.6
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• pp.474-483
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• 2004

This paper analyzed the characteristics of daily ozone variations over Kangreung and Wonju. It was found that the diurnal cycle of ozone over Wonju has a primary ozone peak in the afternoon and a minimum around sunrise, which is a typical diurnal ozone cycle observable in the urban area. However, the cycle over Kangreung shows a primary peak in the afternoon and secondary peak around 3 a.m. The amounts of ozone in the secondary peak is occasionally higher than that in the primary peak. This nocturnal ozone peak is frequently observed year-round, and the highest frequency and extent are observed in spring. The possible cause of this nocturnal ozone increase was investigated using meteorological parameters and the HYSPLIT trajectory model. It was found that the nocturnal ozone peak is highly correlated with strong wind speed, which has led to positive temperature anomaly. The trajectory model revealed that when the secondary peak occurred, the air was originated from the west and a sinking motion subsequently followed. These findings suggested that when the westerly wind is strongest in spring, the polluted airs from urban areas are transported to the upper boundary layer over Kangreung area. In the case of strong wind during the night, nocturnal ozone peaks were produced by active vertical mixing between lower boundary and upper boundary layers.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.284-288
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• 2001

This study was carried out to investigate the chemical properties of rainwater in Taean area. Rainwater was collected during seven months from April to October in 2000, and analyzed for its chemical composition. The pH of rainwater at April and May were higher than those from June to September. Occurrence rate of rain above pH 5.6 was 42.1%, which showed the highest ratio from rainwater samples during investigation periods. Those of pH $5.0{\sim}5.6$ and $4.5{\sim}5.0$ range were 21.1 and 31.6%, respectively. The major cation in rainwater were $Ca^{2+}$ and $NH_4\;^+$, and $SO_4\;^{2-}$ was more than 50% of total anion composition. Monthly variation of acidity neutralization capacity by $Ca^{2+}$ and $NH_4\;^+$ was decreased during rainy season. The $nss-SO_4\;^{2-}/NO_3\;^-$, ratio was 2.0 which means $SO_4\;^{2-}$ contributed to acidity of rainwater two times more than $NO_3\;^-$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.5 no.1
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• pp.1-5
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• 2003

This study was carried out to investigate the chemical properties of rainwater in the Suwon area. Rainwater was collected from April to October in 1999 and 2000, and its chemical composition was analyzed. The pH of rainwater in April was higher than that of the months after June. Occurrence frequency of rain above pH 5.6 was 45.1%, which showed the highest ratio from rainwater samples during the investigation periods. Those of pH 5.0∼5.6 and 4.5∼4.9 range were 31.4 and 19.6%, respectively. The major cations in rainwater were $Ca^{2+}$ and N $H_{4}$$^{+}$, and S $O_{4}$$^{2-}$ made up more than 50% of total anion composition. Monthly variation of neutralization capacity of rainwater acidity by $Ca^{2+}$ and N $H_{4}$$^{+}$ decreased during the rainy season. The ratio of non-sea salt sulfate to nitrate (nss-S $O_{4}$$^{2-}$/N $O_{3}$$^{[-10]}$ ) was 2.1, which means anthropogenic S $O_{4}$$^{2-}$ contributed to acidity of rainwater two times more than N $O_{3}$$^{[-10]}$ . .

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.1
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• pp.16-24
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• 1998

In this study, Ocean General Circulation Model (OGCM) has been developed as a counterpart of Atmospheric General Circulation (AGCM) for the study of coupled ocean-atmosphere climate system. The oceanic responses to given atmospheric boundary conditions have been investigated using the OGCM. In an integration carried out over 100 simulated years with climatological monthly mean data (EXP 1), most parts of the model reached a quasi-equilibrium climate reproducing many of the observed large-scale oceanic features remarkably well. Some observed narrow currents, however, such as North Equatorial Counter Current, were inevitably distorted due to the model's relatively coarse resolution. The seasonal changes in sea ice cover over the southern oceans around Antarctica were also simulated. In an experiment (EXP 2) under boundary condition of 10-year monthly data (1982-1991) from NCEP/NCAR Reanalysis Project model properly reproduced major oceanic changes during the period, including El Ni$\tilde{n}$os of 1982-1983 and 1986-87. During the ENSO periods, the experiment showed eastward expansion of warm surface waters and a negative vertical velocity anomalies along' the equator in response to expansion of westerly current velocity anomalies as westerly wind anomalies propagated eastward. Simulated anomalous distribution and the time behavior in response to El Ni$\tilde{n}$o events is consistent with that of the observations. These experiments showed that the model has an ability to reproduce major mean and anomalous oceanic features and can be effectively used for the study of ocean-atmosphere coupling system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.474-482
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• 2021

An average of two to three typhoons that occur in the Philippines or Taiwan pass through Korea each year owing to the influence of the geographical location and western winds. Because Jinhae Bay is known as Korea's representative typhoon refuge, it is filled with ships during typhoons and later becomes saturated with ships anchored to the surrounding routes. If a strong wind drags an anchored ship, a collision accident may occur because of the short distance between the ships. Therefore, a systematic anchoring safety management of Jinhae Bay is required. In this study, the minimum wind speeds of a dragging anchor based on the water depths of Jinhae Bay anchorages were investigated. When 7-9 shackles were given, the minimum wind speeds were 48-63, 46-61, and 39-54 knots at depths of 20, 35, and 50 m, respectively. As the water depth increased, the length of the cable laid on the sea bed became shorter than 5 m owing to the external force, and the minimum wind speed showed a significant difference of 4-8 knots. In addition, ships with high holding power anchors (AC-14 type) had higher minimum wind speeds than ships with conventional anchors (ASS type). Finally, it was confirmed that at a depth of 50 m, dragging easily occurred even when a high holding power anchor was applied.

• Korean Journal of Environmental Biology
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• v.40 no.2
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• pp.214-223
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• 2022

Among migratory insect pests, Mythimna seperata and Cnaphalocrocis medinalis are invasive pests introduced into South Korea through westerlies from southern China. M. seperata and C. medinalis are insect pests that use rice as a host. They injure rice leaves and inhibit rice growth. To understand the distribution of M. seperata and C. medinalis, it is important to understand environmental factors such as temperature and humidity of their habitat. This study predicted current and future habitat suitability models for understanding the distribution of M. seperata and C. medinalis. Occurrence data, SSPs (Shared Socio-economic Pathways) scenario, and RCP (Representative Concentration Pathway) were applied to MaxEnt (Maximum Entropy), a machine learning model among SDM (Species Distribution Model). As a result, M. seperata and C. medinalis are aggregated on the west and south coasts where they have a host after migration from China. As a result of MaxEnt analysis, the contribution was high in the order of Land-cover data and DEM (Digital Elevation Model). In bioclimatic variables, BIO_4 (Temperature seasonality) was high in M. seperata and BIO_2 (Mean Diurnal Range) was found in C. medinalis. The habitat suitability model predicted that M. seperata and C. medinalis could inhabit most rice paddies.