• 대기
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• 제29권1호
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• pp.61-74
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• 2019

To investigate the observational environment, sky line and skyview factor (SVF) are calculated using a digital elevation model (DEM; 10 m spatial resolution) and 3 dimensional (3D) sky image at radiation site, Gangneung-Wonju National University (GWNU). Solar radiation is calculated using GWNU solar radiation model with and without the sky line and the SVF retrieved from the 3D sky image and DEM. When compared with the maximum sky line elevation from Skyview, the result from 3D camera is higher by $3^{\circ}$ and that from DEM is lower by $7^{\circ}$. The SVF calculated from 3D camera, DEM and Skyview is 0.991, 0.998, and 0.993, respectively. When the solar path is analyzed using astronomical solar map with time, the sky line by 3D camera shield the direct solar radiation up to $14^{\circ}$ with solar altitude at winter solstice. The solar radiation is calculated with minutely, and monthly and annual accumulated using the GWNU model. During the summer and winter solstice, the GWNU radiation site is shielded from direct solar radiation by the west mountain 40 and 60 minutes before sunset, respectively. The monthly difference between plane and real surface is up to $29.18M\;m^{-2}$ with 3D camera in November, while that with DEM is $4.87M\;m^{-2}$ in January. The difference in the annual accumulated solar radiation is $208.50M\;m^{-2}$ (2.65%) and $47.96M\;m^{-2}$ (0.63%) with direct solar radiation and $30.93M\;m^{-2}$ (0.58%) and $3.84M\;m^{-2}$ (0.07%) with global solar radiation, respectively.

• 한국물환경학회지
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• 제34권6호
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• pp.632-641
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• 2018

Algal dynamics is controlled by multiple environmental factors such as flow dynamics, water temperature, trophic level, and irradiance. Underwater irradiance penetrating from the atmosphere is exponentially decreased in water column due to absorption and scattering by water molecule and suspended particles including phytoplankton. As the exponential decrease in underwater irradiance affects algal photosynthesis, regulating their spatial distribution, it is critical to understand the light extinction characteristics to find out the mechanisms of algal dynamics more systematically. Despite the significance, the recent data have been rarely reported in the main stream areas of large rivers, Korea. In this study, the euphotic depths and light extinction coefficients were determined by monitoring the vertical variation of underwater irradiance and water quality in the main channel of Nakdong River near Dodong Seowon once a week during summer of 2016. The average values of euphotic depth and light extinction coefficient were 4.0 m and $1.3m^{-1}$, respectively. The degree of light extinction increased in turbid water due to flooding, causing an approximate 50 % decrease in euphotic depth. Also, the impact was greater than the self-shading effect during the periods of cyanobacterial bloom. The individual light extinction coefficients for background, total suspended solid and algal levels, frequently used in surface water quality modeling, were determined as $0.305m^{-1}$, $0.090m^{-1}/mg{\cdot}L^{-1}$, $0.013m^{-1}/{\mu}g{\cdot}L^{-1}$, respectively. The values estimated in this study were within or close to the ranges reported in literatures.

• 한국지반환경공학회 논문집
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• 제22권2호
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• pp.15-23
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• 2021

오염총량 개념을 반영한 매립장 사후관리종료제도 개선방안을 수도권매립지 제1매립장을 대상으로 적용하여 분석하였다. 매립가스 모델을 통해 분석한 메탄 잔여비율은 총 발생 가능량인 2,521×106 Nm3에 대하여 2020년 8.8%, 2030년 7.0%, 2040년 6.5%이었다. 2020년 이후의 표면발산 메탄량에 2005~2019년의 평균 산화율 89.1%를 적용할 경우, 실제 배출기준 메탄 잔여율은 2020년 1.01%, 2030년 0.76%, 2040년 0.70%로서 2025년 이후 메탄이 전량 표면 발산되어도 2019년 기준 표면 발산량보다 적어 사후관리 종료가 가능하였다. 침출수 수질에 대한 추이분석 결과, BOD는 2024년, COD 2047년, T-N은 2117년경에 배출허용기준을 만족할 수 있을 것으로 추정되었다. 사후관리종료를 배출부하량을 기준으로 변경할 경우 BOD는 현 시점에서 그리고 COD도 수년 내 사후관리종료가 가능하나, T-N의 경우 2041년 이후에나 가능하여 근본적인 관리방식의 전환이 필요한 것으로 분석되었다.

• 대기
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• 제31권1호
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• pp.113-141
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• 2021

The impacts of ice clouds on the energy budget of the Earth and their representation in climate models have been identified as important and unsolved problems. Ice clouds consist almost exclusively of non-spherical ice crystals with various shapes and sizes. To determine the influences of ice clouds on solar and infrared radiation as required for remote sensing retrievals and numerical models, knowledge of scattering and microphysical properties of ice crystals is required. A conventional method for representing the radiative properties of ice clouds in satellite retrieval algorithms and numerical models is to combine measured microphysical properties of ice crystals from field campaigns and pre-calculated single-scattering libraries of different shapes and sizes of ice crystals, which depend heavily on microphysical and scattering properties of ice crystals. However, large discrepancies between theoretical calculations and observations of the radiative properties of ice clouds have been reported. Electron microscopy images of ice crystals grown in laboratories and captured by balloons show varying degrees of complex morphologies in sub-micron (e.g., surface roughness) and super-micron (e.g., inhomogeneous internal and external structures) scales that may cause these discrepancies. In this study, the current idealized models representing morphologies of ice crystals and the corresponding numerical methods (e.g., geometric optics, discrete dipole approximation, T-matrix, etc.) to calculate the single-scattering properties of ice crystals are reviewed. Current problems and difficulties in the calculations of the single-scattering properties of atmospheric ice crystals are addressed in terms of cloud microphysics. Future directions to develop physically consistent ice-crystal models are also discussed.

• 대기
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• 제30권4호
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• pp.377-390
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• 2020

Not only emissions, but also atmospheric circulation is a key factor that affects local particulate matters (PM) concentrations in Korea through ventilation effects and transboundary transports. As part of the atmospheric circulation, air stagnation especially adversely affects local air quality due to weak ventilation. This study investigates the large-scale circulation related to air stagnation over Korea during winter and projects the climate change impacts on atmospheric patterns, using observed PM data, reanalysis and regional climate projections from HadGEM3-RA with Modified Korea Particulate matter Index. Results show that the stagnation affects the PM concentration, accompanied by pressure ridge at upper troposphere and weaken zonal pressure gradient at lower troposphere. Downscaling using HadGEM3-RA is found to yield Added-Value in the simulated low tropospheric winds. For projection of future stagnation, SSP5-8.5 and SSP1-2.6 (high and low emission) scenarios are used here. It has been found that the stagnation condition occurs more frequently by 11% under SSP5-8.5 and by 5% under SSP1-2.6 than in present-day climate and is most affected by changes in surface wind speed. The increase in the stagnation conditions is related to anticyclonic circulation anomaly at upper troposphere and weaken meridional pressure gradient at lower troposphere. Considering that the present East Asian winter monsoon is mainly affected by change in zonal pressure gradient, it is worth paying attention to this change in the meridional gradient. Our results suggest that future warming condition increase the frequency of air stagnation over Korea during winter with response of atmospheric circulation and its nonlinearity.

• 한국해안·해양공학회논문집
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• 제32권6호
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• pp.373-383
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• 2020

본 연구에서는 한반도 중심 해역을 포함하는 북서태평양 영역에서의 폭풍해일 예측을 위해 NEMO(Nucleus for European Modelling of the Ocean) 모형을 이용하여 지역규모의 폭풍해일 예측시스템을 구축하였다. 이 시스템은 조석과 해일 예측으로 구성되어 있으며보다 정확한 폭풍해일을 예측하기 위해 수심자료와 대기-해양 경계에서의 모수화(parameterization) 최적화 과정을 수행하였다. 이를 통해 2018년 8~10월과 태풍 솔릭 사례에 대하여 국립해양조사원 조위 관측자료를 이용한 통계 방법을 적용하여 검증을 수행하고, 이를 POM(Princeton Ocean Model) 기반의 예측모델 결과와 비교하였다. 수행결과 NEMO 기반의 폭풍해일 예측시스템이 POM 기반의 예측결과에 비해 평균오차와 RMSE가 각각 약 29%와 약 20% 감소한 것으로 나타났으며, 태풍 시기에도 NEMO 기반 예측결과에서 전반적으로 오차가 낮게 나타났다.

• 대기
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• 제30권4호
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• pp.439-454
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• 2020

This study investigates the change in the fine particulate matter (PM2.5) concentration and World Health Organization (WHO) air quality index (AQI) in East Asia (EA) under Shared Socioeconomic Pathways (SSPs). AQI is an indicator of increasing levels about health concern, divided into six categories based on PM2.5 annual concentrations. Here, we utilized the ensemble results of UKESM1, the climate model operated in Met Office, UK, for the analysis of long-term variation during the historical (1950~2014) and future (2015~2100) period. The results show that the spatial distributions of simulated PM2.5 concentrations in present-day (1995~2014) are comparable to observations. It is found that most regions in EA exceeded the WHO air quality guideline except for Japan, Mongolia regions, and the far seas during the historical period. In future scenarios containing strong air quality (SSP1-2.6, SSP5-8.5) and medium air quality (SSP2-4.5) controls, PM2.5 concentrations are substantially reduced, resulting in significant improvement in AQI until the mid-21st century. On the other hand, the mild air pollution controls in SSP3-7.0 tend to lead poor AQI in China and Korea. This study also examines impact of increased in PM2.5 concentrations on downward shortwave energy at the surface. As a result, strong air pollution controls can improve air quality through reduced PM2.5 concentrations, but lead to an additional warming in both the near and mid-term future climate over EA.

• 한국농림기상학회지
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• 제24권3호
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• pp.179-189
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• 2022

우박은 강한 상승 기류에 의하여 빙결 고도 이상에서 수적이 상승과 하강을 반복함에 따라 얼음덩어리로 성장 후 지상으로 낙하하는 현상을 의미한다. 이러한 우박은 단기간 내 국지적인 영역에서 발생하여 농림업 분야에 큰 피해를 미치지만 우박에 대한 예측을 수행하는 국내 연구는 부족한 실정이다. 이에 본 연구에서는 국가농림기상센터 LAMP를 이용한 우박 예측을 소개하고, 2020년 1월부터 2021년 7월까지 발생한 50개의 우박 사례에 대하여 LAMP 우박 예측 성능을 측정하였다. 본 연구에서 조사된 우박 사례의 경우 봄철에 주로 오후 시간대에 발생 빈도가 높았고, 우박의 지속 시간은 평균 15분이었으며, 우박의 직경은 1 cm로 나타났다. LAMP의 우박 예측 성능을 정성적으로 평가한 결과 50개의 사례 가운데 35개 사례에 대하여 우박 예측에 성공하여 탐지율은 70%로 나타났다. LAMP의 우박 예측 성능은 우박을 예측하는 시간이 길어짐에 따라 저하된 것으로 사료된다. 실제 우박 사례에 대한 레이더 반사도를 조사한 결과, 고도에 무관하게 최대 반사도가 40 dBZ 이상이었고, 우박 사례의 약 50%가 30~50 dBZ 사이로 나타났는데, 이러한 결과는 현재 LAMP의 우박 예측 성능을 향후 보완하기 위한 자료로 활용될 것이다. LAMP를 활용한 우박 예측 성능이 향상됨으로써 농림업 분야에서 망 피복 등의 선제적 조치를 통해 우박에 의한 경제적 손실이 줄어들 것으로 기대된다.

• Composites Research
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• 제36권1호
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• pp.37-41
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• 2023

선박의 평형수처리장치 전해조 내부 용액은 해수를 전기분해 시 DSA(Dimension Stable Anode) 전극에서 생성되는 수산화물로 인하여 높은 알칼리성 분위기를 생성한다. 본 연구에서는 기존 평형수처리장치 배관에 사용되어지는 PE 코팅 강관 배관의 취약성을 대체 가능한 복합재료로써 4가지 소재를 선정하였으며, 이들 BRE(Basalt fiber reinforced epoxy), BRP(Basalt fiber reinforced unsaturated polyester), GRE(Glass fiber reinforced epoxy), GRP(Glass fiber reinforced unsaturated polyester)를 강 알칼리성 NaOH 용액에 720시간 침지 후 마찰 및 마모 시험을 통하여 재료 마찰 깊이에 따른 마찰계수와 섬유와 수지 간 계면 결합 거동을 분석하였다. 그 결과, 수지와 섬유 간의 게면 분리 현상에 대한 메커니즘을 도출하였다. 또한, 불포화폴리에스테르와 같이 상대적으로 낮은 계면 결합력의 갖는 소재의 경우, 알칼리성 용액에 침지 시간이 길어질수록 표면에서부터 시작된 열화가 내부로 급격하게 확산되어 마찰 계수의 감소로 이어지는 경향을 나타냈다.

• 대순사상논총
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• 제24_2집
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• pp.117-164
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• 2015

Religion is not fixed and permanent and is constantly transforming and changing phenomenon. But in some religions, religious culture happens that emphasize the original and authentic teaching of the founder and removes the other accumulations among the accumulated religious tradition. So some religious communities advocate the original teaching of the founder and insist that they are the orthodox and the others are heresy and make the theory of true transmission etc. Jongtonglon(宗統論) of Daesoonjinrihoe(大巡眞理會) looks similar to the theory of true transmission on the surface. The aim of this paper is the contribution to the understanding of Daesoon thought and the religious culture of Daesoonjinrihoe by studying the characteristics of Jongtonglon. I want to highlight on the characteristics of Jongtonglon by comparing it to Bubmaeklon(法脈論) of Korean Buddhism. Bubmaek(法脈) of Korean Buddhism is well showed in the constitution of Jogaejong(曺溪宗) that represents Korean Buddhism. The constitution says that Jogaejong considers SakyaMuni the main Buddha and Doyi (道義) the founder of Jogaejong and BojoJinul(普照知訥)·TaegoBou (太古普愚) the restorer of tradition and also says that Jogaejong succeedes Cheongheo(淸虛) and Buhyu(浮休). Between SakyaMuni and Doyi, there are several monks of Seocheon(西天)-28Choseol (祖說) and China-6Choseol(祖說). Jinul is highly praised for enhancing the atmosphere of performance of Jogaejong and Bou was regarded as the founder of Jogaejong since late Joseon dynasty. In modern times there were conflicts between Bojojongjoseol(普照宗祖說) and Taegojongjoseol(太古宗祖說), but today's Bubmaek(法脈) of Korean Buddhism was erected after the conflicts was controled. Jongtong of Daesoonjinrihoe was erected by Jo Jengsan(趙鼎山) Doju(道主) who was received Heaven's will through divine revelation. Dojeon(都典) succeeded Jongtong by Doju's will and he didn't say a word when he went to Heaven. So the succession of Jongtong is ended. The first characteristic of Jongtonglon of Daesoonjinrihoe is that the succession of Jongtong was decided by Heaven and has been expected from long ago. The second, Jongtonglon has the sacred characteristic which is not shown in Bubmaeklon. The third, the distinction between Yeonwun(淵源) and Yeonun(緣運) is not appeared in Bubmaeklon. The fourth, Jongtonglon has more anti-syncretic feature than Bubmaeklon. The fifth, Yeonun(緣運) and Bubmaeklon are different in that feature. As Jongtonglon occupies a prominent place in Daesoonjinrihoe, the understanding of it can contribute to grasp the doctrine and culture of Daesoonjinrihoe.