• 항공우주시스템공학회지
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• 제12권4호
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• pp.57-63
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• 2018

적외선 온도 측정 기법은 비접촉식 방법으로 모형의 표면 온도를 가시화할 수 있는 기법이다. 그러나 획득할 수 있는 결과는 2차원 온도 결과로 정량적인 결과를 획득하기에는 한계가 있다. 본 연구는 3차원 매핑 기법을 적외선 온도 측정 기법에 적용하는 것이 목표이다. 풍동 실험은 국방과학연구소에서 보유하고 있는 중형 아음속 풍동에서 수행했으며, 대상 모형은 오자이브 실린더이다. 시험 조건은 유속 20 m/s에서 80 m/s, 받음각은 $0^{\circ}{\sim}90^{\circ}$이다. 3차원 매핑 기법은 마커를 이용하여 실제 모형의 위치정보와 적외선 이미지 상의 위치 정보를 대응시키는 방법을 사용하였다. 그 결과, 모형의 박리점이 이론적인 값과 매우 일치하는 것을 확인하였다.

• 한국환경과학회지
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• 제16권4호
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• pp.399-407
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• 2007

The characteristics of meteorological conditions relevant to Asian dust (AD) outbreaks and their occurrence frequencies were analyzed in four source regions (R1 to R4) during spring months (March to May) of 1995-2002. Moreover, the concentration variations of AD (e.g., $PM_{10}$) observed in Korea were investigated during the study period. In the relationship between AD outbreaks and three meteorological parameters (i.e., air temperature, wind speed, and aridity), the largest AD outbreaks in April (${\sim}250$ observations) mostly occurred in R2 when air temperature ranging from 10.0 to $15^{\circ}C$ and surface wind speed from 7 to $9m\;s^{-1}$ were recorded. Moreover, the aridity ($\geq4$) in April was significantly high in R2 with the maximum frequency of AD outbreaks (i.e., 206 observations). On the other hand, the number (percentage) of days belonging to AD events observed in five Korean cities were found to be 116 (44%), 121 (46%), and 26 days (10%) in March, April, and May, respectively. The mean $PM_{10}$ concentrations were found to range from 150 to 220, 150 to 200, and 95 to $120{\mu}g\;m^{-3}$ in March, April, and May, respectively. Consequently, this implied that the AD events in Korea were found to be gradually frequent in early spring and to be affected from the large AD outbreaks observed in the source regions.

• 한국환경과학회지
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• 제20권4호
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• pp.465-482
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• 2011

To preserve atmospheric environment of urban areas, it needs to create urban space considering air pollution sources and natural and geographical properties such as wind circulation. According to this study could examine climate and environmental characteristics of Daegu and accordingly suggest a climate map in urban environment and an "advice map" in urban planning. The urban area(area paved with asphalt and concrete) of Daegu has increased by more than five times since 1960. In addition, the analysis of thermal environment through satellite data shows that the surface temperature between a place paved with artificial structures and a farmland shows $10{\sim}20^{\circ}C$ difference during the daytime in the summer. Regarding the parks inhibiting the heat island of a city have the small area of trees, and the road paved with concrete is wide so that they hardly serve as the source of heat absorption. As Apsan is located to the south of Daegu and Palgonsan to the north and Daegu has east high west low type, mountain wind from mountains in the south and north passes a city and delivers heat and air pollutions at night. In the west of Daegue, there is the poorest environment and industrial facilities and environmental basic facilities are mostly located, so large residential complexes that are being built around the industrial facilities as if they set up a folding screen and therefore the poor environment is increasingly worse.

• 한국환경과학회지
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• 제19권3호
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• pp.353-363
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• 2010

The most efficient measures to reduce damage from natural disasters include activities which prevent disasters in advance, decrease possibility of disasters and minimize the scale of damage. Therefore, developing of the risk assessment model is very important to reduce the natural disaster damage. This study estimated a typhoon damage which is the biggest damage scale among increased natural disasters in Korea along with climate change. The results of 3-second gust at the height of 10m level from the typhoon 'Maemi' which did considerable damage to Korean in 2003, using the wind data at the height of 700 hPa. September 12th 09 LST~13th 12 LST period by the time a typhoon Maemi approached to the Korean peninsula. This study estimate damage amount using 'Fragility curve' which is the damage probability curve about a certain wind speed of the each building component factors based on wind load estimation results by using 3-second gust. But the fragility curve is not to Korea. Therefore, we use the fragility curves to FPHLM(FDFS, 2005). The result of houses damage amount is about 11 trillion 5 million won. This values are limit the 1-story detached dwelling, $62.51\sim95.56\;m^2$ of total area. Therefore, this process is possible application to other type houses.

• Ocean and Polar Research
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• 제31권4호
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• pp.369-377
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• 2009

Performance of the Korea Ocean Research and Development Institute (KORDI) operational storm surge prediction system for the Korean coast is presented here. Results for storm surge hindcasts and forecasts calculations were analyzed. The KORDI storm surge system consists of two important components. The first component is atmospheric models, based on US Army Corps of Engineers (CE) wind model and the Weather Research and Forecasting (WRF) model, and the second components is the KORDI-storm surge model (KORDI-S). The atmospheric inputs are calculated by the CE wind model for typhoon period and by the WRF model for non-typhoon period. The KORDI-S calculates the storm surges using the atmospheric inputs and has 3-step nesting grids with the smallest horizontal resolution of ${\sim}$300 m. The system runs twice daily for a 72-hour storm surge prediction. It successfully reproduced storm surge signals around the Korean Peninsula for a selection of four major typhoons, which recorded the maximum storm surge heights ranging from 104 to 212 cm. The operational capability of this system was tested for forecasts of Typhoon Nari in 2007 and a low-pressure event on August 27, 2009. This system responded correctly to the given typhoon information for Typhoon Nari. In particular, for the low-pressure event the system warned of storm surge occurrence approximately 68 hours ahead.

• 한국대기환경학회지
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• 제25권4호
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• pp.304-315
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• 2009

Numerical simulations were carried out to understand the effect of Sea Surface Temperature (SST) spatial distribution on regional circulation. A three-dimensional non-hydrostatic atmospheric model RAMS, version 6.0, was applied to examine the impact of SST forcing on regional circulation. New Generation Sea Surface Temperature (NGSST) data were implemented to RAMS to compare the results of modeling with default SST data. Several numerical experiments have been undertaken to evaluate the effect of SST for initialization. First was the case with NGSST data (Case NG), second was the case with RAMS monthly data (Case RM) and third was the case with seasonally averaged RAMS monthly data (Case RS). Case NG showed accurate spatial distributions of SST but, the results of RM and RS were $3{\sim}4^{\circ}C$ lower than buoy observation data. By analyzing practical sea surface conditions, large difference in horizontal temperature and wind field for each run were revealed. Case RM and Case RS showed similar horizontal and vertical distributions of temperature and wind field but, Case NG estimated the intensity of sea breeze weakly and land breeze strongly. These differences were due to the difference of the temperature gradient caused by different spatial distributions of SST. Diurnal variations of temperature and wind speed for Case NG indicated great agreement with the observation data and statistics such as root mean squared error, index of agreement, regression were also better than Case RM and Case RS.

• 한국물환경학회지
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• 제25권6호
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• pp.922-934
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• 2009

The transport of contaminants and spatial variation in a deep reservoir are certainly governed by the thermal structure of the reservoir. There has been continuous efforts to utilize three-dimensional (3D) hydrodynamic and water quality models for supporting reservoir management, but the efforts to validate the models performance using extensive field data were rare. The study was aimed to evaluate a 3D hydrodynamic model, ELCOM, in Daecheong Reservoir for simulating heat fluxes and stratification processes under hydrological years of 2001, 2006, 2008, and to assess the impact of internal wave on the reservoir mixing. The model showed satisfactory performance in simulating the water temperature profiles: the absolute mean errors at R3 (Hoenam) and R4 (Dam) sites were in the range of $1.38{\sim}1.682^{\circ}C$. The evaporative and sensible heat losses through the reservoir surface were maximum during August and January, respectively. The net heat flux ($H_n$) was positive from February to September, while the stratification formed from May and continued until September. Instant vertical mixing was observed in the reservoir during strong wind events at R4, and the model reasonably reproduced the mixing events. A digital low-pass filter and zero crossing method was used to evaluate the potential impact of wind-driven internal wave on the reservoir mixing. The results indicated that most of the wind events occurred in 2001, 2006, 2008 were not enough to develop persistent internal wave and effective mixing in the reservoir. ELCOM is a suitable 3D model for supporting water quality management of the deep and stratified reservoirs.

• 한국해안해양공학회지
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• 제19권4호
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• pp.295-302
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• 2007

2006년 10월 $23{\sim}24$일 동해안 일대에서 발생한 이상 고파(高波)를 5개 지점에서 관측하고 기상청에서 제공하는 바람 자료를 함께 이용하여 고파의 특성을 분석하였다. 이번 이상 고파는 높은 너울이 동해안에 영향을 미치기 시작하는 시점에 동해상에 발달한 온대성 저기압의 영향으로 동해선풍이 지속적으로 강하게 불어서 발생하였다. 5개 관측 지점 중 가장 북쪽에 위치한 속초에서는 최대 순간풍속 63.7 m/s의 강풍과 최대 유의파고 9.69 m, 첨두주기 12.8 s의 고파가 관측되었다. 이처럼 높은 파가 발생한 이유는 강풍이 부는 동안 높은 너울이 지속적으로 유지되었고 강풍이 너울의 진행과 같은 방향으로 불어서 너울과 풍파의 중첩에 의한 파고 상승 효과가 극대화되었기 때문이다. 동해안에서는 겨울철에 이러한 돌발성 폭풍파가 발생할 가능성이 매우 높으므로 이를 고려하여 피해를 최소화하도록 대응 방침을 수립해야 할 것이다.

• 한국환경과학회지
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• 제18권7호
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• pp.721-733
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• 2009

To examine the fluctuations of aerosol number concentration with different size in the boundary layer of marine area during summer season, aerosol particles were assayed in the Ieodo Ocean Research Station, which is located 419 km southwest of Marado, the southernmost island of Korea, from 24 June to 4 July, 2008. The Laser Particle Counter (LPC) was used to measure the size of aerosol particles and NCEP/NCAR reanalysis data and sounding data were used to analyze the synoptic condition. The distribution of aerosol number concentration had a large variation from bigger particles more than 3 ${\mu}m$ in diameter to smaller particles more than 1 ${\mu}m$ in diameter with wind direction during precipitation. The aerosol number concentration decreased with increasing temperature. An increase (decrease) of small size of aerosol (0.3${\sim}$0.5 ${\mu}m$ in diameter) number concentration was induced by convergence (divergence) of the wind fields. The aerosol number concentration of bigger size more than 3 ${\mu}m$ in diameter after precipitation was removed as much as 89${\sim}$94% compared with aerosol number concentration before precipitation. It is considered that the larger aerosol particles would be more efficient for scavenging at marine boundary layer. In addition, the aerosol number concentration with divergence and convergence could be related with the occurrence and mechanism of aerosol in marine boundary layer.

• 한국작물학회지
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• 제54권2호
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• pp.210-217
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• 2009

본 연구에서 실행한 LM 벼의 화분비산 연구는 non-LM벼와 잡초성 벼의 의도치 않은 교잡은 경작지의 생태계에 문제를 야기할 기능성이 커지고 있다. 본 연구는 이를 예방하기 위한 벼의 이격거리 설정을 위하여 수행하였다. 1. 벼의 개화기간의 개화시간$(10:00{\sim}14:00)$의 주풍은 남풍이었으며, 시간대별 풍속은 $0.94{\sim}1.77$ m/s이었다. 2. 개화기는 LM벼와 Wild벼가 일치하는 기간은 8일이였으며, LM벼와 Wild벼의 최성기는 4일의 차이가 있다. 3. LM벼의 화분이 non-LM벼보다 유의하게 작게 조사되었다. 4. 화분채집량은 위가 노출된 슬라이드 글라스가 위가 덮인 슬라이드 글래스 보다 많았으며 LM벼가 Wild벼보다 비산량이 많았다. 5. 벼 화분의 비산은 오전 10시부터 오후 2시까지 대부분 이루어졌다. 6. 거리에 따른 화분비산량은 1 m까지는 급격히 감소하였으며 2 m이상에서는 서서히 감소하는 전형적인 지수함수를 나타냈으며, 3 m이상에서는 거의 발견되지 않았다.