• 한국지구과학회지
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• 제27권6호
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• pp.653-658
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• 2006

대기 대순환 모형인 GCPS를 이용하여 북서태평양에서의 태풍 활동의 계절 예측 가능성을 조사하였다. 1979년부터 2003년까지 각 해에 대해 해수면 온도 관측 자료를 사용하여 5개월간 초기 조건을 달리한 10개의 앙상블 멤버를 적분하였다. 모형은 발생 빈도의 평균적인 월변화 경향과 발생 분포를 관측과 유사하게 모의하였으나, 발생 빈도의 경년 변화는 신빙성 있게 예측하지 못하였다. 이는 관측과 모형간 태풍 발생 빈도와 ENSO의 상관성 차이에 인한 것으로 실제 태풍 발생 빈도와 ENSO가 뚜렷한 상관 관계를 갖지 않는 것과 달리, 모형에서는 엘니뇨 시기에 평년에 비해 많은 태풍이 발생하고 라니냐 시기에 평년에 비해 적은 태풍이 발생하는 경향을 보였기 때문이다. 반면에, 관측과 모형 모두 ENSO와의 상관 관계가 높게 나타난 태풍 발생 경도의 경우에는 모형이 발생 경도의 경년 변화를 관측과 유사하게 모의하였다.

• 한국지구과학회지
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• 제25권4호
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• pp.277-288
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• 2004

서해 상에서 저기압과 태풍 통과 시 해상상태를 비교 분석을 하였다. 1999년 4월 9일${\sim}$12일에 강한 저기압이 화중지방에서 발생하여 서해를 지나 한반도에 영향을 미친 경우의 9905호 태풍 NEIL과 9907호 태풍 OLGA가 서해를 통과하면서 서해 연안에 영향을 미친 사례이다. 봄철 이동성 저기압 발생 시 에는 저기압 중심부의 풍속이 주변 지역에 비해 위상이 빠르고 강하게 나타나며, 이에 수반되어 발생하는 파고는 주변의 지형적 영향으로 다르게 나타날 수 있다. 이에 비해 두 태풍에 의해 발생한 파고는 태풍 Olga가 서해 남부해역에서 북상할 시기에 칠발도 근해상에서 5m이상의 높은 유의파고를 발생한 것 이외에는 저기압 통과 시보다 파고가 낮다. 해일도 태풍보다 저기압 통과 시에 더 크게 나타나는데, 이러한 결과는 강하지만 국지적이고 빠르게 이동하는 태풍보다 종관적이고 느리게 이동하는 기압장에 의해 발생한 파도와 해일이 더 클 수 있음을 보여준다.

• 한국지형학회지
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• 제24권3호
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• pp.83-103
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• 2017

Sand deposit with shell units is exposed in Hasa-ri, Yeonggwang-gun, Jeonnam province. We investigated the characteristics of sand sediment topography in the Yeonggwang coastal area to collect evidence of the paleo-environmental change. We performed analysis on particle characteristics, chemical composition, and the age of deposition of sediments. The deposit comprise moderately well sorted medium and fine sand ($1.00{\sim}2.19{\varphi}$). Various sedimentary structures can be observed. Geochemical characteristics change by depth and the degree of variation with depth is small. The results obtained from OSL dating show that sand layers below shell units are deposited 0.32-0.43 ka. As the elevation of the shell unit far mean high water levels or highest high water level, the extensive shell layers could only have been deposited during storm surge conditions. Aeolian processes are discounted due to the size of clasts and the location at which they occur. Results of age dating of the surrounding deposits indicate shell deposits formed after around 300 years age. There is a distinct difference between sedimentary layers including dark brown-black layer. The sedimentary characters such as particle size and geochemistry show difference with depth. It is presumed that depositional environmental in Hasa-ri has changed several times before. This study is expected to contribute to finding an evidence about occurrence of storm surges.

• Coupled systems mechanics
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• 제2권1호
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• pp.111-126
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• 2013

The structural design requirements of an offshore platform subjected to wave induced forces and moments in the jacket can play a major role in the design of the offshore structures. For an economic and reliable design; good estimation of wave loadings are essential. A nonlinear response analysis of a fixed offshore platform under structural and wave loading is presented, the structure is discretized using the finite element method, wave plus current kinematics (velocity and acceleration fields) are generated using 5th order Stokes wave theory, the wave force acting on the member is calculated using Morison's equation. Hydrodynamic loading on horizontal and vertical tubular members and the dynamic response of fixed offshore structure together with the distribution of displacement, axial force and bending moment along the leg are investigated for regular and extreme conditions, where the structure should keep production capability in conditions of the 1-yr return period wave and must be able to survive the 100-yr return period storm conditions. The result of the study shows that the nonlinear response investigation is quite crucial for safe design and operation of offshore platform.

• Ocean and Polar Research
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• 제25권3호
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• pp.303-314
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• 2003

The initiation of Cochlodinium polykrikoides blooming in the South Sea of Korea occurs in the sea near Naro-Do in late August. In this paper, the relationships of this annual occurrence with the environmental conditions are presented. In early summer, the winds in the sea near Naro-Do are southwesterly and the upwelling occurs in the near-shore area. The favorable winds to the upwelling are relaxed in August and the downwelling favorable northeasterly winds set in around late August. The change of wind direction causes the onshore transport of warm-and-fresh off-shore water into the sea near Naro-Do and a front between near-shore water and off·shore water is formed. Along the front, downwelling occurs and the environmental conditions for the diatom become unfavorable. When the typhoon and storm bring well-mixed East China Sea water into the sea near Naro-Do in September, the conditions for the dinoflagellates become unfavorable and blooming of C. polykrikoides disappears.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.543-549
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• 2000

Water quality was monitored from a watershed with small-scale livestock production farms. To evaluate pollution potential, land use, population, the size of livestock production of each farm, and livestock management were surveyed. Climate and stream flow data were gathered. Water samples were taken periodically for base conditions and some storm events. Pollutant loading was estimated by flow volume and concentrations of constituents.

• 한국측량학회지
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• 제28권6호
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• pp.655-662
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• 2010

최근 지구 온난화와 이상기후로 인하여 자연재해로 인한 피해가 지속적으로 발생하고 있으며, 이로 인한 피해가 점차 대형화되고 있다. 본 연구는 기존 기술에 비해 신속하고 경제적이면서, 다양한 재난 재해에 활용이 가능한 UAV(Unmanned Aircraft Vehicle)를 통해 자연재해에 의한 피해를 효과적으로 대비, 대응 및 복구할 수 있는 활용모델을 제시하기 위한 선행연구로 기존 재해관련 연구사례와 국내 재해관련 규정 분석을 바탕으로 재해모니터링을 위한 UAV의 적용성을 분석하였다. 향후, 자연재해 모니터링을 위한 UAV의 활용은 재난 재해 대응관리 및 피해조사를위한실시간공중모니터링을가능하게 함으로써 재난 재해 대응 및 관리의 효율성을 향상시킬 것이다.

• 한국물환경학회지
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• 제24권3호
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• pp.345-353
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• 2008

In order to design storage-based non-point source management facilities, the aspect of statistical features of the entire precipitation time series should be considered since non-point source pollutions are delivered by continuous rainfall runoffs. The 3-parameter mixed exponential probability density function instead of traditional single-parameter exponential probability density function is applied to represent the probabilistic features of long-term precipitation time series and model urban stormwater runoff. Finally, probability density functions of water quality control basin overflow are derived under two extreme intial conditions. The 31-year continuous precipitation time series recorded in Busan are analyzed to show that the 3-parameter mixed exponential probability density function gives better resolution.

• 한국물환경학회지
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• 제25권1호
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• pp.26-36
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• 2009

Combined sewer system (CSS) has been built in the most urban areas across the nation. During dry weather conditions, CSS works fine. But during heavy rain storms, combined sewage frequently overflows into the stream. This study simulated the hydrologic cycle and pollutant loads (BOD, SS, TN and TP) in the Mokgamcheon watershed considering combined sewer overflows (CSOs). PC storm water management model (PCSWMM) was used for continuous simulation and CSOs are considered using the flow divider. Sensitivity analysis, calibration and verification for water quantity and quality are carried out. To verify CSOs, field measurements of CSOs are compared with simulated results. As a result, 41.3% of precipitation flows into the stream directly and 1.1% of water supply flows into stream as CSOs. 6.5% of BOD total loads, 12.0% of SS, 13.6% of TP, and 29.2% of TN are from CSOs. This result will be effective to the integrated watershed management for sustainability.

• 농촌계획
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• 제6권2호
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• pp.43-49
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• 2000

Buffer zone selection technique for natural purification of livestock wastewater within a small agricultural watershed was developed using Geographic Information Systems. The technique was applied to $4.12\;km^2$ watershed located in Gosan-myun, Ansung-gun which have 20 livestock farmhouses. As a necessary data for selecting process, feedlot site map, digital Elevation Model (DEM), stream network, soil and land use map were prepared. By using these data, wastewater moving-path tracing program from each feedlot to the stream was developed to get the basic topographic factors; average slope through the paths, distance to the nearest stream and watershed outlet. To identify the vulnerable feedlots for storm event, the grid-based storm runoff model (Kim, 1998; Kim et al., 1998) was adopted. The result helps to narrow down the suitable area of buffer zone, and finally by using subjective but persuasive conditions related to elevation, slope and land use, the suitable buffer zones were selected.