• 대기
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• 제31권4호
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• pp.433-443
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• 2021

The wind speed and wind direction in Yeongdong are one of the crucial meteorological factors for forecasting snowfall in this area. To improve the snowfall forecast in Yeongdong region, Yeongdong Extreme Snowfall-Windstorm Experiment, YES-WEX was designed. We examined the wind field variation simulated with Local Data Assimilation and Prediction System (LDAPS) using observed wind field during YES-WEX period. The simulated wind speed was overestimated over the East Sea and especially 2 to 4 times in the coastal line. The vertical wind in Yeongdong region, which is a crucial factor in the snowfall forecast, was not well simulated at the low level (850 hPa~1000 hPa) until 12 hours before the forecast. The snowfall distribution was also not accurately simulated. Three hours after the snowfall on the East Sea coast was observed, the snowfall was simulated. To improve the forecast accuracy of snowfall in Yeongdong region, it is important to understand the weather conditions using the observed and simulated data. In the future, data in the northern part of the East Sea and the mountain slope of Taebaek observed from the meteorological aircraft, ship, and drone would help in understanding the snowfall phenomenon and improving forecasts.

• 한국태양에너지학회 논문집
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• 제36권1호
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• pp.63-73
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• 2016

How effectively a wind farm captures high market prices can greatly influence a wind farm's viability. This research identifies and creates an understanding of the effects that result in various capture prices (average revenue earned per unit of generation) that can be seen among different wind farms, in the current and future competitive SMP (System Marginal Price) market in South Korea. Through the use of a neural network to simulate changes in SMP caused by increased renewables, based on the Korea Institute of Energy Research's extensive wind resource database for South Korea, the variances in current and future capture prices are modelled and analyzed for both onshore and offshore wind power generation. Simulation results shows a spread in capture price of 5.5% for the year 2035 that depends on both a locations wind characteristics and the generations' correlation with other wind power generation. Wind characteristics include the generations' correlation with SMP price, diurnal profile shape, and capacity factor. The wind revenue cannibalization effect reduces the capture price obtained by wind power generation that is located close to a substantial amount of other wind power generation. In onshore locations wind characteristics can differ significantly/ Hence it is recommended that possible wind development sites have suitable diurnal profiles that effectively capture high SMP prices. Also, as increasing wind power capacity becomes installed in South Korea, it is recommended that wind power generation be located in regions far from the expected wind power generation 'hotspots' in the future. Hence, a suitable site along the east mountain ridges of South Korea is predicted to be extremely effective in attaining high SMP capture prices. Attention to these factors will increase the revenues obtained by wind power generation in a competitive electricity market.

• 환경영향평가
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• 제20권3호
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• pp.337-348
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• 2011

Urban environmental problem became one of major issues during its urbanization processes. Environmental impacts are assessed during recent urban planning and development. Though the environmental impact assessment considers meteorological impact as a minor component, changes in wind environment during development can largely affect the distribution pattern of air temperature, humidity, and pollutants. Impact assessment of local wind is, therefore, a major element for impact assessment prior to any other meteorological impact assessment. Computational Fluid Dynamics (CFD) models are utilized in various fields such as in wind field assessment during a construction of a new building and in post analysis of a fire event over a mountain. CFD models require specially formatted input data and produce specific output files, which can be analyzed using special programs. CFD's huge requirement in computing power is another hurdle in practical use. In this study, a CFD model and related software processors were automated and integrated as a microscale wind environmental impact assessment system. A supercomputer system was used to reduce the running hours of the model. Input data processor ingests development plans in CAD or GIS formatted files and produces input data files for the CFD model. Output data processor produces various analytical graphs upon user requests. The system was used in assessing the impacts of a new building near an observatory on wind fields and showed the changes by the construction visually and quantitatively. The microscale wind assessment system will evolve, of course, incorporating new improvement of the models and processors. Nevertheless the framework suggested here can be utilized as a basic system for the assessment.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제23권1호
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• pp.18-33
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• 1995

동쪽 연안지역에서 큰 경사를 갖인 산맥위를 흘러가는 종관규모의 서풍하에서 내부 중력파와 같은 강한 하강폭풍이 산의 후면에서 발생되어 진다. 주간에 해양에서 내륙으로 향하는 중규모의 열적 강화에 의해 유도되는 해풍순환이 동쪽으로 향하는 내부중력파에 기인하여 연안의 앞바다까지만 국한된다. 따라서 연안해 근처의 표층풍은 외해나 내륙의 위치에서보다 상대적으로 더 약하다. 명백하게 서풍의 내부중력파순환파 해면 근처에서 동풍 및 상층에서 서풍을 갖는 해풍순환과 같은 두개의 상이한 종류의 대기순환이 뚜렷하게 나타났다. 이런 상황에서 강릉시에서의 대기오염물질은 반대 방향의 두개의 상이한 순환에 의해 갇히게 되고 부유분진과 오존의 고농도가 초래되었다. 야간에 육지에서 연안해로 향하는 중규모의 육풍은 기존의 동쪽으로 향하는 하강풍과 협력하여 연안지역에서 서풍의 더욱 강화를 유도할 수 있었다. 산쪽에서 연안해로 향하여 부는 강한 표층풍에 의해 조절되는 부유분진의 농도는 추간의 경우보다 야간에 비교적 더 높았으며, 상층대기로 부터 지표면으로 오존의 하양수송에 기인하여 오존의 농도가 주간보다 야간에 매우 높았다. 결과로 바람폭풍하의 산악연안지역에서 대기오염농도는 바람푹풍 전.후보다 더 높았다.

• 대기
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• 제16권2호
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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).

• 한국안전학회지
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• 제27권3호
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• pp.176-181
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• 2012

In this research the 2009 spring occurred during forest fire ImSil and research destination GyeongJu has been selected. Research in the field of the target time exploratory Boundary Data through after air photos, satellite photos and topographic map by using the combustion area was calculated. 2009 March 1-forest fire occurs on the day of the weather information and weather changes wildfire in the check in any affected. Study research destination of combustion is ImSil 161 ha, GyeongJu 270.93 ha. The impact of the weather-temperature dry weather forest fires this favorable situation to occur and the wind directions and the spread of the mountain wind speed was less impact has no arguments.

• 한국대기환경학회지
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• 제25권4호
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• pp.289-303
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• 2009

The chemical and meteorological effects on the concentration variations of ozone ($O_3$) were evaluated based on the intensive air quality measurement (5 pollutants and aromatic volatile organic compounds (AVOCs)) in and out-side an urban valley during spring and summer of 2006. The 5 pollutants measured in the study area include $O_3$, $NO_2$, NO, $PM_{10}$, and CO; the AVOCs include benzene (BEN), toluene (TOL), ethylbenzene (EB), m,p-xylene (MPX), and o-xylene (OX). For the purpose of this study, study areas were classified into two categories: valley area (VA) with a semi-closed topography covering a number of industrial complex, public building, and mountains and non-valley area (NVA) surrounding the suburban and residential areas. In general, the mean concentration levels of most pollutants (except for $PM_{10}$) in the VA were higher than those in the NVA. It was found that the average $O_3$ increase in the VA during spring might result from the combined effects such as the photochemical production from diverse anthropogenic sources and the $O_3$ accumulation due to geographical features (e.g., the semi-closed topography) and wind conditions (e.g., a low wind speed). In addition, the nocturnal $O_3$ increase in the VA during spring was primarily caused by local wind conditions (e.g., mountain and valley winds) with the low wind speed (approximately $1{\sim}2\;m\;s^{-1}$). On the other hand, the $O_3$ difference between the two areas during summer might be because of the photo-chemical production with the $O_3$ precursors (especially the AVOCs) rather than the contribution of wind conditions.

• 대기
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• 제17권4호
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• pp.393-405
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• 2007

Simulation results of WRF for the case of typhoon 'Rusa' were analyzed, comparing with observed data especially forjavascript:confirm_mark('abe', '1'); the Gangneung area around to examine its ability in numerical simulation. From the hourly precipitation time series, two peaks were found at Gangneung and Daegwallyeong, while only one peak was found from those of inland regions else. Especially, for the Yeongdong region, the first peak was directly related to spiral bands generated in front of the typhoon. Convective cells that were developed within the spiral bands moved to the eastern coastal area from the sea so that local heavy rainfall occurred in the Yeongdong region. The second peak was mainly related to the accompanying rain band of typhoon itself, topographic effect and the convergence near Gangneung area. Precipitation in Gangneung was simulated as much as about 30% of observed one. The main reason of this result came from a poor representation of wind directions in Gangneung area of WRF model. Observed wind direction was northwesterly but simulated one was nearly easterly in the area. This might shift a local heavy rainfall area downstream to the mountain area rather than the coastal area.

• Journal of Korean Society for Atmospheric Environment
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• 제21권E3호
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• pp.107-113
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• 2005

Using a sampling device of our own making, airborne pollen has been monitored in Kyoto, Japan from the middle of February to the end of May 2004. From the morphological analysis of pollen grains by Scanning Electron Microscope (SEM), it was possible to identify some pollen types like Cryptomeria, Pine, Alder, Cyclobalanopsis, Chamaecyparis, and Equisetum. Daily average airborne pollen counts show strong variations from the day to day which makes the appropriate daily forecasts that could be of practical use for patients difficult. Diurnal variation of airborne pollen grains at our local sampling site is very irregular and shows no similarity between pollen types. The highest concentrations of Cryptomeria and Alder pollens in the south -west wind directions might be attributed to the airborne pollen transport, while the increase in Pine pollen grain in the southern wind direction was probably due to the local spread. Prevailing wind direction (SW) during the pollinating periods of Cryptomeria and Alder pollens could suggest a long-distance transport from a distant mountain.

• 대기
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• 제19권4호
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• pp.331-344
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• 2009

A sensitivity study has been performed using ARPS (Advanced Regional Prediction System) version 5.2.10 in a downslope windstorm case of 12-13 February 2006. The purpose of this study was to find out the role of the inversion layer of temperature mainly in relation to the strength of the downslope winds over the Yeongdong region located downstream of the Taebaek mountains. Under the conditions of N (Brunt-$V{\ddot{a}}is{\ddot{a}}la$ frequency)=0.008 and N=0.016, the effects of the presence of the inversion layer, its variation of height of the layer, and the depth of the layer were identified. The sensitivity experiments suggested that the inversion layer effected the downstream wind speed of the mountains under both conditions of N=0.008 and N=0.016, and notably when the inversion layer was located near the mountain crest the downstream wind speed of the mountains was strong (~ $27ms^{-1}$) only under the condition of N=0.016. In addition, when the atmosphere was rather stable (N=0.016) and the depth of the layer was relatively thin (765 m) the downstream wind speed of the mountains was the strongest (~ $30ms^{-1}$) among the sensitivity experiments.