기상-대기질 모델을 활용한 2010~2014년 우리나라 PM₁₀ 변동 특성 분석: 기상 요인을 중심으로

남기표 ( Ki-pyo Nam ),이대균 ( Dae-gyun Lee ),박지훈 ( Ji-hoon Park ) 한국환경영향평가학회 2018 환경영향평가 Vol.27 No.5

The impact of meteorological condition on surface PM₁₀ concentrations in South Korea was quantitatively simulated from 2010 to 2014 using WRF (ver.3.8.1) and CMAQ (5.0.2) model. The result showed that seasonal standard deviations of PM10 induced by change of weather conditions were 4.8 μg/㎥, 1.7 μg/㎥, 1.7 μg/㎥, 4.2 μg/㎥ for spring, summer, autumn and winter compared to 2010, respectively, with the annual mean standard deviation of about 2.6 μg/㎥. The results of 18 regions in South Korea showed standard deviation of more than 1 μg/㎥ in all regions and more than 2 μg/㎥ in Seoul, Northern Gyeonggi, Southern Southern Gyeonggi, Western Gangwon and Northern Chungcheong in South Korea.

Brute-Force Method를 이용한 국내외 PM<SUB>2.5</SUB> 기여도 산정 방법에 대한 고찰

남기표(Ki-pyo Nam),이한솔(Han-sol Lee),이진주(Jin-ju Lee),박현주(Hyun-ju Park),최진영(Jin-young Choi),이대균(Dae-gyun Lee) 한국대기환경학회 2019 한국대기환경학회지 Vol.35 No.1

In this study, we analyzed the variation of PM<SUB>2.5</SUB> concentration and the range of domestic and foreign contribution according to the variation range of emission when calculating the contribution of BFM (Brute-Force Method) to the CMAQ model. As a result of modeling by reducing the domestic emissions by 20%, 40%, 60%, 80%, and 100% in high-concentration PM<SUB>2.5</SUB> cases in January 2017, the simulated PM<SUB>2.5</SUB> concentrations were decreased by 3.2 μg/m³, 6.5 μg/m³, 10.1 μg/m³, 14.1 μg/m³, 20.7 μg/m³, respectively, and these results show non-linear characteristics between emission and PM<SUB>2.5</SUB> concentration. The non-linearity between these emissions and PM<SUB>2.5</SUB> concentration also found to have an effect on the estimation results of the domestic and foreign contribution using BFM. In particular, the results of domestic and foreign contribution evaluation under the zero-out condition for the period covered by this study showed a difference of more than 6% from the contribution evaluation results calculated under the 20~80% emission variation condition. It was confirmed that the results of the contribution evaluation for PM<SUB>2.5</SUB> could be slightly different according to the emission fluctuation condition when applying BFM to the air quality model.

효율적인 대기정책 마련을 위한 대기질 모델 활용방안 고찰

남기표(Ki-Pyo Nam),이대균(Dae-Gyun Lee),이재범(Jae-Bum Lee),최기철(Ki-Cheol Choi),장임석(Lim-Seok Jang),최광호(Kwang-Ho Choi) 한국대기환경학회 2018 한국대기환경학회지 Vol.34 No.5

In order to develop effective emission abatement strategies for coal-fired power plants, we analyzed the shutdown effects of coal-fired power plants on PM<SUB>2.5</SUB> concentration in June by employing air quality model for the period from 2013 to 2016. WRF (Weather Research and Forecast) and CMAQ (Community Multiscale Air Quality) models were used to quantify the impact of emission reductions on the averaged PM<SUB>2.5</SUB> concentrations in June over Chungcheongnam-do area in Korea. The resultant shutdown effects showed that the averaged PM<SUB>2.5</SUB> concentration in June decreased by 1.2% in Chungcheongnam-do area and decreased by 2.3% in the area where the surface air pollution measuring stations were located. As a result of this study, it was confirmed that it is possible to analyze policy effects considering the change of meteorology and emission and it is possible to quantitatively estimate the influence at the maximum impact region by utilizing the air quality model. The results of this study are expected to be useful as a basic data for analyzing the effect of PM<SUB>2.5</SUB> concentration change according to future emission changes.

동아시아 지역의 계절별 기상패턴에 따른 우리나라 PM_2.5 농도 및 기여도 특성 분석: 2015년 집중측정 기간을 중심으로

남기표,이대균,장임석,Nam, Ki-Pyo,Lee, Dae-Gyun,Jang, Lim-Seok 한국환경영향평가학회 2019 환경영향평가 Vol.28 No.3

In this study, the characteristics of seasonal $PM_{2.5}$ behavior in South Korea and other Northeast Asian regions were analyzed by using the $PM_{2.5}$ ground measurement data, weather data, WRF and CMAQ models. Analysis of seasonal $PM_{2.5}$ behavior in Northeast Asia showed that $PM_{2.5}$ concentration at 6 IMS sites in South Korea was increased by long-distance transport and atmospheric congestion, or decreased by clean air inflow due to seasonal weather characteristics. As a result of analysis by applying BFM to air quality model, the contribution from foreign countries dominantly influenced the $PM_{2.5}$ concentrations of Baengnyeongdo due to the low self-emission and geographical location. In the case of urban areas with high self-emissions such as Seoul and Ulsan, the $PM_{2.5}$ contribution from overseas was relatively low compared to other regions, but the standard deviation of the season was relatively high. This study is expected to improve the understanding of the air pollutant phenomenon by analyzing the characteristics of $PM_{2.5}$ behavior in Northeast Asia according to the seasonal weather condition change. At the same time, this study can be used to establish the air quality policy in the future, knowing that the contribution of $PM_{2.5}$ concentration to the domestic and overseas can be different depending on the regional emission characteristics.

기후변화 취약성 지수 산출을 위한 한반도 관측 기후 특성 분석

남기표 ( Ki Pyo Nam ),강정언 ( Jeong Eon Kang ),김철희 ( Cheol Hee Kim ) 한국환경영향평가학회 2011 환경영향평가 Vol.20 No.6

Climate vulnerability index is usually defined as a function of the climate exposure, sensitivity, and adaptive capacity, which requires adequate selection of proxy variables of each variable. We selected and used 9 proxy variables related to climate exposure in the literature, and diagnosed the adequacy of them for application in Korean peninsula. The selected proxy variables are: four variables from temperature, three from precipitation, one from wind speed, and one from relative humidity. We collected climate data over both previous year (1981~2010) and future climate scenario (A1B scenario of IPCC SERES) for 2020, 2050, and 2100. We introduced the spatial and temporal diagnostic statistical parameters, and evaluated both spatial and time variabilities in the relative scale. Of 9 proxy variables, effective humidity indicated the most sensitive to climate change temporally with the biggest spatial variability, implying a good proxy variable in diagnostics of climate change vulnerability in Korea. The second most sensitive variable is the frequency of strong wind speed with a decreasing trend, suggesting that it should be used carefully or may not be of broad utility as a proxy variable in Korea. The A1B scenario of future climate in 2020, 2050 and 2100 matches well with the extension of linear trend of observed variables during 1981~2010, indicating that, except for strong wind speed, the selected proxy variables can be effectively used in calculating the vulnerability index for both past and future climate over Korea. Other local variabilities for the past and future climate in association with climate exposure variables are also discussed here.

WRF-CMAQ 모델링 시스템을 활용한 PM_2.5 농도변동 원인 분석: 2016년과 2017년의 가을철을 중심으로

남기표 ( Ki-pyo Nam ),임용재 ( Yong-jae Lim ),박지훈 ( Ji-hoon Park ),김덕래 ( Deok-rae Kim ),이재범 ( Jae-bum Lee ),김상민 ( Sang-min Kim ),정동희 ( Dong-hee Jung ),최기철 ( Ki-chul Choi ),박현주 ( Hyun-ju Park ),이한솔 ( Han-sol 한국환경영향평가학회 2018 환경영향평가 Vol.27 No.2

It was analyzed to identify the cause of PM_2.5 concentration changes for the fall in 2016 and 2017 in South Korea using ground measurement data such as meterological variables and PM_2.5, AOD from GOCI satellite, and WRF-CMAQ modeling system. The result of ground measurement data showed that the PM_2.5 concentrations for the fall in 2017 decreased by 12.3% (3.0 μg/㎥) compared to that of 2016. The difference of PM_2.5 concentrations between 2016 and 2017 mainly occurred for 11 Oct. - 20 Oct. (CASE1) and 15 Nov. - 19 Nov. (CASE2) when weather conditions were difficult to long-range transport from foreign regions and favored atmospheric ventilation in 2017 compared to 2016. Simulated PM_2.5 concentrations in 2017 decreased by 64.0% (23.1 μg/㎥) and 35.7% (12.2 μg/㎥) during CASE1 and CASE2, respectively. These results corresponded to the changes in observed PM_2.5 concentrations such as 53.6% for CASE1 and 47.8% for CASE2. It is implied that the changes in weather conditions affected significantly the PM_2.5 concentrations for the fall between 2016 and 2017. The contributions to decreases in PM_2.5 concentrations was assessed as 52.8% by long-range transport from foreign regions and 47.2% by atmospheric ventilation effects in domestic regions during CASE1, whereas their decreases during CASE2 were affected by 66.4% from foreign regions and 33.6% in domestic regions.

표준화 방법에 따른 기후변화 취약성 지수의 민감성 연구

남기표 ( Ki Pyo Nam ),김철희 ( Cheol Hee Kim ) 한국환경영향평가학회 2013 환경영향평가 Vol.22 No.6

IPCC showed that calculation of climate vulnerability index requires standardization process of various proxy variables for the estimation of climate exposure, sensitivity, and adaptive capacity. In this study, four different methodologies of standardization methods: Z-score, Rescaling, Ranking, and Distance to the reference country, are employed to evaluate climate vulnerability- VRI (Vulnerability-Resilience Indicator) over Korean peninsula, and the error ranges of VRI, arising from employing the different standardization are estimated. All of proxy variables are provided by CCGIS (Climate Change adaptation toolkit based on GIS) which hosts information on both past and current socio-economic data and climate and environmental IPCC SRES (A2, B1, A1B, A1T, A1FI, and A1 scenarios) climate data for the decades of 2000s, 2020s, 2050s, and 2100s. The results showed that Z-score and Rescaling methods showed statistically undistinguishable results with minor differences of spatial distribution, while Ranking and Distance to the reference country methods showed some possibility to lead the different ranking of VRI among South Korean provinces, depending on the local characteristics and reference province. The resultant VRIs calculated from different standardization methods showed Cronbach`s alpha of more than 0.84, indicating that all of different methodologies were overall consistent. Similar horizontal distributions were shown with the same trends: VRI increases as province is close to the coastal region and/or it close toward lower latitude, and decreases as it is close to urbanization area. Other characteristics of the four different standardization are discussed in this study.

The Comparison of Image Quality and Quantitative Indices by Wide Beam Reconstruction Method and Filtered Back Projection Method in Tl-201 Myocardial Perfusion SPECT

윤순상,남기표,심동오,김동석,Yoon, Soon-Sang,Nam, Ki-Pyo,Shim, Dong-Oh,Kim, Dong-Seok The Korean Society of Nuclear Medicine Technology 2010 핵의학 기술 Vol.14 No.2

Purpose: The Xpress3.$cardiac^{TM}$ which is a kind of wide beam reconstruction (WBR) method developed by UltraSPECT (Haifa, Israel) enables the acquisition of at quarter time while maintaining image quality. The purpose of this study is to investigate the usefulness of WBR method for decreasing scan times and to compare to it with filtered back projection (FBP), which is the method routinely used. Materials and Methods: Phantom and clinical studies were performed. The anthropomorphic torso phantom was made on an equality with counts from patient's body. The Tl-201 concentrations in the compartments were 74 kBq (2 ${\mu}Ci$)/cc in myocardium, 11.1 kBq (0.3 ${\mu}Ci$)/cc in soft tissue, and 2.59 kBq (0.07 ${\mu}Ci$)/cc in lung. The non-gated Tl-201 myocardial perfusion SPECT data were acquired with the phantom. The former study was scanned for 50 seconds per frame with FBP method, and the latter study was acquired for 13 seconds per frame with WBR method. Using the Xeleris ver. 2.0551, full width at half maximum (FWHM) and average image contrast were compared. In clinical studies, we analyzed the 30 patients who were examined by Tl-201 gated myocardial perfusion SPECT in department of nuclear medicine at Asan Medical Center from January to April 2010. The patients were imaged at full time (50 second per frame) with FBP algorithm and again quarter-time (13 second per frame) with the WBR algorithm. Using the 4D MSPECT (4DM), Quantitative Perfusion SPECT (QPS), and Quantitative Gated SPECT (QGS) software, the summed stress score (SSS), summed rest score (SRS), summed difference score, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were analyzed for their correlations and statistical comparison by paired t-test. Results: As a result of the phantom study, the WBR method improved FWHM more than about 30% compared with FBP method (WBR data 5.47 mm, FBP data 7.07 mm). And the WBR method's average image contrast was also higher than FBP method's. However, in result of quantitative indices, SSS, SDS, SRS, EDV, ESV, EF, there were statistically significant differences from WBR and FBP(p<0.01). In the correlation of SSS, SDS, SRS, there were significant differences for WBR and FBP (0.18, 0.34, 0.08). But EDV, ESV, EF showed good correlation with WBR and FBP (0.88, 0.89, 0.71). Conclusion: From phantom study results, we confirmed that the WBR method reduces an acquisition time while improving an image quality compared with FBP method. However, we should consider significant differences in quantitative indices. And it needs to take an evaluation test to apply clinical study to find a cause of differences out between phantom and clinical results.

PET/CT검사에서 CT의 확대 유효시야 적용이 표준화섭취계수에 미치는 영향

박순기,남기표,김경식,신상기,Park, Soon-Ki,Nam, Ki-Pyo,Kim, Kyeong-Sik,Shin, Sang-Ki 대한핵의학기술학회 2009 핵의학 기술 Vol.13 No.1

Purpose: The purpose of this study was to evaluate the effect of extended CT field of view (FOV) on PET/CT of Standardized uptake value (SUV) when imaging extends beyond the CT FOV. Materials and Methods: CT images were reconstructed at different FOV sizes (500 and 700 mm). Two sets of CT images were reconstructed from the CT projection data by using two FOV sizes. Twenty patients were used in this study. PET images were reconstructed using attenuation maps with 500 mm CT FOV and 700 mm extended CT FOV images. Region of interests (ROIs) drawn on the PET images. In addition, twenty patients' PET images reconstructed by 500 mm CT FOV and 700 mm extended CT FOV were compared with $SUV_{max}$. Results: When using attenuation maps with 700 mm extended CT FOV, the $SUV_{max}$ analysis of liver (p=0.000), lung (p=0.007), mediastinum (p=0.001) were statistically significant. Conclusions: 700 mm extended CT FOV helps to recover the true activity distribution in the PET emission data. In addition, 700 mm extended CT FOV has affected SUV measurement of liver, lung, mediastinum.

심근관류 SPECT에서 움직임 보정 방법들의 비교

박장원,남기표,이동훈,김성환,Park, Jang-Won,Nam, Ki-Pyo,Lee, Hoon-Dong,Kim, Sung-Hwan 대한핵의학기술학회 2014 핵의학 기술 Vol.18 No.2

Purpose Patient motion during myocardial perfusion SPECT can produce images that show visual artifacts and perfusion defects. This artifacts and defects remain a significant source of unsatisfactory myocardial perfusion SPECT. Motion correction has been developed as a way to correct and detect the patient motion for reducing artifacts and defects, and each motion correction uses different algorithm. We corrected simulated motion patterns with several motion correction methods and compared those images. Materials and Methods Phantom study was performed. The anthropomorphic torso phantom was made with equal counts from patient's body and simulated defect was added in myocardium phantom for to observe the change in defect. Vertical motion was intentionally generated by moving phantom downward in a returning pattern and in a non-returning pattern throughout the acquisition. In addition, Lateral motion was generated by moving phantom upward in a returning pattern and in a non-returning pattern. The simulated motion patterns were detected and corrected similarly to no-motion pattern image and QPS score, after Motion Detection and Correction Method (MDC), stasis, Hopkins method were applied. Results In phantom study, Changes of perfusion defect were shown in the anterior wall by the simulated phantom motions, and inferior wall's defect was found in some situations. The changes derived from motion were corrected by motion correction methods, but Hopkins and Stasis method showed visual artifact, and this visual artifact did not affect to perfusion score. Conclusion It was confirmed that motion correction method is possible to reduce the motion artifact and artifactual perfusion defect, through the apply on the phantom tests. Motion Detection and Correction Method (MDC) performed better than other method with polar map image and perfusion score result.