• 한국대기환경학회지
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• 제29권5호
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• pp.682-691
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• 2013

The aerosol extinction vertical profile and surface visibility have been derived from the Microtops-II sunphotometer observation during the winter 2011 intensive observation period (IOP) at Seoul, Korea. Using models of degradation of aerosol optical thickness (AOT) and aerosol scale height, we have performed extinction-visibility modulation to determine the height dependent aerosol extinction and visibility. It is shown that the aerosol loading is relatively low during IOP (mean $AOT_{550}=0.22{\pm}0.08$, ${\AA}$ngstr$\ddot{o}$m exponent=$1.14{\pm}0.26$). Modeled extinction by use of Microtops II sunphotometer data shows good agreement with measurements by the Multi-wavelenth Polarization Lidar (MPoLAR), and the derived surface visibility are consistent with data from the transmissometer. These results emphasize the use of a vertically resolved extinction from AOT to predict visibility conditions at ground level.

• 한국대기환경학회지
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• 제28권2호
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• pp.159-171
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• 2012

Aerosol direct radiative forcing (ADRF) retrieval method was developed by combining data from passive and active satellite sensors. Aerosol optical thickness (AOT) retrieved form the Moderate Resolution Imaging Spectroradiometer (MODIS) as a passive visible sensor and aerosol vertical profile from to the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) as an active laser sensor were investigated an application possibility. Especially, space-born Light Detection and Ranging (Lidar) observation provides a specific knowledge of the optical properties of atmospheric aerosols with spatial, temporal, vertical, and spectral resolutions. On the basis of extensive radiative transfer modeling, it is demonstrated that the use of the aerosol vertical profiles is sensitive to the estimation of ADRF. Throughout the investigation of relationship between aerosol height and ADRF, mean change rates of ADRF per increasing of 1 km aerosol height are smaller at surface than top-of-atmosphere (TOA). As a case study, satellite data for the Asian dust day of March 31, 2007 were used to estimate ADRF. Resulting ADRF values were compared with those retrieved independently from MODIS only data. The absolute difference values are 1.27% at surface level and 4.73% at top of atmosphere (TOA).

• Asian Journal of Atmospheric Environment
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• 제10권1호
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• pp.13-21
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• 2016

The vertical distributions of aerosol extinction coefficient were estimated using the scaling height retrieved at Gwangju, Korea ($35.23^{\circ}N$, $126.84^{\circ}E$) during a spring season (March to May) of 2009. The aerosol scaling heights were calculated on a basis of the aerosol optical depth (AOD) and the surface visibilities. During the observation period, the scaling heights varied between 3.55 km and 0.39 km. The retrieved vertical profiles of extinction coefficient from these scaling heights were compared with extinction profile derived from the Light Detection and Ranging (LIDAR) observation. The retrieve vertical profiles of aerosol extinction coefficient were categorized into three classes according to the values of AODs and the surface visibilities: (Case I) the AODs and the surface visibilities are measured as both high, (Case II) the AODs and the surface visibilities are both lower, and (Others) the others. The averaged scaling heights for the three cases were $3.09{\pm}0.46km$, $0.82{\pm}0.27km$, and $1.46{\pm}0.57km$, respectively. For Case I, differences between the vertical profile retrieved from the scaling height and the LIDAR observation was highest. Because aerosols in Case I are considered as dust-dominant, uplifted dust above planetary boundary layer (PBL) was influenced this discrepancy. However, for the Case II and other cases, the modelled vertical aerosol extinction profiles from the scaling heights are in good agreement with the results from the LIDAR observation. Although limitation in the current modelling of vertical structure of aerosols exists for aerosol layers above PBL, the results are promising to assess aerosol profile without high-cost instruments.

• 대한원격탐사학회지
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• 제29권3호
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• pp.325-329
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• 2013

This present study describes an application of UV scanning spectrometer $O_4$ data for retrieval of aerosol vertical profiles in Seoul during the measurement period that includes two Asian dust event days. The results show large variations of aerosol load in vertical and temporal scales. Large variations in aerosol were observed at 1 km in height during the daytime in the measurement period when the Asian dust events took place. The aerosol load, however, was found to be largest at the surface compared to those retrieved at the higher atmospheric layers. The results also clearly identified the diurnal patterns of aerosol vertical distributions. The aerosol load was high in the morning and noon whereas it was low in the afternoon. This study demonstrates that UV scanning spectrometer observations of the oxygen dimer can serve as a potential method for determination of atmospheric aerosol vertical distributions and optical properties.

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1172-1174
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• 1998

Spatial(radial and height) distributions of excited argon species are measured for an inductively coupled plasma under five operating conditions: 1) no carrier gas, 2) carrier gas without aerosol, 3) carrier gas with desolvated aerosol, 4) carrier gas with aerosol, 5) carrier gas with aerosol and excess lithium. A complete RF power mapping of argon excited states is obtained. The excited states of argon for a typical analytical torch rapidly diffuse towards the center in the higher region of the plasma. The presence of excess lithium makes no significant change in the excited states of argon. The increase in the RF power increases the intensity of argon excited states uniformly across the radial coordinate.

• Journal of the Optical Society of Korea
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• 제15권1호
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• pp.90-95
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• 2011

12-year LIDAR observations of tropospheric aerosol vertical distribution using a Mie scattering LIDAR in Hefei ($31.9^{\circ}N$, $117.2^{\circ}E$) from 1998 to 2009 are presented and analyzed in this paper. Characters of temporal variation and vertical distribution of tropospheric aerosol over Hefei are summarized from the LIDAR measurements. The impacts of natural source and human activities on the aerosol vertical distribution over Hefei could be seen clearly. Dust particles from the north in spring could affect the aerosol distributions below about 12 km over Hefei, and aerosol scale height in April reaches $2.29{\pm}0.68\;km$. Both LIDAR measurements and surface visibility imply that aerosols in the lower troposphere have been increasing since about 2005.

• Current Optics and Photonics
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• 제2권2호
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• pp.119-124
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• 2018

The errors in retrieved aerosol backscattering coefficients due to different lidar ratios are analyzed quantitatively in this paper. The actual calculation shows that the inversion error of the aerosol backscattering coefficients using the Fernald backward-integration method increases with increasing inversion distance. The greater the error in the lidar ratio, the faster the error in the aerosol backscattering coefficient increases. For the same error in lidar ratio, the smaller actual aerosol backscattering coefficient will get the larger relative error of the retrieved aerosol backscattering coefficient. The errors in the lidar ratios for dust or the cirrus layer have great impact on the retrievals of backscattering coefficients. The interval between the retrieved height and the reference range is one of the important factors for the derived error in the aerosol backscattering coefficient, which is revealed quantitatively for the first time in this paper. The conclusions of this article can provide a basis for error estimation in retrieved backscattering coefficients of background aerosols, dust and cirrus layer. The errors in the lidar ratio of an aerosol layer influence the retrievals of backscattering coefficients for the aerosol layer below it.

• 분석과학
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• 제8권4호
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• pp.411-418
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• 1995

A method for the direct determination of elemental content in each of aerosol particles by inductively coupled plasma atomic emission (ICP-AES) or mass spectrometry (ICP-MS) is described. This method is based upon the introduction of diluted aerosol into an ICP and the measurement of either the flash emission intensities of an atomic spectral line or ion intensities. A pulse-height analyzer is used for the measurement of the distribution of the elemental content. In order to calibrate the measuring system, monodisperse aerosols are used. The potentials of the method are shown by demonstrating the copper emission signals from the aerosols generated at a small electric switch, a study of the relation between the decreasing rate of particle number density and particle size, and measurements of calcium contents in the individual biological cells.

• 대한원격탐사학회지
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• 제36권2_1호
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• pp.155-165
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• 2020

본 연구에서는 복사전달모델을 사용하여 다양한 변수환경(파장 (340 nm, 477 nm), 에어로솔 종류(스모크, 황사, 황산염), AOD (aerosol optical depth), 지표면 반사도, 관측기하)에 따라 에어로솔 유효 고도(aerosol peak height; APH)에 대한 O₄ 대기질량인자(air mass factor; AMF)의 민감도를 조사하였다. 전반적으로, 477 nm의 O₄ AMF 가 340 nm 보다 APH에 대한 민감도가 크고 안정적으로 산출 가능한 것으로 확인하였다. AOD가 높을 때 APH에 대한 O₄ AMF의 민감도가 커지는 것을 확인하였다. 477 nm에서는 340 nm 보다 지표면 반사도의 영향이 큰 것으로 나타났다. 태양천정각 증가에 따라 340 nm에서의 O₄ AMF가 감소하는 추세를 발견하였으며, 이러한 경향은 태양천정각 40°인 환경에서 높은 Rayleigh 및 Mie 산란에 의한 장벽효과로 인해 O₄ 흡수가 발생하는 광경로 길이가 줄어들기 때문인 것으로 사료된다. 477 nm에서는 태양천정각이 증가함에 따라 Rayleigh 및 Mie 산란에 의한 다중산란이 일부 발생하여 O₄ AMF가 비선형함수 형태로 증가하는 경향을 보였다. 마지막으로, AOD의 불확실성이 APH 산출오차에 미치는 영향을 조사하였다. 황산염 타입에 대한 APH 산출 시, AOD의 불확실성으로 인한APH 산출오차가 다른 에어로솔 타입보다 크게 나타났으며, 황사의 경우 AOD 불확실성에 대한 APH 산출오차에 대한 영향이 미미하게 나타났다. 이러한 결과는 각 에어로솔 타입의 흡수 산란 특성이 다양하기 때문에, 에어로솔 타입이 APH 산출 오차에 영향을 미칠 수 있음을 의미한다.

• 한국입자에어로졸학회지
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• 제5권3호
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• pp.111-122
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• 2009

This paper reviews about synthesis of nanoparticles by spark discharge and applications. A method of catalytic activation with Pd and Pt aerosol nanoparticles produced by spark discharge was introduced. After annealing, the catalytically activated substrate placed into a solution for electroless silver deposition. The silver was then formed only on the activated regions of the substrate. Silver line patterns having a width of $18{\mu}m$ and a height of $1{\mu}m$ were created with the ability to be effectively reproduced. Antimicrobial nanoparticles such as silver were used for removal of bioaerosols. Silver nanoparticles deposited air filters such as ACF filters were evaluated by antimicrobial test.