• Wind and Structures
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• 제30권6호
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• pp.547-558
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• 2020

With the development of economy and construction technology, more and more bridges are built in complex mountainous areas. Accurate assessment of wind parameters is important in bridge construction at complex terrain. In order to investigate the wind characteristics in the high-altitude difference area, a complex mountain terrain model with the scale of 1:2000 was built. By using the method of wind tunnel tests, the study of wind characteristics including mean wind characteristics and turbulence characteristics was carried out. The results show: The wind direction is affected significant by the topography, the dominant wind direction is usually parallel to the river. Due to the sheltering effect of the mountain near the bridge, the wind speed and wind attack angle along the bridge are both uneven which is different from that at flat terrain. In addition, different from flat terrain, the wind attack angle is mostly negative. The wind profiles obey exponential law and logarithmic law. And the fitting coefficient is consistent with the code which means that it is feasible to use the method of wind tunnel test to simulate complex terrain. As for turbulence characteristics, the turbulence intensity is also related to the topography. Increases sheltering effect of mountain increases the degree of breaking up the large-scale vortices, thereby increasing the turbulence intensity. Also, the value of turbulence intensity ratio is different from the recommended values in the code. The conclusions of this study can provide basis for further wind resistance design of the bridge.

• 한국대기환경학회지
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• 제16권2호
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• pp.151-158
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• 2000

Since Pusan metropolitanarea where is composed complex terrain is connected to sea the sea-land breeze circulation and the mountain-valley circulation are apt to form A regional scale circulation system is formed at a region which has complex terrain because of curves of its and affect to the dispersion and advection of air pollutants. LCM Local Circulation Model which a propriety was verified described that sea breeze and valley wind at the daytime and land breeze and mountain wind at the nighttime were well devellped over the Pusan metropolital area. Next for the investigation of accuracy of simulated results an observed value at Kae-Kum and Su-Young on the pusan metropolitan area were compared with it at those points. From the comparison of the temperature and horizontal velocity between the results of LCM and an observed values they have a similar trend of a diurnal variation. For the prediction of dispersion and transportation of air pollutants the wind field should be calculated with high accuracy. A numerical simulation using LCM can provide more accuracy results around Pusan metropolitan area.

• 한국환경복원기술학회지
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• 제19권6호
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• pp.101-110
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• 2016

Development activities in forest areas are analysed based on degree of slope, altitude, land cover, and prefectures in order to improve the capacity of existing regulations of 'feasibility of forest land conversion' and 'assessment of forest land characteristics' in this research. 959 land based developments between year 2007 and 2013 have been analysed. A development site includes over 50% of forest is categorized as a forest type, degree of slope is steeper than $8.5^{\circ}$ as mountain type, and a development included in the both categories as combined type. Distribution characteristics of the above three types are analysed by development categories and regions adopting Relative Mountain Development Index(RMDI). In results, 44.94% of total development activities have been carried out in Gyeongsang Do in order of urban development, industrial complex, sports facilities, and soil and stone collection quarrying. Developments less than $0.3km^2$ which are exempt from the feasibility of forest land conversion regulation consist 86 cases of forest type, 78 cases in mountain type, and 78 cases in combined type. SAI by slope range showed the highest value of 1.55 in less than $5^{\circ}$ and the lowest value of 0.69 between $20^{\circ}-25^{\circ}$. RMDI value in Gyeongsang Do where mountain ratio is 67.05% appeared 1.17, which is 5 times more than Gangwon Do where mountain area ratio is 81.30%, and 2 times more than Chungchung Do where mountain area ratio is 51.24%. Development activities in forestland in Korea showed unequal distributions and 26% of those developments were not subjected to the feasibility of forest land conversion regulation.

• 대기
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• 제25권1호
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• pp.51-66
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• 2015

This study was conducted to perform various sensitivity experiments using WRF (Weather Research and Forecasting) model in order to determine the effects of terrains of the Korean Peninsula and the land-sea thermal contrast on the formation and development of the convergent cloud band for the cases of 1 February 2012. The sensitivity experiments consist of the following five ones: CNTL experiment (control experiment), and TMBT experiment, BDMT experiment and ALL experiment that set the terrain altitude of Taeback Mountains and Northern mountain complex as zero, respectively, and the altitude of the above-mentioned two mountains as zero, and LANDSEA experiment that set to change the Korean Peninsula into sea in order to find out the land-sea thermal contrast effect. These experiment results showed that a cold air current stemming from the Siberian high pressure met the group of northern mountains with high topography altitude and was separated into two air currents. These two separated air currents met each other again on the Middle and Northern East Sea, downstream of the group of northern mountains and converged finally, creating the convergent cloud band. And these experiments suggested that the convergent cloud band located on the Middle and Northern East Sea, and the cloud band lying on the southern East sea to the coastal waters of the Japanese Island facing the East Sea, were generated and developed by different dynamical mechanisms. Also it was found that the topography of Taeback Mountains created a warm air advection region due to temperature rise by adiabatic compression near the coastal waters of Yeongdong Region, downstream of the mountains. In conclusion, these experiment results clearly showed that the most essential factor having an effect on the generation and development of the convergent cloud band was the topography effect of the northern mountain complex, and that the land-sea thermal contrast effect was insignificant.

• 한국산림과학회지
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• 제94권4호통권161호
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• pp.214-225
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• 2005

한국의 산촌개발사업은 의제21(Agenda 21) 13장의 지속가능한 산지개발(SMD, Sustainable Mountain Development)과 국토 균형발전을 도모하기 위하여 전국토의 45.9%를 점유하고 있는 산촌마을을 대상으로 1995년부터 시범적으로 시작되었다. 이후 도별 확대사업과 함께 관련 법률 및 제도 정비를 통하여 산촌주민의 삶의 질 향상과 행복 제고를 목적으로 현재 진행 중이다. 본 연구는 2003년 현재 사업 완료된 59개 산촌개발마을과 조성중인 15개 산촌개발사업마을의 사업내용에 대하여 산촌개발의 핵심 이해관계자인 산촌주민과 지방자치단체 공무원의 의견을 비교분석하여 사업만족도를 분석하고 향후 지역사회 개발사업으로서 산촌개발 사업의 추진방향을 제시하고자 수행되었다. 산촌개발사업은 지역사회 개발사업이 일반적으로 추구하는 주민의 자발적 참여와 민주시민으로의 자립정신확립, 소득증진 기반조성, 쾌적한 생활환경의 창조, 타 지역과의 균형발전 등 여러 측면에서 긍정적인 성과가 나타났다. 특히 마을주민과 지방자치단체의 기대가 큰 소득증대 기반조성과 해적한 마을환경 기반구축을 통한 정주기능 증진효과에 대하여는 이해관계자 모두가 만족하는 성과가 도출되었다. 그러나 산촌개발사업을 통한 산촌마을의 지역사회유지 및 전통적인 가치체계 강화는 만족한 수준에 달하지 못하고 있다. 또한 지속적인 소득증진효과를 도모하기 위한 지역 특성에 알맞은 소득 작목 개발과 기술 보급, 지역특산물 개발 유통개선도 필요한 실정인데, 지방 자치단체의 적극적이며 다각적인 활동이 요구된다. 또한 산촌개발계획 초기부터 지방자치단체와 산촌주민이 공동 참여하는 산촌개발사업방식의 도입과 관련 지방행정조직과 1차 산업 단체의 혁신은 산촌개발사업의 지속성 유지를 위하여 바람직하다. 또한 산촌개발이 장기적으로 타 지역개발과의 균형 유지를 위한 종합개발 계획 수립, 산촌마을 네트워크 구성과 정보교환, 산촌개발사업 사후 시설관리, 산촌마을개발협의회 구성 등 산촌개발사업의 핵심요소인 지도인력의 양성과 교육은 중앙정부의 주도적인 지원을 요구한다. 향후 산촌관련 이해관계자를 고려한 발전 방안 수립은 지역사회개발계획의 일환으로 산촌개발사업 성공 가능성을 증가시킬 것이다.

• 건축역사연구
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• 제31권1호
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• pp.29-39
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• 2022

The remaining Joongjaesil(中齋室)-type pavilions in the eastern part of the Jirisan Mountain area showed more complex characteristics than those in the western part. The front number of kan(間) had two, three, and four kan (間) types, but the number of kan on the side was consistent with two regardless of the number of kan on the front. The pavillion is classified into 'central type', 'towards the backward type', and 'expanded by backwards type' according to the location of Joongjaesil. Joongjaesil's size, which characterizes the characteristics of Joongjaesil-type Pavilion, is related to the building's front number of kan. Front number of kan. When this space was increased by one space to four spaces, Joongjaesil must have two spaces. The pavilion with four bays in front showed the characteristics of being concentrated in Sancheong and Jinju, the eastern part of the Jirisan Mountain area. In the eastern region, many high pavilions remain, and the upper structure of the pavilion was insignificant, but the flat shape and public construction showed strong locality.

• 한국환경과학회지
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• 제13권8호
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• pp.721-731
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• 2004

The dispersion of suspended particulates in the coastal complex terrain of mountain-inland basin (city)-sea, considering their recycling was investigated using three-dimensional non-hydrostatic numerical model and lagrangian particle model (or random walk model). Convective boundary layer under synoptic scale westerly wind is developed with a thickness of about I km over the ground in the west of the mountain, while a thickness of thermal internal boundary layer (TIBL) is only confined to less than 200m along the eastern slope of the mountain, below an easterly sea breeze circulation. At the mid of the eastern slop of the mountain, westerly wind confronts easterly sea breeze, which goes to the height of 1700 m above sea level and is finally eastward return flow toward the sea. At this time, particulates floated from the ground surface of the city to the top of TIBL go along the eastern slope of the mountain in the passage of sea breeze, being away the TIBL and reach near the top of the mountain. Then those particulates disperse eastward below the height of sea-breeze circulation and widely spread out over the coastal sea. Total suspended particulate concentration near the ground surface of the city is very low. On the other hand, nighttime radiative cooling produces a shallow nocturnal surface inversion layer (NSIL) of 200 m thickness over the inland surface, but relatively thin thickness less than 100m is found near the mountain surface. As synoptic scale westerly wind should be intensified under the association of mountain wind along the eastern slope of mountain to inland plain and further combine with land-breeze from inland plain toward sea, resulting in strong wind as internal gravity waves with a hydraulic jump motion bounding up to about 1km upper level in the atmosphere in the west of the city and becoming a eastward return flow. Simultaneously, wind near the eastern coastal side of the city was moderate. Since the downward strong wind penetrated into the city, the particulate matters floated near the top of the mountain in the day also moved down along the eastern slope of the mountain, reaching the. downtown and merging in the ground surface inside the NSIL with a maximum ground level concentration of total suspended particulates (TSP) at 0300 LST. Some of them were bounded up from the ground surface to the 1km upper level and the others were forward to the coastal sea surface, showing their dispersions from the coastal NSIL toward the propagation area of internal gravity waves. On the next day at 0600 LST and 0900 LST, the dispersed particulates into the coastal sea could return to the coastal inland area under the influence of sea breeze and the recycled particulates combine with emitted ones from the ground surface, resulting in relatively high TSP concentration. Later, they float again up to the thermal internal boundary layer, following sea breeze circulation.

• Geomechanics and Engineering
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• 제22권2호
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• pp.133-142
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• 2020

The evolution of the mining-induced fracture network formed during longwall top coal caving (LTCC) has a great influence on the gas drainage, roof control, top coal recovery ratio and engineering safety of aquifers. To reveal the evolution of the mining-induced stress and fracture network formed during LTCC, the fracture network in front of the working face was observed by borehole video experiments. A discrete element model was established by the universal discrete element code (UDEC) to explore the local stress distribution. The regression relationship between the fractal dimension of the fracture network and mining stress was established. The results revealed the following: (1) The mining disturbance had the most severe impact on the borehole depth range between approximately 10 m and 25 m. (2) The distribution of fractures was related to the lithology and its integrity. The coal seam was mainly microfractures, which formed a complex fracture network. The hard rock stratum was mainly included longitudinal cracks and separated fissures. (3) Through a numerical simulation, the stress distribution in front of the mining face and the development of the fracturing of the overlying rock were obtained. There was a quadratic relationship between the fractal dimension of the fractures and the mining stress. The results obtained herein will provide a reference for engineering projects under similar geological conditions.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제25권1호
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• pp.57-81
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• 1997

Numerical prediction of nocturnal thermal high in summer of the 1995 near Taegu city located in a basin has been carried out by a non-hydrostatic numerical model over complex terrain through one-way double nesting technique in the Z following coordinate system. Under the prevailing westerly winds, vertical turbulent fluxes of momentum and heat over mountains for daytime hours are quite strong with a large magnitude of more than $120W/\textrm{m}^2$, but a small one of $5W/\textrm{m}^2$ at the surface of the basin. Convective boundary layer (CBL) is developed with a thickness of about 600m over the ground in the lee side of Mt. Hyungje, and extends to the edge of inland at the interface of land sea in the east. Sensible heat flux near the surface of the top of the mountain is $50W/\textrm{m}^2$, but its flux in the basin is almost zero. Convergence of sensible heat flux occurs from the ground surface toward the atmosphere in the lower layer, causing the layer over the mountain to be warmed up, but no convergance of the flux over the basin results from the significant mixing of air within the CBL. As horizontal transport of sensible heat flux from the top of the mountain toward over the basin results in the continuous accumulation of heat with time, enhancing air temperature at the surface of the basin, especially Taegu city to be higher than $39.3^{\circ}C$. Since latent heat fluxes are $270W/\textrm{m}^2$ near the top of the mountain and $300W/\textrm{m}^2$ along the slope of the mountain and the basin, evaporation of water vapor from the surface of the basin is much higher than one from the mountain and then, horizontal transport of latent heat flux is from the basin toward the mountain, showing relative humidity of 65 to 75% over the mountain to be much greater than 50% to 55% in the basin. At night, sensible heat fluxes have negative values of $-120W/\textrm{m}^2$ along the slope near the top of the mountain and $-50W/\textrm{m}^2$ at the surface of the basin, which indicate gain of heat from the lower atmosphere. Nighttime radiative cooling produces a shallow nocturnal surface inversion layer with a thickness of about 100m, which is much lower than common surface inversion layer, and lifts extremely heated air masses for daytime hours, namely, a warm pool of $34^{\circ}C$ to be isolated over the ground surface in the basin. As heat transfer from the warm pool in the lower atmosphere toward the ground of the basin occurs, the air near the surface of the basin does not much cool down, resulting in the persistence of high temperature at night, called nocturnal thermal high or tropical night. High relative humidity of 75% is found at the surface of the basin under the moderate wind, while slightly low relative humidity of 60% is along the eastern slope of the high mountain, due to adiabatic heating by the srong downslope wind. Air temperature near the surface of the basin with high moisture in the evening does not get lower than that during the day and the high temperature produces nocturnal warming situation.

• 대기
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• 제31권4호
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• pp.377-394
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• 2021

The recent largest forest fire in the Yeongdong region, Goseung/Okgae fires of 2019 occurred during YangGang wind event. The wind can be locally gusty and extremely dry, particularly in the complex terrain of Yeongdong. These winds can cause and/or rapidly spread wildfires, the threat of which is serious during the dry spring season. This study examines the spatial variability of the surface wind and its coupling with the upper atmospheric wind using the data during the IOP of the Gangwon Yeongdong Wind Experiments (G-WEX) conducted in 2020 and the data during YangGang wind event on 4~5 April 2019. In the case of IOPs, strong wind at the surface with a constant wind direction appears in the mountain area, and weak wind with large variability in wind direction appears from foothill to the coast in the vicinity of Gangneung region. However, in the 2019 event, strong wind at the surface with a constant wind direction appears in the entire region from the mountain to the coast, even with the stronger wind in the coast than in some part of the mountain area. The characteristics of the upper atmospheric wind related with the spatial distribution of surface wind show that during IOPs of G-WEX, a strong downdraft exists near the mountaintop in the level of about 1 to 4 km. However, in the 2019 event a strong downdraft is reinforced, when its location moves toward the coast and descends close to the ground. These downdrafts are generated by the breaking of mountain waves.