• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.97-109
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• 2007

Vertical distribution and optical properties of atmospheric aerosols above the Korean peninsula are quite important to estimate effects of aerosol on atmospheric environment and regional radiative forcing. For the first time in Korea, vertical microphysical properties of atmospheric aerosol obtained by inversion algorithm were analyzed based on optical data of multi-wavelength Raman lidar system developed by the Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST). Data collected on 14 June 2004 at Gwangju ($35.10^{\circ}N,\;126.53^{\circ}E$) and 27 May 2005 at Anmyeon island ($36.32^{\circ}N,\;126.19^{\circ}E$) were used as raw optical data for inversion algorithm. Siberian forest fire smoke and local originated haze were observed above and within the height of PBL, respectively on 14 June 2004 according to NOAA/Hysplit backstrajectory analysis. The inversion of lidar optical data resulted in particle effective radii around $0.31{\sim}0.33{\mu}m$, single scattering albedo between $0.964{\sim}0.977$ at 532 nm in PBL and effective radii of $0.27{\mu}m$ and single scattering albedo between $0.923{\sim}0.924$ above PBL. In the case on 27 May 2005, biomass burning from east China was a main source of aerosol plume. The inversion results of the data on 27 May 2005 were found to be particle effective radii between $0.23{\sim}0.24{\mu}m$, single scattering albedo around $0.924{\sim}0.929$ at 532 nm. Additionally, the inversion values were well matched with those of Sun/sky radiometer in measurement period.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.298-301
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• 2007

Vertical distribution and optical properties of atmospheric aerosols above the Korean peninsula are quite important to estimate effects of aerosol on atmospheric environment and regional radiative forcing. For the first time in Korea, vertical microphysical properties of atmospheric aerosol obtained by inversion algorithm were analyzed based on optical data of multi-wavelength Raman lidar system developed by the Advanced Environmental Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST). Data collected on 14 June 2004 at Gwangju ($35.10^{\circ}N$, $126.53^{\circ}E$) and 27 May 2005 at Anmyeon island ($36.32^{\circ}N$, $126.19^{\circ}E$) were used as raw optical data for inversion algorithm. Siberian forest fire smoke and local originated haze were observed above and within the height of PBL, respectively on 14 June 2004 according to NOAA/Hysplit backstrajectory analysis. The inversion of lidar optical data resulted in particle effective radii around 0.32 ${\mu}m$, single scattering albedo between 0.97 at 532 nm in PBL and effective radii of 0.27 ${\mu}m$ and single scattering albedo of 0.92 above PBL. In the case on 27 May 2005, biomass burning from east China was a main source of aerosol plume. The inversion results of the data on 27 May 2005 were found to be particle effective radii between 0.24 ${\mu}m$, single scattering albedo around 0.91 at 532 nm. Additionally, the inversion values were well matched with those of Sun/sky radiometer in measurement period.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.6
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• pp.688-696
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• 2012

The particle depolarization ratios were retrieved from the observation with a multi-wavelength Raman lidar at Gwangju, Korea ($35.11^{\circ}N$, $126.54^{\circ}E$). The measurements were carried out on 24 February and 9 March 2004. Using the particle depolarization ratios, the non-dust aerosol particles were distinguished from the Asian dust plume, and the proportion of the non-dust particle to total dust plume was retrieved. The calculated proportion of the non-dust particle was used for the retrieval of backscatter coefficients at 355, 532, and 1064 nm and extinction coefficients at 355 and 532 nm of non-dust particles in the dust plume. Microphysical parameters of non-dust particles including single-scattering albedo at 532 nm were retrieved using retrieved optical values. The retrieved single-scattering albedo of non-dust particles was 0.92~0.95 below 1 km height and 0.82~0.91 above 1 km height on 24 February 2004 and $0.81{\pm}0.03$ on 9 March 2004.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.71.2-71.2
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• 2010

We present the results of FUV dust scattering simulation, which is based on the Monte-Carlo method. In this simulation, we focus on the multiple scattering in the Ophiuchus complex region because the single scattering case in the region already reported by Lee et al. 2008. We compare the simulation result to the FUV intensity with FIMS and the single scattering result. We also discuss the parameters related to the results of this simulation, such as asymmetry factor, albedo and other different setting-ups.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.2
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• pp.40-45
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• 1992

A simple emission model applicable for low scattering (scattering << absorption) anisotropic layer is developed and applied to the interpretation of measurements of microwave emission from row crops. The vegetation layer of row crops is modeled as a random slab embedded with small spheroid with major axis aligend paralel to the crop-row direction. The total emission is given in a simple algebraic form based on the zero-order radiative transfer theory. The single scattering albedo for spheroid and its polarimetric phase function are presented. The effects of layer azimuthal dependence on emission are accounted for by using an anisotropic albedo in the zero-order transfer theory. The developed emission theory favorably compares with the brightness temperature measured over soybeans canopy.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.210.2-210.2
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• 2012

Using Fresnel reflection and Hapke BRDF model with Apollo 10084 soil sample's scattering properties, we constructed a real scale optical lunar model and used it to simulate lunar apparent albedo and moonshine. For Fresnel reflection, the refractive index of $1.68{\pm}0.5$ was used. For Hapke BRDF parameters from BUGs BRDF measurement, the single scattering with w=0.33, hot spot width h=0.017, average phase angle ${\zeta}$=-0.086 and Legendre polynomial coefficients b=0.308, c=0.425 in wavelength 700nm with two types of Henyey-Greenstein phase function was applied. The computation model includes the Sun as a Lambertian scattering sphere, emitting 1.5078 W/m2 at 700nm in wavelength. The Sun and Moon models were then imported into the IRT based radiative transfer computation. The trial simulation of the irradiance levels of moonshine lights shows that they agree well with the ROLO measurement data. We then estimate the lunar apparent albedo to 0.11. The results are to be compared with the measurement data.

• 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%.

• Atmosphere
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• v.23 no.1
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• pp.39-45
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• 2013

A parameterization for the scattering of longwave radiation by ice clouds has been developed based on spectral scattering property calculations with shapes and sizes of ice crystals. For this parameterization, the size distribution data by Fu (1996) and by Michell and Arnott (1994) are used. The shapes of ice crystal considered in this study are plate, solid column, hollow column, bullet-rosette, droxtal, aggregate, and spheroid. The properties of longwave scattering by ice crystals are presented as a function of the extinction coefficient, single-scattering albedo, and asymmetry factor. The heating rate and flux by the radiative parameterization model are calculated for wide range of ice crystal sizes, shapes, and optical thickness. The results are compared with the calculated results using a six-stream discrete ordinate scattering algorithm and Chou's method. The new method (with various habits and size distributions) provides a good simulation of the scattering properties and cooling rate in optically thin clouds (optical thickness < 5). Depending on the inclusion of scattering by ice clouds, the errors in the calculation of the cooling rates are significantly different.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.12-16
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• 2002

The clear sky radiative forcings of aerosols were evaluated over East Asia. We first investigated optical characteristics of aerosol using sky radiation measurements. An algorithm of Nakajima et al. (1996) is used for retrieving aerosol parameters such as optical thickness, ${\AA}$ngstr$\"{O}$m exponent, single scattering albedo, and size distribution from sky-radiation measurements, which then can be used for examining spatial and temporal variations of aerosol. Obtaining aerosol radiative forcing at TOA and surface, a radiative transfer model is used with inputs of obtained aerosol parameters and GMS-5 satellite-based cloud optical properties. Results show that there is a good agreement of simulated downwelling radiative flux at the surface with observation within 10 W m$^{-2}$ rms errors under the clear sky condition. However, a relatively large difference up to 40 W m$^{-2}$ rms error is found under the cloudy sky condition. The computed aerosol radiative forcing at the surface shows downward flux changes ranging from -100 to -170 W m$^{-2}$ per unit aerosol optical thickness at 0.7 $\mu$m. The different values of aerosol radiative forcing among the stations is mainly due to the differences in single scattering albedo ($\omega$$_{0.7}$) and asymmetric parameter (g$_1$) related to the geographical and seasonal variations.

• Korean Journal of Remote Sensing
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• v.29 no.4
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• pp.415-421
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• 2013

A new approach to retrieve the single-scattering albedo (SSA) of Asian dust plume, mixed with pollution particles, using multi-wavelength Raman lidar system was suggested in this study. Asian dust plume was separated as dust and non-dust particle (i.e. spherical particle) by the particle depolarization ratio at 532 nm. The vertical profiles of optical properties (the particle extinction coefficient at 355 and 532 nm and backscatter coefficient at 355, 532 and 1064 nm) for non-dust particle were used as input parameter for the inversion algorithm. The inversion algorithm provides the vertical distribution of microphysical properties of non-dust particle only so that the estimation of the SSA for the Asian dust in mixing state was suggested in this study. In order to estimate the SSA for the mixed Asian dust, we combined the SSA of non-dust particles retrieved by the inversion algorithms with assumed the SSA of 0.96 at 532 nm for dust. The retrieved SSA of Asian dust plume by lidar data was compared with the Aerosol Robotics Network (AERONET) retrieved values and showed good agreement.