• 한국기후변화학회지
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• 제7권4호
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• pp.433-442
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• 2016

In this study, we examine future changes in surface radiation associated with cloud amount and aerosol emission over East Asia. Data in this study is HadGEM2-CC (Hadley Centre Global Environmental Model version 2, Carbon Cycle) simulations of the Representative Concentration Pathways (RCPs) 2.6/4.5/8.5. Results show that temperature and precipitation increase with rising of the atmosphere $CO_2$. At the end of $21^{st}$ century (2070~2099) relative to the end of $20^{st}$ century (1981~2005), changes in temperature and precipitation rate are expected to increase by $+1.85^{\circ}C/+6.6%$ for RCP2.6, $+3.09^{\circ}C/+8.5%$ for RCP4.5, $+5.49^{\circ}C/10%$ for RCP8.5. The warming results from increasing Net Down Surface Long Wave Radiation Flux (LW) and Net Down Surface Short Wave Radiation Flux (SW) as well. SW change increases mainly from reduced total Aerosol Optical Depth (AOD) and low-level cloud amount. LW change is associated with increasing of atmospheric $CO_2$ and total cloud amount, since increasing cloud amounts are related to absorb LW radiation and remit the energy toward the surface. The enhancement of precipitation is attributed by increasing of high-level cloud amount. Such climate conditions are favorable for vegetation growth and extension. Expansion of C3 grass and shrub is distinct over East Asia, inducing large latent heat flux increment.

• 환경영향평가
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• 제28권4호
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• pp.413-426
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• 2019

주거지 내 위치하거나 매우 인접한 곳에 무분별하게 난립된 개별입지 공장들은 궁극적으로는 준 산업단지 또는 새로운 계획입지로의 조정이 필요하다. 본 연구에서는 김포시 환경을 예로 김포시 전역에 난립된 개별입지 공장들을 새로운 지역으로 군집시킴에 따른 대기 $SO_2$ 오염도의 변화를 AERMOD 모형을 이용하여 평가하였다. 평가결과 개별입지 공장들의 공간 재배치를 통해 김포시 자체 배출원에 의한 오염도를 개선할 수 있는 가능성을 확인하였다. 재배치와 더불어 배출 굴뚝의 높이 조정과 같은 배출규제가 병행되는 경우 김포시 자체 배출원에 의한 오염도를 김포시 전체적으로 볼 때 약 70% 감소 가능하며 행정 구역별로는 최대 약 87% 감소 가능함을 정량적으로 확인하였다. 단, 군집지역으로 선정된 해당 행정구역은 김포시 전체 오염도의 변화 폭과 비교했을 때 상대적으로 큰 오염도 증가가 나타날 수 있다.

• 천문학회지
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• 제54권5호
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• pp.139-155
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• 2021

We present an updated version of the multilayer spectral inversion (MLSI) recently proposed as a technique to infer the physical parameters of plasmas in the solar chromosphere from a strong absorption line. In the original MLSI, the absorption profile was constant over each layer of the chromosphere, whereas the source function was allowed to vary with optical depth. In our updated MLSI, the absorption profile is allowed to vary with optical depth in each layer and kept continuous at the interface of two adjacent layers. We also propose a new set of physical requirements for the parameters useful in the constrained model fitting. We apply this updated MLSI to two sets of Hα and Ca II line spectral data taken by the Fast Imaging Solar Spectrograph (FISS) from a quiet region and an active region, respectively. We find that the new version of the MLSI satisfactorily fits most of the observed line profiles of various features, including a network feature, an internetwork feature, a mottle feature in a quiet region, and a plage feature, a superpenumbral fibril, an umbral feature, and a fast downflow feature in an active region. The MLSI can also yield physically reasonable estimates of hydrogen temperature and nonthermal speed as well as Doppler velocities at different atmospheric levels. We conclude that the MLSI is a very useful tool to analyze the Hα line and the Ca II 8542 line spectral daya, and will promote the investigation of physical processes occurring in the solar photosphere and chromosphere.

• 대기
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• 제32권4호
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• pp.323-340
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• 2022

We analyzed the high-resolution wind data of Aircraft-Based Observation from the Mode-Selective Enhanced Surveillance (Mode-S EHS) data in Korea. For assessment of its quality, the Mode-S wind data was compared with the ECMWF ReAnalysis 5 (ERA5) reanalysis and Aircraft Meteorological Data Relay (AMDAR) data for more than 3-months from 7 May 2021 to 24 August 2021 near Incheon International Airport, Korea. Considering that the AMDAR reports are not provided by all commercial aircraft, total number of the Mode-S derived wind data with a second sampling rate was about twice larger than that of available AMDAR wind data. After the quality control procedures by removing erroneous samples, it was found that the root mean square errors (RMSEs) of the Mode-S retrieved winds are similar to that from the AMDAR winds. In particular, between 550 and 650 hPa levels, RMSE of the Mode-S (AMDAR) zonal wind against ERA5 data was about 2.3 m s^-1 (1.9 m s^-1), and those increased to 3.3 m s^-1 (2.4 m s^-1) in 200~500 hPa levels. A similar trend was found in the meridional wind, but a distinct positive mean bias of 2.16 m s^-1 was observed between 875 and 1,000 hPa levels. Winds retrieved from the Mode-S also showed a good agreement directly with AMDAR data. As the Mode-S provides a large amount of data with a reliable quality, it can be useful for both data assimilation in the numerical weather prediction model and situational awareness of wind and turbulence for aviation safety in Korea.

• 한국산학기술학회논문지
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• 제22권6호
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• pp.492-498
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• 2021

본 연구는 수송부문에서 오염물질 배출 비중이 큰 화물차의 통행량에 영향을 미치는 요인을 분석하기 위하여 다중회귀모형을 추정하였으며, 모형 추정 결과 지역별 인구수, 도시지역 면적, GDP, 업종별(농업, 임업 및 어업, 광업, 제조업, 도매 및 소매업) 사업체수 등이 주요 변수로 검토되었다. 이러한 변수는 화물차 특성(업종, 톤급)에 따라 상이하게 나타나므로 차량 운행제한 등 관련 정책 추진 시에는 지역별 화물차 특성에 따른 통행량을 충분히 고려해야 할 필요가 있다. 특히 물류터미널 등 화물차 통행량이 많은 물류거점이 위치하지 않은 지역에 대해서는 화물차 통행에 영향을 미치는 지역별 요인을 고려하여 차량 운행제한 대상 지역을 검토해야 할 필요가 있다. 특히 본 연구의 결과에서 제시된 바와 같이 화물차 통행량과 지역 내 인구수는 양의 상관관계를 가지기 때문에 인구밀집지역에서는 화물차를 포함한 차량운행제한 검토가 필요하다. 본 연구 결과의 신뢰도를 높이기 위해서는 실제 통행량 자료를 기반으로 다중회귀모형 외 다양한 모형 추정을 통하여 추정 결과에 대한 오차를 줄여야 할 필요가 있다.

• 대기
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• 제31권2호
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• pp.185-198
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• 2021

In this study, we examined a spatial downscaling method based on Gradient and Inverse Distance Squared (GIDS) weighting to produce high-resolution grid data from a numerical weather prediction model over Korean Peninsula with complex terrain. The GIDS is a simple and effective geostatistical downscaling method using horizontal distance gradients and an elevation. The predicted meteorological variables (e.g., temperature and 3-hr accumulated rainfall amount) from the Limited-area ENsemble prediction System (LENS; horizontal grid spacing of 3 km) are used for the GIDS to produce a higher horizontal resolution (1.5 km) data set. The obtained results were compared to those from the bilinear interpolation. The GIDS effectively produced high-resolution gridded data for temperature with the continuous spatial distribution and high dependence on topography. The results showed a better agreement with the observation by increasing a searching radius from 10 to 30 km. However, the GIDS showed relatively lower performance for the precipitation variable. Although the GIDS has a significant efficiency in producing a higher resolution gridded temperature data, it requires further study to be applied for rainfall events.

• Advances in environmental research
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• 제10권1호
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• pp.17-41
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• 2021

Kazakhstan's cities experience high concentrations levels of atmospheric particulate matter (PM), which is well-known for its highly detrimental effect on the human health. A further increase in PM concentrations in the future could lead to a higher air pollution-caused morbidity and mortality, causing an increase in healthcare expenditures by the government. However, to prevent elevated PM concentrations in the future, more stringent standards could be implemented by lowering current maximum allowable PM concentration limit to Organization for Economic Co-operation and Development (OECD)'s limits. Therefore, this study aims to find out what impact this change in environmental policy towards PM has on state economy in the long run. Future PM10 and PM2.5 concentrations were estimated using multiple linear regression based on gross regional product (GRP) and population growth parameters. Dose-response model was based on World Health Organization's approach for the identification of mortality, morbidity and healthcare costs due to air pollution. Analysis of concentrations revealed that only 6 out of 21 cities of Kazakhstan did not exceed the EU limit on PM10 concentration. Changing environmental standards resulted in the 71.7% decrease in mortality and 77% decrease in morbidity cases in all cities compared to the case without changes in environmental policy. Moreover, the cost of morbidity and mortality associated with air pollution decreased by $669 million in 2030 and $2183 million in 2050 in case of implementation of OECD standards. Thus, changing environmental regulations will be beneficial in terms of both of mortality reduction and state budget saving.

• 대기
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• 제31권5호
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• pp.489-510
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• 2021

In this paper, we propose an algorithm for detecting convective initiation (CI) using GEO-KOMPSAT-2A/advanced meteorological imager data. The algorithm identifies clouds that are likely to grow into convective clouds with radar reflectivity greater than 35 dBZ within the next two hours. This algorithm is developed using statistical and qualitative analysis of cloud characteristics, such as atmospheric instability, cloud top height, and phase, for convective clouds that occurred on the Korean Peninsula from June to September 2019. The CI algorithm consists of four steps: 1) convective cloud mask, 2) cloud object clustering and tracking, 3) interest field tests, and 4) post-processing tests to remove non-convective objects. Validation, performed using 14 CI events that occurred in the summer of 2020 in Korean Peninsula, shows a total probability of detection of 0.89, false-alarm ratio of 0.46, and mean lead-time of 39 minutes. This algorithm can be useful warnings of rapidly developing convective clouds in future by providing information about CI that is otherwise difficult to predict from radar or a numerical prediction model. This CI information will be provided in short-term forecasts to help predict severe weather events such as localized torrential rainfall and hail.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.81-85
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• 2022

Mist-CVD is known to have advantages of low cost and high productivity method since the precursor solution is misting with an ultrasonic generator and reacted on the substrate under vacuum-free conditions of atmospheric pressure. However, since the deposition distribution is not uniform, various efforts have been made to derive optimal conditions by changing the angle of the substrate and the position of the outlet to improve the result of the preceding study. Therefore, in this study, a deposition distribution uniformity model was derived through the shape and position of the substrate support and the conditions of inlet flow rate using the particle tracking method of computational fluid dynamics (CFD). The results of analysis were compared with the previous studies through experiment. It was confirmed that the rate of deposition area was improved from 38.7% to 100%, and the rate of deposition uniformity was 79.07% which was higher than the predicted result of simulation. Particle tracking method can reduce trial and error in experiments and can be considered as a reliable prediction method.

• 환경영향평가
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• 제31권5호
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• pp.271-285
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• 2022

본 연구에서는 AERMOD 기상 전처리 프로그램인 AERMET에 대표적 지표기상 형식인 CD-144와 ISHD를 적용하여 처리 결과를 비교하고, 환경부 토지피복도를 고려하여 대기확산 정도를 분석하였다. 연구결과, knot 단위를 사용하는 CD-144 형식의 경우 단위 변환 오차로 인해 실제 풍속을 고려하지 못하였으나 ISHD 형식은 그대로 반영하는 것으로 나타났다. 점오염원 1시간 최대 농도값은 ISHD가 CD-144에 비해 높았으며, 그 외에는 동일하거나 낮아지는 것으로 나타났다. 환경부 토지피복도를 반영한 농도값은 토지피복도를 고려하지 않은 경우보다 최대 387% 증가하였으며, 등농도곡선 형태(곡선의 방향 및 길이)에도 차이가 있는 것으로 나타났다. 환경영향평가 및 통합환경허가에서의 모델 사용은 동일한 조건에서의 통일된 판단을 요구하므로 AERMET 사용시 ISHD 형식의 사용과 함께 모델링 지역의 토지피복을 고려할 필요가 있다.