• Title/Summary/Keyword: Coastal Mountain

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Evolution of Wind Storm over Coastal Complex Terrain (연안복합지형에서 바람폭풍의 진화)

  • Choi, Hyo;Seo, Jang-Won;Nam, Jae-Cheol
    • Journal of Environmental Science International
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    • v.11 no.9
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    • pp.865-880
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    • 2002
  • As prevailing synoptic scale westerly wind blowing over high steep Mt. Taegulyang in the west of Kangnung coastal city toward the Sea of Japan became downslope wind and easterly upslope wind combined with both valley wind and sea breeze(valley-sea breeze) also blew from the sea toward the top of the mountain, two different kinds of wind regimes confronted each other in the mid of eastern slope of the mountain and further downward motion of downlsope wind along the eastern slope of the mountain should be prohibited by the upslope wind. Then, the upslope wind away from the eastern slope of the mountain went up to 1700m height over the ground, becoming an easterly return flow in the upper level of the sea. Two kinds of circulations were detected with a small one in the coastal sea and a large one from the coast toward the open sea. Convective boundary layer was developed with a thickness of about 1km over the ground in the upwind side of the mountain in the west, while a thickness of thermal internal boundary layer(TIBL) form the coast along the eastern slope of the mountain was only confined to less than 200m. After sunset, under no prohibition of upslope wind, westerly downslope wind blew from the top of the mountain toward the coastal basin and the downslope wind should be intensified by both mountain wind and land breeze(mountain-land breeze) induced by nighttime radiative cooling of the ground surfaces, resulting in the formation of downslope wind storm. The wind storm caused the development of internal gravity waves with hydraulic jump motion bounding up toward the upper level of the sea in the coastal plain and relatively moderate wind on the sea.

Tropical Night (Nocturnal Thermal High) in the Mountainous Coastal City

  • Choi, Hyo
    • Journal of Environmental Science International
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    • v.13 no.11
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    • pp.965-985
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    • 2004
  • The investigation of driving mechanism for the formation of tropical night in the coastal region, defined as persistent high air temperature over than 25$^{\circ}C$ at night was carried out from August 14 through 15, 1995. Convective boundary layer (CBL) of a 1 km depth with big turbulent vertical diffusion coefficients is developed over the ground surface of the inland basin in the west of the mountain and near the top of the mountain, while a depth of thermal internal boundary layer (TIBL) like CBL shrunken by relatively cool sea breeze starting at 100 km off the eastern sea is less than 150 m from the coast along the eastern slope of the mountain. The TIBL extends up to the height of 1500 m parallel to upslope wind combined with valley wind and easterly sea breeze from the sea. As sensible heat flux convergences between the surface and lower atmosphere both at the top of mountain and the inland coast are much greater than on the coastal sea, sensible heat flux should be accumulated inside both the TIBL and the CBL near the mountain top and then, accumulated sensible heat flux under the influence of sea breeze circulation combined with easterly sea breeze from sea to inland and uplifted valley wind from inland to the mountain top returning down toward the eastern coastal sea surface should be transported into the coast, resulting in high air temperatures near the coastal inland. Under nighttime cooling of ground surface after sunset, mountain wind causes the daytime existed westerly wind to be an intensified westerly downslope wind and land breeze further induces it to be strong offshore wind. No sensible heat flux divergence or very small flux divergence occurs in the coast, but the flux divergences are much greater on the top of the mountain and along its eastern slope than on the coastal inland and sea surfaces. Thus, less cooling down of the coastal surface than the mountain surface and sensible heat transfer from warm pool over the coast into the coastal surface produce nocturnal high air temperature on the coastal inland surfaces, which is not much changed from daytime ones, resulting in the persistence of tropical night (nocturnal thermal high) until the early in the morning.

Recycling of Suspended Particulates by Atmospheric Boundary Depth and Coastal Circulation (대기경계층과 연안순환에 의한 부유입자의 재순환)

  • Choe, Hyo
    • Journal of Environmental Science International
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    • v.13 no.8
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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.

Orographic and Ocean Effects Associated with a Heavy Snowfall Event over Yeongdong Region (영동지역 겨울철 강수와 연관된 산악효과와 해양효과)

  • Cho, Kuh-Hee;Kwon, Tae-Young
    • Atmosphere
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    • v.22 no.1
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    • pp.57-71
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    • 2012
  • Influences of orographic and ocean effect, which depend on the detailed geographic characteristics, upon winter time (December-February) precipitation in the Yeongdong region are investigated. Most of precipitation events in the Yeongdong region during the wintertime are associated with moist northeasterly (coming from the northeast direction) winds and also the spatial distribution of precipitation shows a great difference between Mountain area (Daegwallyeong) and Coastal area (Gangneung). The linear correlation coefficient between the meteorological variables obtained from NCEP/NCAR Reanalysis Data and precipitation amount for each precipitation type is calculated. Mountain type precipitation is dominated by northeasterly wind speed of the low level (1000 hPa and 925 hPa) and characterized with more precipitation in mountain area than coastal area. However, Coastal type precipitation is affected by temperature difference between ocean and atmosphere, and characterized with more precipitation in coastal area than mountain area. The results are summarized as follows; In the case of mountain type precipitation, the correlation coefficient between wind speed at 1000 hPa (925 hPa) and precipitation amount at Daegwallyeong is 0.60 (0.61). The correlation is statistical significant at 1% level. In the case of coastal type precipitation, the correlation coefficient of temperature difference between ocean and 925 hPa (850 hPa) over the East sea area and precipitation amount at Gangneung is 0.33 (0.34). As for the mountain type precipitation, a detailed analysis was conducted in order to verify the relationship between precipitation amount at Daegwallyeong and low level wind speed data from wind profiler in Gangneung and Buoy in the East Sea. The results also show the similar behavior. This result indicates that mountain type precipitation in the Yeongdong region is closely related with easterly wind speed. Thus, the statistical analysis of the few selected meteorological variables can be a good indicator to estimate the precipitation totals in the Yeongdong region in winter time.

Numerical Prediction on Snowfall Intensity in the Mountainous Coastal Region

  • Choi, Hyo;Lee, Han-Se;Kim, Tae-Kook;Choi, Doo-Sun
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2003.11a
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    • pp.89-94
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    • 2003
  • The formation of a severe snow storm occurred in the mountainous coastal region near Mt. Taegualyang and Kangnung city in the eastern part of Korea was investigate from 0900LST, December 7 through 9, 2002, using MM5 model. As synoptic scale easterly wind induced a great amount of moisture from the East Sea into the inland coastal region and sea-breeze further induced more moisture from the basin toward the top of the mountain side. The lifted moisture toward the mountain top was cooled down along the eastern slope of the mountain and near the mid of the mountain the moisture was much cooled down with relative humidity of 100% under the air temperature below $O^{\circ}C$, resulting in the formation of snow. Relative humidity of 100% generally occurred at the 5km away from the coast toward the inland mountain and the band of 100% RH was parallel to the coastal line. The 100% band coincided with minimum air temperature band and line.

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Characteristics of Atmospheric Circulation in Sokcho Coast (속초연안에서 대기순환의 특성)

  • Choi Hyo
    • Journal of Environmental Science International
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    • v.14 no.1
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    • pp.41-51
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    • 2005
  • Using three-dimensional non-hydrostatical numerical model with one way double nesting technique, atmo­spheric circulation in the mountainous coastal region in summer was investigated from August 13 through 15, 1995. During the day, synoptic westerly wind blows over Mt. Mishrung in the west of a coastal city, Sokcho toward the East Sea, while simultaneously, easterly upslope wind combined with both valley wind from plain (coast) toward mountain and sea-breeze from sea toward inland coast blows toward the top of the mountain. Two different directional wind systems confront each other in the mid of eastern slope of the mountain and the upslope wind goes up to the height over 2 km, becoming an easterly return flow in the upper level over the sea and making sea-breeze front with two kinds of sea-breeze circulations of a small one in the coast and a large one in the open sea. Convective boundary layer is developed with a thickness of about 1km over the ground in the upwind side of the mountain in the west and a thickness of thermal internal boundary layer from the coast along the eastern slope of the mountain is only confined to less than 200 m. On the other hand, after sunset, no prohibition of upslope wind generated during the day and downward wind combined with mountain wind from mountain towardplain and land-breeze from land toward under nocturnal radiative cooling of the ground surfaces should intensify westerly downslope wind, resulting in the formation of wind storm. As the wind storm moving down along the eastern slop causes the development of internal gravity waves with hydraulic jump motion in the coast, bounding up toward the upper level of the coastal sea, atmospheric circulation with both onshore and offshore winds like sea-breeze circulation forms in the coastal sea within 70 km until midnight and after that, westerly wind prevails in the coast and open seas.

Feasibility study of wind power generation considering the topographical characteristics of Korea (우리나라 지형특성을 고려한 풍력발전 타당성 연구)

  • Moon, Chae-Joo;Cheang, Eui-Heang;Shim, Kwan-Shik;Jung, Kwen-Sung;Chang, Young-Hak
    • Journal of the Korean Solar Energy Society
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    • v.28 no.6
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    • pp.24-32
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    • 2008
  • This paper discussed the Feasibility study of wind power generation considering the topographical characteristics of Korea. In order to estimate the exact generation of wind power plants, we analyzed and compared wind resources in mountain areas and plain areas by introducing not only wind speed, the most important variable, but also wind distribution and wind standard deviation that can reflect the influence of landform sufficiently. According to the results of this study, generation was almost the same at wind power plants installed in southwestern coastal areas where wind speed was low as at those installed in mountain areas in Gangwondo where wind speed was high. This demonstrates that the shape parameter of wind distribution is low due to the characteristics of mountain areas, and the standard deviation of wind speed is large due to the effect of mountain winds, therefore, actual generation compared to southwestern coastal areas is almost similar in mountain areas even though wind speed is high.

Statistical Verification of Precipitation Forecasts from MM5 for Heavy Snowfall Events in Yeongdong Region (영동대설 사례에 대한 MM5 강수량 모의의 통계적 검증)

  • Lee, Jeong-Soon;Kwon, Tae-Yong;Kim, Deok-Rae
    • Atmosphere
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    • v.16 no.2
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    • pp.125-139
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    • 2006
  • Precipitation forecasts from MM5 have been verified for the period 1989-2001 over Yeongdong region to show a tendency of model forecast. We select 57 events which are related with the heavy snowfall in Yeongdong region. They are classified into three precipitation types; mountain type, cold-coastal type, and warm type. The threat score (TS), the probability of detection (POD), and the false-alarm rate (FAR) are computed for categorical verification and the mean squared error (MSE) is also computed for scalar accuracy measures. In the case of POD, warm, mountain, and cold-coastal precipitation type are 0.71, 0.69, and 0.55 in turn, respectively. In aspect of quantitative verification, mountain and cold-coastal type are relatively well matched between forecasts and observations, while for warm type MM5 tends to overestimate precipitation. There are 12 events for the POD below 0.2, mountain, cold-coastal, warm type are 2, 7, 3 events, respectively. Most of their precipitation are distributed over the East Sea nearby Yeongdong region. These events are also shown when there are no or very weak easterlies in the lower troposphere. Even in the case that we use high resolution sea surface temperature (about 18 km) for the boundary condition, there are not much changes in the wind direction to compare that with low resolution sea surface temperature (about 100 km).

Landscape Characteristics of Mountain Villages Recognized by Residents - Focusing on Importance-Performance Analysis - (주민들이 인식하는 산촌의 경관 유형 특성 - IPA 분석을 중심으로 -)

  • Ko, Arang;Kim, Young Jin;Kim, Seong Hak;Kim, Ye Ji
    • Journal of Korean Society of Rural Planning
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    • v.26 no.2
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    • pp.1-12
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    • 2020
  • This study aimed to define characteristics of mountain village landscapes perceived by locals to sustainably preserve and manage mountain village landscapes. We selected landscape resources of mountain villages by reviewing previous studies and conducting field surveys and surveyed mountain villages' locals to investigate the characteristics of their perceptions of the mountain village landscapes. The surveys were conducted from March to October 2019, in the form of 1:1 questionnaire survey. In consequence, highly reliable 150 responses were analyzed. IPA method(Revised Importance-Performance Analysis) was used in the analysis. It is found that, in landscapes, the first quadrant is 'Cultivated land, Forest', the second quadrant is 'Coastal, Forestry and Agriculture Facility', the third quadrant is 'Forest Service·Profitable Facility, Settlement, History and Culture', and the fourth quadrant is 'Riparian, Street'. In conclusion, locals of mountain villages are perceiving the mountain village landscapes based on their livelihoods and daily lives, and the mountain village landscapes are closely related to their lives. The results of this study are expected to be utilized as fundamental resources in establishing policies regarding sustainable conservation and management of mountain village landscapes which led by locals.

A Study on the Dispersion of Air Pollutants in Local Circulation of Mesoscale (중규모 국지 순환에서 대기 오염 물질의 확산에 관한 연구)

  • 이화운;오은주
    • Journal of Environmental Science International
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    • v.3 no.1
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    • pp.39-47
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    • 1994
  • Dispersion characteristics of air pollutants in the mountainous coastal area are investigated in considering with the mesoscale local circulations using a two dimensional numerical model with two kinds of topograpy of 500m and 300m. In the model, land-sea breezes and mountain-valley wind are mainly considered under the condition of the absence of large scale prevailing flow in the circulation analysis, and the pollutants dispersion is traced by the Lagrangian methods. According to the results, the wind velocity is affected by topography and is stronger in the case of 500m height mountain than that of 300m, the Pollutants that source is near the coast transported over the mountain and dispersed to behind inland area. It is classified that the topography change control affects the wind velocity and the circulations. The pollutants that source is different transported and concentrated to behind inland and/or diffused to the sea area by the combination of the wind system with topographic changes. The results can be applied to the air pollution control with the arrangement design of industrial area and the planning of coastal developments.

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