• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.97-109
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• 2007

Vertical distribution and optical properties of atmospheric aerosols above the Korean peninsula are quite important to estimate effects of aerosol on atmospheric environment and regional radiative forcing. For the first time in Korea, vertical microphysical properties of atmospheric aerosol obtained by inversion algorithm were analyzed based on optical data of multi-wavelength Raman lidar system developed by the Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST). Data collected on 14 June 2004 at Gwangju ($35.10^{\circ}N,\;126.53^{\circ}E$) and 27 May 2005 at Anmyeon island ($36.32^{\circ}N,\;126.19^{\circ}E$) were used as raw optical data for inversion algorithm. Siberian forest fire smoke and local originated haze were observed above and within the height of PBL, respectively on 14 June 2004 according to NOAA/Hysplit backstrajectory analysis. The inversion of lidar optical data resulted in particle effective radii around $0.31{\sim}0.33{\mu}m$, single scattering albedo between $0.964{\sim}0.977$ at 532 nm in PBL and effective radii of $0.27{\mu}m$ and single scattering albedo between $0.923{\sim}0.924$ above PBL. In the case on 27 May 2005, biomass burning from east China was a main source of aerosol plume. The inversion results of the data on 27 May 2005 were found to be particle effective radii between $0.23{\sim}0.24{\mu}m$, single scattering albedo around $0.924{\sim}0.929$ at 532 nm. Additionally, the inversion values were well matched with those of Sun/sky radiometer in measurement period.

• The Korean Journal of Ecology
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• v.18 no.3
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• pp.333-340
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• 1995

This study aims to examine how the amount of sample and changes in combustible temperature of living branches and leaves treated with high temperature are associated with combustible time of two coniferous trees, Pinus rigida (R) and Larix leptolepis (L), which are the main victims of forest fire. During the first thirty minutes at $80^{\circ}C$, moisture content of R was higher than that of L by 12%, but after four hours, the moisture content was both lowered by 4~5% and turned to highly combustible leaves. With living leaves, the maximal combustible temperature, regardless of heating temperature, turned out to be higher than normal temperature by $67~140^{\circ}C$, and that with living branches, it was higher by $113~207^{\circ}C$. Also, with living leaves (R, L), the duration time of combustion was as follows: 605, 906 seconds at $400^{\circ}C$ and 76, 227 seconds at $600^{\circ}C$, respectively. Concerning the relation between the amount of burnt fuel and maximal temperature, the more the former was, the higher the latter. The total amounts of combustion heat of living branches and living leaves were 1, 121 Cal (20.8%) and 1, 137 Cal (21.4%), respectively. The total amount of combustion heat increased in proportion to the amount of consumed fuel: 100 g of living leaves and branches gave rise to 128 Cal, whereas 300 g did 556 Cal, that was more than three times.

• The Korean Journal of Ecology
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• v.22 no.6
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• pp.325-335
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• 1999

Empetrum nigrum dominant community or Rhododendron mucronulatum and R. yedoense var. poukhanense dominant shrub community are developing above l,500m on Mt. Halla in Cheju Island, Korea. These communities were formed as a result of the forest of Abies koreana regression by grazing or erosion over a long period of time. This study was conducted using the phytosociological method and it clarified the floristic composition of the community in Cheju Island by comparing with a similar community in Japan. Also this study interpreted the development data of these communities and considered community succession. As a result of our interpretation, shrub community of Cheju Island is recognized as two associations, Festuco obinae-Empetretum nigrum ass. nov and Rhododendretum mucronulatum ass. nov. Each association of Cheju Island is composed of endemic species of Cheju Island. related to the Korean peninsula and to Japan. The two associations are divided into 8 sub-units but each community development has been created with longtime grazing and prescribed fire. Maybe the location stability by stoppage of interference and grazing will process community transition Quickly. Comparing the shrub communities of Cheju Island with Maianthemo-Rhododendretum in Kyushu, Japan, which is close geographically, both areas have the species of Miscanthetea sinesis and Ericaceae in common. But Cheju Island has more abundant species and has higher ratio of appearance of alpine plants. The shrub communities of Cheju Island and Kyushu. Japan are identified as having a different rank over Alliance.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.298-301
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• 2007

Vertical distribution and optical properties of atmospheric aerosols above the Korean peninsula are quite important to estimate effects of aerosol on atmospheric environment and regional radiative forcing. For the first time in Korea, vertical microphysical properties of atmospheric aerosol obtained by inversion algorithm were analyzed based on optical data of multi-wavelength Raman lidar system developed by the Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST). Data collected on 14 June 2004 at Gwangju ($35.10^{\circ}N$, $126.53^{\circ}E$) and 27 May 2005 at Anmyeon island ($36.32^{\circ}N$, $126.19^{\circ}E$) were used as raw optical data for inversion algorithm. Siberian forest fire smoke and local originated haze were observed above and within the height of PBL, respectively on 14 June 2004 according to NOAA/Hysplit backstrajectory analysis. The inversion of lidar optical data resulted in particle effective radii around 0.32 ${\mu}m$, single scattering albedo between 0.97 at 532 nm in PBL and effective radii of 0.27 ${\mu}m$ and single scattering albedo of 0.92 above PBL. In the case on 27 May 2005, biomass burning from east China was a main source of aerosol plume. The inversion results of the data on 27 May 2005 were found to be particle effective radii between 0.24 ${\mu}m$, single scattering albedo around 0.91 at 532 nm. Additionally, the inversion values were well matched with those of Sun/sky radiometer in measurement period.

• Atmosphere
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• v.20 no.2
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• pp.187-194
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• 2010

We estimate the economic benefit of weather modification (precipitation enhancement and fog dissipation) by assuming its operation for the considered regions. Based on the statistical data, the economic benefit of the virtually operational precipitation enhancement experiments for the Andong and Imha basins, where the natural precipitation is relatively lack in South Korea, is calculated 348 for the water resources, 22,458 for forest fire prevention, and 28,458 million won/year for the drought relief. The benefit of the fog dissipation operation for the Incheon International Airport is estimated 7,365 million won/year for the flight delay due to fog. The calculated ratio of benefit to cost for precipitation enhancement operation for the basins is 14.07, which is comparable to that conducted in other countries.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1433-1435
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• 2003

Very decisive progress was made in advancing fundamental POL-IN-SAR theory and algorithm development during the past decade. This was accomplished with the aid of airborne & shuttle platforms supporting single -to-multi-band multi-modal POL-SAR and also some POL-IN-SAR sensor systems, which will be compared and assessed with the aim of establishing the hitherto not completed but required missions such as tomographic and holographic imaging. Because the operation of airborne test-beds is extremely expensive, aircraft platforms are not suited for routine monitoring missions which is better accomplished with the use drones or UAVs. Such unmanned aerial vehicles were developed for defense applications, however lacking the sophistic ation of implementing advanced forefront POL-IN-SAR technology. This shortcoming will be thoroughly scrutinized resulting in the finding that we do now need to develop most rapidly POL-IN-SAR drone-platform technology especially for environmental stress-change monitoring with a great variance of applications beginning with flood, bush/forest-fire to tectonic-stress (earth-quake to volcanic eruptions) for real-short-time hazard mitigation. However, for routine global monitoring purposes of the terrestrial covers neither airborne sensor implementation - aircraft and/or drones - are sufficient; and there -fore multi-modal and multi-band space-borne POL-IN-SAR space-shuttle and satellite sensor technology needs to be further advanced at a much more rapid phase. The existing ENVISAT with the forthcoming ALOSPALSAR, RADARSAT-2, and the TERRASAT will be compared, demonstrating that at this phase of development the fully polarimetric and polarimetric-interferometric modes of operation must be viewed and treated as preliminary algorithm verification support modes and at this phase of development are still not to be viewed as routine modes.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.7-7
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• 2016

인도네시아 산불에 의한 연무는 동남아시아 인접한 국가들에 있어서 심각한 환경문제 중 하나이다. 국제적으로 심각한 문제를 야기하는 인도네시아의 산불은 건조기에 강수량이 적게 내리는 극심한 가뭄 조건에서 발생한다. 건조기 강수량을 모니터링 하는 것은 산불 발생 가능성을 예측하기 위해 중요하지만 산불을 사전에 예방하고 영향을 최소화하기에는 부족하다. 따라서 산불에 대한 선제적 사전예방을 위해서는 수개월의 선행예측 기간을 갖는 조기경보 시스템이 절실하다. 따라서 본 연구는 인도네시아 산불에 대한 선제적 대응을 위한 강수량 예측시스템을 개발하고 예측성을 평가하여 동남아시아 지역의 화재 연무 조기경보 시스템의 시제품(Prototype)을 개발하는데 있다. 강수량 예측을 위해서 APEC 기후센터의 계절예측정보의 활용 정도에 따라서 4가지 서로 다른 방법을 통합하여 사용하였다. 예측정보 기반의 방법들로는 대상지역의 강수량 예측을 위해서 대상 지역 상공의 계절예측 강수자료를 보정을 통해 직접적으로 사용하는 SBC (Simple Bias Correction) 방법과 대상 지역 상공의 강수 예측자료를 사용하는 대신에 지역 강수량과 높은 상관 관계를 보이는 다른 지역의 대리변수를 예측인자로 사용하는 MWR (Moving Window Regression) 방법이 있다. 또한 예측자료의 사용 없이 과거자료 기반의 기후지수(Climate Index) 중에서 지체시간을 고려하여 지역 강수량과 높은 상관관계를 갖는 경우 예측에 활용하는 관측자료 기반의 CIR (Climate Index Regression) 방법과 예측기반 MWR과 관측기반의 CIR 방법에서 선정된 예측인자를 동시에 활용하는 ITR (Integrated Time Regression) 방법이 사용되었다. 장기 강수량 예측은 보르네오 섬의 4개 지역에서 3개월 이하의 선행예측기간에 대하여 0.5 이상의 TCC (Temporal Correlation Coefficient)의 값을 보여 양호한 예측성능을 보였다. 예측된 강수량 자료는 위성기반 관측 강수량 및 관측 탄소 배출량 관계에서 결정된 강수량의 임계값과의 비교를 통해 산불발생 가능성으로 환산하였다. 개발된 조기경보 시스템은 산불 발생에 가장 취약한 해당지역의 건조기(8월~10월) 강수량을 4월부터 예측해 산불 연무에 대한 조기경보를 수행한다. 개발된 화재 연무조기경보 시스템은 지속적인 개선을 통해 현장 실효성을 높여 동남아국가 정부의 화재 및 산림관리자들에게 보급함으로써 동남아의 화재 연무로 인한 환경문제 해결에 기여할 수 있으리라 판단된다.

• Atmosphere
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• v.31 no.4
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.63-73
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• 2021

This paper presents a algorithm for automatic target recognition robust to the influence of the flame in order to track the target by EOTS(Electro-Optical Targeting System) equipped on UAV(Unmanned Aerial Vehicle) when there is aerial target or marine target with flame at the same time. The proposed method converts infrared images of targets and flames into a gradient vector field, and applies each gradient magnitude to a polynomial curve fitting technique to extract polynomial coefficients, and learns them in a shallow neural network model to automatically recognize targets and flames. The performance of the proposed technique was confirmed by utilizing the various infrared image database of the target and flame. Using this algorithm, it can be applied to areas where collision avoidance, forest fire detection, automatic detection and recognition of targets in the air and sea during automatic flight of unmanned aircraft.

• Applied Chemistry for Engineering
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• v.22 no.6
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• pp.636-641
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• 2011

Since the mid-1990s, the number of fires continue to increase and the size has been also larger. However, the pyrolysis and combustion characteristics of the various species of the medium such as fallen leaves, herbaceous plants, conifers and broadleaf trees have scarcely been studied. In this paper, we investigate the pyrolysis and combustion of the typical domestic needle-leaf tree of Pinus densiflora and thinning-out tree by thermogravimetric analysis (TGA). Pinus densiflora was ignited at $200^{\circ}C$ and pyrolysis from $230^{\circ}C$. In case of thinning-out tree was ignited and pyrolysis at $180^{\circ}C$ and $205^{\circ}C$, respectively. The values of activation energy for pyrolysis were increased as the conversion efficiency increasing from 10% to 80%, whereas the values was decreased during combustion.