• Journal of Radiation Protection and Research
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• 제28권4호
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• pp.311-319
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• 2003

본 연구는 격자형 가우시안 플룸모형을 Matlab언어를 이용하여 구축한 후, 영광원자력시설의 부지에서 시행된 추적자 확산실험자료를 이용하여 예측력을 평가하였다. 풍하방향으로는 20km까지 10m간격으로 격자를 구분하였으며, 풍하방향에 수직인 지표방향은 방출점을 중심으로 상하 5km를 각각 10m 간격으로 구분하여 $1,990{\times}1,000{\times}1$의 격자망으로 구성하였다. 실험당시의 대기안정도는 P-G방법에 의해 B등급으로 나타났으며 이를 이용하여 각 격자의 농도예측을 수행하였다. 반경 3km의 A-line의 경우가 반경 8km근방의 B-line에 비해 격자형 가우시안 모형의 예측력이 뛰어난 것으로 나타났으며, 방출점에서 거리가 멀어질수록 P-G방법에 의한 확산폭의 산정은 모형의 예측력을 떨어뜨리는 것으로 나타났다. 모형의 예측력을 향상시키기 위하여 P-G 방법에 의한 확산폭인 sigma y 및 sigma z를 선형계획법을 이용하여 수정하였다. 수정된 확산인자를 적용한 결과 3km와 8km 모두 모형의 예측력이 향상됨을 확인할 수 있었다. 향후 추적자 확산실험 데이터의 축적을 통해 기상조건에 따른 확산인자에 대한 경험식을 개발한다면 격자형 가우시안 모델이 원자력시설에서의 대기질 환경영향평가에 유용하게 쓰일 수 있을 것으로 기대된다.

• 한국환경과학회지
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• 제12권3호
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• pp.265-274
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• 2003

The Pasquill-Gifford stability category is a very important scheme of the Gaussian type dispersion model defined the complex turbulence state of the atmosphere by A grade(very unstable) to F grade(very stable). But there has been made a point out that this stability category might decrease the predictability of the model because it was each covers a broad range of stability conditions, and that they were very site specific. The APSM (Air Pollution Simulation Model) was composed of the turbulent parameters, i.e. friction velocity(${\mu}$$\_$*/), convective velocity scale($\omega$$\_$*/) and Monin-Obukhov length scale(Ｌ) for the purpose of the performance increasing on the case of the unstable atmospheric conditions. And the PDF (Probability Density Function)model was used to express the vertical dispersion characteristics and the profile method was used to calculate the turbulent characteristics. And the performance assessment was validated between APSM and EPA regulatory models(TEM, ISCST), tracer experiment results. There were very good performance results simulated by APSM than that of TEM, ISCST in the short distance (<1415 m) from the source, but increase the simulation error(%) to stand off the source in others. And there were differences in comparison with the lateral dispersion coefficient($\sigma$$\_$y/) which was represent the horizontal dispersion characteristics of a air pollutant in the atmosphere. So the different calculation method of $\sigma$$\_$y/ which was extrapolated from a different tracer experiment data might decrease the simulation performance capability. In conclusion, the air pollution simulation model showed a good capability of predict the air pollution which was composed of the turbulent parameters compared with the results of TEM and ISCST for the unstable atmospheric conditions.

• 환경영향평가
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• 제10권2호
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• pp.123-133
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• 2001

Gaussian dispersion model is the most widely used tool for the ground level air pollution simulation. Though in spite of the convenience there are important problems on the Pasquill- Gifford' stability classification scheme which was used to define the turbulent state of the atmosphere or to describe the dispersion capabilities of the atmosphere which was each covers a broad range of stability conditions, and that they were very site specific, and the vertical dispersion calculation formula on the case of the unstable atmospheric condition. This paper was carried out to revise the Gaussian dispension model for the purposed of increase the modeling performance and propose the revised model, which was composed of the turbulent characteristics in the unstable atmospheric conditions. The proposed models in this study were composed of the profile method, Monin-Obukhove length, the probability density function model and the lateral dispersion function which was composed of the turbulent parameters, $u_*$(friction velocity), $w_*$(convective velocity scale), $T_L$(lagrangian time scale) for the model specific. There were very good performance results compare with the tracer experiment result on the case of the short distance (<1415m) from the source, but increase the simulation error(%) to stand off the source in the all models. In conclusion, the revised Gaussian dispersion model using the turbulent characteristics may be a good contribution for the development of the air pollution simulation model.