• Journal of Korean Society for Atmospheric Environment
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• v.33 no.5
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• pp.458-472
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• 2017

The optical properties and direct aerosol radiative forcing (DARF) of different aerosol components in $PM_{2.5}$ (water-soluble, insoluble, black carbon (BC), and sea-salt) were estimated using the hourly resolution data measured at Aewol intensive air monitoring site on Jeju Island during 2013, based on a modeling approach. In general, the water-soluble component was predominant over all other components with respect to its impact on the optical properties(except for absorbing BC) and DARF. The annual mean aerosol optical depth (AOD) at 500 nm for the water-soluble component was $0.14{\pm}0.14$ ($0.04{\pm}0.01$ for BC). The total DARF at the surface ($DARF_{SFC}$) and top of the atmosphere ($DARF_{TOA}$), and in the atmosphere ($DARF_{ATM}$) for most aerosol components(except for sea-salt) during the daytime were highest in spring and lowest in fall and/or summer. The maximum $DARF_{SFC}$ of most aerosol components occurred around noon (12:00~14:00 LST) during all seasons, while the maximum $DARF_{TOA}$ occurred in the afternoon (13:00~16:00 LST) during most seasons (except for spring). In addition, the estimated $DARF_{SFC}$ and $DARF_{ATM}$ of the water-soluble component were -20 to $-59W/m^2$ and +3.5 to $+14W/m^2$, respectively, while those of BC were -18 to $-29W/m^2$ and +23 to $+37W/m^2$, respectively.

• Asian Journal of Atmospheric Environment
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• v.6 no.4
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• pp.304-313
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• 2012

In this study, the ${\AA}$ngstrom exponent for polydispersed aerosol during dynamic processes was investigated. Log-normal aerosol size distribution was assumed, and a sensitivity analysis of the ${\AA}$ngstrom exponent with regards the coagulation and condensation process was performed. The ${\AA}$ngstrom exponent is expected to decrease because of the particle growth due to coagulation and condensation. However, it is difficult to quantify the degree of change. In order to understand quantitatively the change in the ${\AA}$ngstrom exponent during coagulation and condensation, different real and imaginary parts of the refractive index were considered. The results show that the ${\AA}$ngstrom exponent is sensitive to changes in size distribution and refractive index. The total number concentration decreases and the geometric mean diameter of aerosols increase during coagulation. On the while, the geometric standard deviation approaches monodispersed size distribution during the condensation process, and this change in size distribution affects the ${\AA}$ngstrom exponent. The degree of change in the ${\AA}$ngstrom exponent depends on the refractive index and initial size distribution, and the size parameter changes with the ${\AA}$ngstrom exponent for a given refractive index or chemical composition; this indicates that the size distribution plays an important role in determining the ${\AA}$ngstrom exponent as well as the chemical composition. Subsequently, this study shows how the ${\AA}$ngstrom exponent changes quantitatively during the aerosol dynamics processes for a log-normal aerosol size distribution for different refractive indices; the results showed good agreement with the results for simple analytic size distribution solutions.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.2
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• pp.90-97
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• 1994

PIXE( Proton Induced X- ray Emission ) analysis has been applied to the analysis of aerosol for the Purpose of pollution monitoring. Coarse and fine Particle fractions were sampled selectively, using Nuclepore filter in stacked filter units, once a month from February to September in 1993 at urban and rural sites. Concentration of 9 elements, Si, S, K, Ca, Mn, Fe, Cu, Zn and Pb was determined without Pretreatment of Samples. Comparison of data between urban and rural site revealed higher elemental concentration level in urban aerosol. From April to May aerosol sampling was carried out daily to observe the effect of Yellow Sand on the composition of aerosol in the Korean Peninsula. During the Yellow Sand period, Si, Ca, Fe content level in aerosol became more than 5 times higher than normal. The elemental concentration of the aerosol samples of Daejeon City was compared with that of two foreign cities. S and Pb( which are fuel- derived elements) levels in Daejeon City aerosol appeared to be lower than those of foreign cities. And it may be due to the leaded-fuel restriction policy of Korean government since 1987.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.53-54
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• 2009

The influence of atmospheric aerosol on satellite ocean color data were evaluated using SeaWiFS monthly standard mapped image products. The atmospheric optical thickness (AOT) was increased in spring and summer, and it showed the strong positive correlation with remote sensing reflectance, normalized waterleaving radiance /solar irradiance, at 555 nm (Rrs555) which is a component of the satellite chlorophyll estimation. Such the high AOT and high Rrs555 pixels showed overestimation of satellite chlorophyll in spring, especially in the area which showed large phytoplankton absorption which 1s expressed by low remote sensing reflectance at 443, 490 and 510 nm (Rrs 443, Rrs490 and Rrs510).

• Asian Journal of Atmospheric Environment
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• v.8 no.2
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• pp.69-80
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• 2014

It is often assumed that atmospheric observations at remote sites represent long-range transport of airborne material, and local influences are overlooked. We evaluated the impact of local input on the rainwater composition at Gosan Station, a strategic site for monitoring the continental outflow from Asia. We analyzed a 14-year record of rainwater chemical composition archived by the Korea Meteorological Administration and detected local terrestrial contribution for nitrate, sulfate and ammonium. We also measured the chemical composition of rainwater sampled simultaneously at multiple locations within the premises of the Gosan Station, from which local influence with meter-scale spatial heterogeneity could be discerned. We estimate that the local input accounted for at least ~10% of the wet deposition of nitrogen and ~12% of the wet deposition of sulfur during the 14 years. This highlights the significance of the local influence, which should be carefully assessed when interpreting atmospheric observations at this site.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.5
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• pp.554-566
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• 2010

We present optical and microphysical particle properties of aerosol retrieved by multi-wavelength Raman lidar at Anmyun island ($36.32^{\circ}N$, $126.19^{\circ}E$), Korea. The results present aerosol properties in various height layers of the atmospheric pollution layers observed over the Korean peninsula on eight consecutive days (27, 28, 29, 30 and 31 May, 4, 5 and 7 June) in 2005 at Anmyun island. We found anthropogenic pollution on 27, 28, and 29 May and local haze on other measurement days. The origin of the particle plumes was determined by simulations of FLEXPART. The source regions of the particles resulted in rather clear differences between the optical and microphysical properties of the pollution layers. The single-scattering albedo of anthropogenic aerosols from China ($0.91{\pm}0.01$ at 532 nm) were lower than the single-scattering albedo of local haze aerosols ($0.95{\pm}0.01$ at 532 nm). Local haze aerosols show larger effective radii of $0.24{\pm}0.02\;{\mu}m$ at relative humidity of 55~75%. The effective radii of anthropogenic aerosols are $0.20{\pm}0.2\;{\mu}m$ and $0.27\;{\mu}m$ at relative humidity of 25~50%.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.65-66
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.523-524
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• 2005

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2006.04a
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• pp.290-292
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• 2006

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2007.10a
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• pp.411-413
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• 2007