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문정혁,강영봉,박규은 濟州大學校 師範大學 科學敎育硏究所 1994 科學敎育 Vol.11 No.1
The difficulties involved in teaching the concept of entropy in the form of Clausius, which is the common practice in physics education today, are dicussed and, as an alternative to this, the concept of entropy in the form of Boltzamnn, which is using the number of quantum state, is suggested. This form of entropy is shown to be not only nearer to the core of the concept, but also much easier to grasp and more apt to stimulate the student's interest. A few examples, ie, the laws of Thermodynamics, and equation of state of an ideal gas, are included in order to show the fruitfulness and very gen-eral application of this relation.
KORUS-AQ 기간 동안 초기 입력 자료에 따른 WRF 기상장 모의 결과 비교
문정혁,전원배,이화운,Mun, Jeonghyeok,Jeon, Wonbae,Lee, Hwa Woon 한국환경과학회 2020 한국환경과학회지 Vol.29 No.1
Recently, a variety of modeling studies have been conducted to examine the air quality over South Korea during the Korea - United States Air Quality (KORUS-AQ) campaign period (May 1 to June 10, 2016). This study investigates the impact of different meteorological initializations on atmospheric modeling results. We conduct several simulations during the KORUS-AQ period using the Weather Research and Forecasting (WRF) model with two different initial datasets, which is FNL of NCEP and ERA5 of ECMWF. Comparing the raw initial data, ERA5 showed better accuracy in the temperature, wind speed, and mixing ratio fields than those of NCEP-FNL. On the other hand, the results of WRF simulations with ERA5 showed better accuracy in the simulated temperature and mixing ratio than those with FNL, except for wind speed. Comparing the nudging efficiency of temperature and wind speed fields, the grid nudging effect on the FNL simulation was larger than that on the ERA5 simulation, but the results of mixing ratio field was the opposite. Overall, WRF simulation with ERA5 data showed a better performance for temperature and mixing ratio simulations than that with FNL data. For wind speed simulation, however, WRF simulation with FNL data indicated more accurate results compared to that with ERA5 data.
초기 입력 자료에 따른 WRF 기상장 모의 결과 차이 - ERA-Interim과 FNL자료의 비교
문정혁 ( Jeonghyeok Mun ),이화운 ( Hwa Woon Lee ),전원배 ( Wonbae Jeon ),이순환 ( Soon-hwan Lee ) 한국환경과학회 2017 한국환경과학회지 Vol.26 No.12
In this study, we investigated the impact of different initial data on atmospheric modeling results using the Weather Research and Forecast (WRF) model. Four WRF simulations were conducted with different initialization in March 2015, which showed the highest monthly mean PM10 concentration in the recent ten years (2006-2015). The results of WRF simulations using NCEP-FNL and ERA-Interim were compared with observed surface temperature and wind speed data, and the difference of grid nudging effect on WRF simulation between the two data were also analyzed. The FNL simulation showed better accuracy in the simulated temperature and wind speed than the Interim simulation, and the difference was clear in the coastal area. The grid nudging effect on the Interim simulation was larger than that of the FNL simulation. Despite of the higher spatial resolution of ERA-Interim data compared to NCEP-FNL data, the Interim simulation showed slightly worse accuracy than those of the FNL simulation. It was due to uncertainties associated with the Sea Surface Temperature (SST) field in the ERA-Interim data. The results from the Interim simulation with different SST data showed significantly improved accuracy than the standard Interim simulation. It means that the SST field in the ERA-Interim data need to be optimized for the better WRF simulation. In conclusion, although the WRF simulation with ERA-Interim data does not show reasonable accuracy compared to those with NCEP-FNL data, it would be able to be Improved by optimizing the SST variable.
국내 오존 모의 농도에 대한 해양 배출량의 영향 정량 분석
박재형,전원배,문정혁,김동진 한국환경과학회 2021 한국환경과학회지 Vol.30 No.5
In this study, we quantitatively analyze the effect of ocean emission sources on the simulated O3 concentrations in South Korea using the community multi-scale air quality (CMAQ) model. To analyze changes in O3 concentrations by ocean emissions, two different CMAQ simulations considering ocean emissions (OE case) and without considering ocean emissions (NE case) were conducted during the Korea-United States air quality (KORUS-AQ) campaign period (May–June 2016). The changes in the simulated O3 concentrations due to the effect of ocean emissions (OE case-NE case) appeared mostly in the ocean areas (+1.201 ppbv). The effect of ocean emissions was positive during the daytime (+1.813 ppbv), but negative during the nighttime (–0.612 ppbv). Analysis using the integrated process rate (IPR) confirmed that the increase or decrease in O3 concentration by ocean emissions was mainly due to chemical processes. Further analysis using the integrated reaction rate (IRR) showed that the daytime increase in O3 concentration was mainly attributable to the increased O3 production via O + O2 + M → O3 + M reaction as photolysis of NO2 increased due to the added ocean emissions. The nighttime decrease in O3 concentration was mainly due to the increased O3 titration by NO (NO + O3 → O2 + NO2) due to the increased NO emission. These results indicate that the changes in the concentration O3 in the sea area by the effect of ocean emissions are mainly due to increased NOx emissions. However, there could be a number of uncertainties in ocean emissions data used in this study, thus continuous comparative research using the most updated data will need to be carried out in the future.