Center for Atmospheric and Environmental Modeling

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Center for Atmospheric and Environmental Modeling

Guro gu, South Korea

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Park S.-U.,Center for Atmospheric and Environmental Modeling | Park M.-S.,Engine World
Atmospheric Environment | Year: 2014

Aerosol size distributions of observed mass concentrations at the Naiman site in Inner Mongolia that is one of the major Asian dust source regions have been examined for the period from April 2010 to July 2012. The total number of 262 sampled data using the 10-stage quartz crystal microbalance (QCM) cascade impactor is obtained by presetting the frequency changes of 40Hz during April 2010, 60Hz for the period of 28 April-16 September 2010 and 70Hz from 1 November 2010-29 July 2012. The total mass concentrations (PM10) measured by the QCM cascade impactor are modified to have the same sampling time of 60min with the help of the 1-h averaged PM10 concentration measured by the beta gauge at the same site. These modified QCM data are classified into the local dust emission case of 196 and the dust advection case of 66. The local dust emission case is defined when the calculated dust flux with the two-level (3m and 15m high) measured PM10 concentrations by the beta-gauge is upward and the PM10 concentration measured at 3m high exceeds 100μgm-3 while all the rest of QCM sampled data are classified as the dust advection case. The results indicate that the spectral mass concentration distribution of the local dust emission case shows a two-modal distribution with one additional mode of the large particle that cannot be resolved by the QCM cascade impactor whereas that of the advection case reveals a three-modal distribution with one additional unresolved large particle mode. The percent spectral mass concentration distribution of the unresolved mode (stage 1) for the local dust emission case is larger than that for the dust advection case. The modal distributions of both cases can be regressed optimally with log-normal distribution functions. The resolved log-normal distribution functions of the mass concentration distribution by the QCM cascade impactor are found to be the particle mean diameter (the standard deviation) of 0.28 (2.07) and 3.15μm (1.41μm) for the local emission case and 0.16 (1.51), 0.60 (1.41) and 2.88μm (1.38μm) for the advection case. This clearly suggests that the spectral mass concentration shifts toward the larger particle size for the local emission case. © 2013 Elsevier Ltd.


Jugder D.,Institute of Meteorology and Hydrology | Jugder D.,Tottori University | Shinoda M.,Tottori University | Sugimoto N.,Japan National Institute of Environmental Studies | And 5 more authors.
Global and Planetary Change | Year: 2011

Dust mass concentrations of PM10 and PM2.5 from four monitoring stations in the Gobi Desert region of Mongolia were analyzed for a 16-month period in 2009-2010. Annual averaged PM10 concentration ranged from 9μgm-3 to 49μgm-3 at these stations during 2009. Concentrations were high in winter owing to air pollution and in spring owing to dust storms; the monthly mean concentrations of PM10 (PM2.5) at the three stations except for Sainshand reached yearly maxima in December and January, ranging from 60 (38) μgm-3 to 120 (94) μgm-3. Diurnal variations of PM10 and PM2.5 concentrations at two sites, Dalanzadgad and Zamyn-Uud, included two maxima in the morning and evening and two minima in the afternoon and early morning. However, at Erdene PM10 maxima occurred in the afternoon and evening. Both PM10 and PM2.5 concentrations were enhanced from March to May by dust storms. Dust storms raised huge amounts of fine dust particles in the Gobi of Mongolia. Maximum daily mean PM10 (PM2.5) concentrations reached 821 (500) μgm-3 at Dalanzadgad, 308 (129) μgm-3 at Zamyn-Uud, and 1328μgm-3 at Erdene. Hourly maximum PM10 (PM2.5) concentrations were as high as 6626 (2899) μgm-3 at Dalanzadgad during a dust storm. © 2011 Elsevier B.V.


Park S.-U.,Center for Atmospheric and Environmental Modeling | Lee I.-H.,Center for Atmospheric and Environmental Modeling | Joo S.J.,Center for Atmospheric and Environmental Modeling
Science of the Total Environment | Year: 2016

Aerosol Modeling System (AMS) that is consisted of the Asian Dust Aerosol Model2 (ADAM2) and the Community Multi-scale Air Quality (CMAQ) modeling system has been employed to document the spatial distributions of the monthly and the annual averaged concentration of both the Asian dust (AD) aerosol and the anthropogenic aerosol (AA), and their total depositions in the Asian region for the year 2010. It is found that the annual mean surface aerosol (PM10) concentrations in the Asian region affect in a wide region as a complex mixture of AA and AD aerosols; they are predominated by the AD aerosol in the AD source region of northern China and Mongolia with a maximum concentration exceeding 300μgm-3; AAs are predominated in the high pollutant emission regions of southern and eastern China and northern India with a maximum concentration exceeding 110μgm-3; while the mixture of AA and AD aerosols is dominated in the downwind regions extending from the Yellow Sea to the Northwest Pacific Ocean. It is also found that the annual total deposition of aerosols in the model domain is found to be 485Tg (372Tg by AD aerosol and 113Tg by AA), of which 66% (319Tg) is contributed by the dry deposition (305Tg by AD aerosol and 14Tg by AA) and 34% (166Tg) by the wet deposition (66Tg by AD aerosol and 100Tg by AA), suggesting about 77% of the annual total deposition being contributed by the AD aerosol mainly through the dry deposition process and 24% of it by AA through the wet deposition process. The monthly mean aerosol concentration and the monthly total deposition show a significant seasonal variation with high in winter and spring, and low in summer. © 2015 Elsevier B.V.


Park S.-U.,Center for Atmospheric and Environmental Modeling | Ahn H.-J.,Gwangju Institute of Science and Technology | Park M.-S.,Center for Atmospheric and Environmental Modeling
Theoretical and Applied Climatology | Year: 2010

The physical processes of the feedback mechanism of direct shortwave radiative forcing of the Asian dust aerosol on dust emission has been examined using simulated results with the coupled (with dust shortwave radiative forcing) and the non-coupled model (without dust shortwave radiative forcing) based on the MM5 model and the Asian Dust Aerosol Model on 19 March 2002. The results indicate that a significant dust emission reduction occurs in the high dust concentration (HDC) region of the dust source region whereas an enhanced dust emission appears in the downstream of the dust source region. It is found that Asian dust aerosols raised during the daytime by the strong surface wind cause negative shortwave radiative flux near the surface, which in turn reduces the sensible heat flux causing the cooling of the air, thereby enhancing stable stratification. The dynamic adjustment of the negative radiative flux of the dust induces a positive pressure anomaly over the HDC region and a negative pressure anomaly toward the synoptic low pressure center, resulting in a dipole shape of pressure anomaly field near the surface. The associated secondary circulation of this pressure anomaly together with the reduction of turbulent intensity due to the reduced sensible heat flux reduces the low-level wind speed thereby reducing dust emission in the upstream of the HDC region of the dust source region (Region I), while enhancing the low-level wind speed in the downstream region (Region II), which in turn enhances dust emission. This enhanced dust emission is smaller than the emission reduction in the upstream, resulting in overall dust emission reduction during the daytime. © 2010 Springer-Verlag.


Park S.-U.,Center for Atmospheric and Environmental Modeling | Lee I.-H.,Center for Atmospheric and Environmental Modeling | Ju J.-W.,Center for Atmospheric and Environmental Modeling | Joo S.J.,Center for Atmospheric and Environmental Modeling
Journal of Environmental Radioactivity | Year: 2016

A methodology for the estimation of the emission rate of 137Cs by the Lagrangian Particle Dispersion Model (LPDM) with the use of monitored 137Cs concentrations around a nuclear power plant has been developed. This method has been employed with the MM5 meteorological model in the 600 km × 600 km model domain with the horizontal grid scale of 3 km × 3 km centered at the Fukushima nuclear power plant to estimate 137Cs emission rate for the accidental period from 00 UTC 12 March to 00 UTC 6 April 2011. The Lagrangian Particles are released continuously with the rate of one particle per minute at the first level modelled, about 15 m above the power plant site. The presently developed method was able to simulate quite reasonably the estimated 137Cs emission rate compared with other studies, suggesting the potential usefulness of the present method for the estimation of the emission rate from the accidental power plant without detailed inventories of reactors and fuel assemblies and spent fuels. The advantage of this method is not so complicated but can be applied only based on one-time forward LPDM simulation with monitored concentrations around the power plant, in contrast to other inverse models. It was also found that continuously monitored radionuclides concentrations from possibly many sites located in all directions around the power plant are required to get accurate continuous emission rates from the accident power plant. The current methodology can also be used to verify the previous version of radionuclides emissions used among other modeling groups for the cases of intermittent or discontinuous samplings. © 2016 Elsevier Ltd.


Park S.-U.,Center for Atmospheric and Environmental Modeling | Ju J.-W.,Center for Atmospheric and Environmental Modeling | Lee I.-H.,Center for Atmospheric and Environmental Modeling | Joo S.J.,Center for Atmospheric and Environmental Modeling
Atmospheric Environment | Year: 2016

The optimal regression equations for the dust emission flux parameterized with the friction velocity (u*) only, the friction velocity with the threshold friction velocity (u*t) and the friction velocity together with the flux Richardson number (Rf) in the dust source region are derived using the sonic anemometer measured momentum and kinematic heat fluxes at 8 m height and the two-level (3 m and 15 m height) measured PM10 concentrations from a 20-m monitoring tower located at Naiman in the Asian dust source region in China for the period from March 2013 to November 2014. The analysis period is divided into three sub-periods based on the Normalized Difference Vegetation Index (NDVI) to eliminate the effect of vegetation on the dust emission flux. The dust event is identified as a peak half hourly mean dust concentration (PM10) at 3 m height exceeding the sub-period mean dust concentration plus one standard deviation of the sub-period. The total of 317 dust events is identified with the highest number of dust event of 18.8 times a month in summer. The optimal regression equations of the dust emission flux (Fc) for dust events parameterized with u* and Rf are found to simulate quite well the dust emission flux estimated by the observed data at the site for all periods especially for the unstable stratification, suggesting the potential usefulness of these equations parameterized by u* with Rf rather than those by u* only and u* together with u*t for the estimation of the dust emission flux in the Asian dust source region. © 2016 Elsevier Ltd


Park M.-S.,Center for Atmospheric Science and Earthquake Research | Joo S.J.,Center for Atmospheric and Environmental Modeling | Park S.-U.,Center for Atmospheric and Environmental Modeling
Advances in Atmospheric Sciences | Year: 2014

The carbon dioxide (CO2) concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 to January 2012 were analyzed. The annual mean CO2 concentration was found to be 750 mg m-3, with a maximum monthly mean concentration of 827 mg m-3 in January and a minimum value of 679 mg m-3 in August. Meanwhile, the annual mean CO2 flux was found to be 0.45 mg m-2 s-1, with a maximum monthly mean flux of 0.91 mg m-2 s-1 in January and a minimum value of 0.19 mg m-2 s-1 in June. The hourly mean CO2 concentration was found to show a significant diurnal variation; a maximum at 0700-0900 LST and a minimum at 1400-1600 LST, with a large diurnal range in winter and a small one in summer, mainly caused by diurnal changes in mixing height, CO2 flux, and surface complexity. The hourly mean CO2 flux was also found to show a significant diurnal variation, but it showed two maxima at 0700-0900 LST and 2100-2400 LST, and two minima at 1100-1500 LST and 0300-0500 LST, mainly caused by a diurnal pattern in CO2 emissions and sinks from road traffic, domestic heating and cooking by liquefied natural gas use, and the different horizontal distribution of CO2 sources and sinks near the site. Differential advection with respect to wind direction was also found to be a cause of diurnal variations in both the CO2 concentration and flux. © 2014 Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.


Park M.-S.,Center for Atmospheric and Environmental Modeling | Joo S.J.,Center for Atmospheric and Environmental Modeling | Lee C.S.,Seoul Womens University
Advances in Atmospheric Sciences | Year: 2013

The CO2 concentrations and fluxes over an urban forest site (Namsan) and an urban residential region (Boramae) in Seoul, Korea, during the non-growing season (2-4 March 2011), the growing season (10-12 June 2011), and the late-growing season (22-24 September 2011) were analyzed. The CO2 concentrations of two sites showed nearly the same diurnal variation, with a maximum value occurring during the night and a minimum value occurring during daytime, as well as the same seasonal variation, with a maximum value during the non-growing season (early spring) and a minimum value during the growing season (summer). The CO2 flux over the urban forest did not show any typical diurnal variation during the non-growing season, but did show diurnal variation with a small positive value during the night and a large negative value during daytime in the growing and late-growing seasons due to photosynthesis in the urban forest. The CO2 flux over the urban residential region showed a positive daily mean value for all periods, with large values during the non-growing season and small values during the growing season, and it also showed diurnal variation with two maxima at 0600-1000 LST and 1800-2400 LST, and two minima at 0300-0600 LST and 1100-1500 LST, and was strongly correlated with the use of liquefied natural gas for cooking and heating by surrounding houses. © 2013 Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.


Park S.-U.,Center for Atmospheric and Environmental Modeling
Atmospheric Environment | Year: 2015

Aerosol Modeling System (AMS) that is consisted of the Asian Dust Aerosol Model2 (ADAM2) and the Community Multi-scale Air Quality (CMAQ) modeling system has been employed to document the geographical distributions of both the annual averaged Asian dust aerosol and the anthropogenic aerosols concentrations and their total depositions in the East Asia region for the year 2010. It is found that AMS simulates quite well the monitored PM10 concentration with a root mean square error (RMSE) of 9.2μgm-3 and a normalized mean square error (NMSE) of 5.5% in South Korea and the RMSE of less than 33μgm-3 with a NMSE of less than 7.8% at the monitoring sites in China. The annual mean surface (column integrated) aerosol concentrations in the East Asia region affect in a wide region as a complex mixture of the Asian dust (AD) aerosol and the anthropogenic aerosol (AA), more predominated by the AD aerosol in the Asian dust source region of northern China and Mongolia with the annual mean (column integrated) PM10 concentration of more than 200μgm-3 (350mgm-2). Whereas AA is dominated in the high pollutant emission regions of southern and eastern China and northern India with the annual mean surface (column integrated) concentration of more than 110μgm-3 (140mgm-2) in eastern China. On the other hand the mixed aerosols (AD+AA) are dominated in the downwind regions of the Yellow Sea, the East China Sea, the Korean peninsula, Japan, and the Northwest Pacific Ocean. It is also found that the annual total deposition of aerosols in the model domain is 4.9×108t (3.7×108t by AD aerosol and 1.2×108t by AA), of which 66% (3.2×108t) is found to be contributed by the dry deposition (3.1×108t by AD aerosol and 1.3×107t by AA) and 34% (1.7×108t) by the wet deposition (1.0×108t by AA and 6.6×107t by AD aerosol), suggesting significant impacts of aerosols on environment and the terrestrial and marine eco-systems in East Asia. © 2015 Elsevier Ltd.


PubMed | Center for Atmospheric and Environmental Modeling
Type: | Journal: Journal of environmental radioactivity | Year: 2016

A methodology for the estimation of the emission rate of

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