Dongho Shin

Mineral quartz concentration measurements of mixed mineral dust/urban haze pollution plumes over Korea with multiwavelength aerosol Raman-quartz lidar.

[1]xa0We present a case study of a concentration measurement of mineral quartz immersed in East Asian urban pollution. We use a novel lidar measurement technique that uses signals from Raman scattering from quartz at ultraviolet (360 nm) wavelength. The particle-extinction-related Angstrom exponent (wavelength pair 355/532 nm) varies around 0.7 ± 0.2 , the lidar ratio is 50–55 sr at 532 nm. The numbers indicate that the pollution plume likely consisted of a mixture of mineral dust with urban haze. Dust concentrations vary between 8–11 μg/cm3. We determined Raman quartz concentrations from measurements simultaneously carried out at 546 nm, which allows us to measure for the first time the Raman-quartz-related Angstrom exponent of mineral dust. Values are 3–4, whereas we expect a theoretical value of 4. It is unclear if the lower values follow from retrieval uncertainties or if they are linked to the internal structure of the quartz grains.

Record heavy mineral dust outbreaks over Korea in 2010: Two cases observed with multiwavelength aerosol/depolarization/Raman‐quartz lidar

[1]xa0We report on two strong events of transport of mineral dust from Central Asia across Korea. The events took place in March and November 2010. The November case is important as fall is not a typical time for strong dust outbreaks in East Asia. We observed the dust with a multiwavelength aerosol/depolarization/Raman quartz lidar. The record PM-10 concentration of nearly 1600μg/m3 in March 2010 exceeds the record value of 1470 μg/m3 measured in Seoul in March 2002. The event in November was the strongest case of dust transport ever observed over Korea in fall. We find up to 360 μg/m3dust in heights above 250xa0m which is significantly different from the ground-based PM-10 observations.

The Retrieval of the Asian Dust Depolarization Ratio in Korea with the Correction of the Polarization-Dependent Transmission

The linear particle depolarization ratios were retrieved from the observation with a multiwavelength Raman lidar at the Gwangju Institute of Science and Technology (GIST), Korea (35.11°N, 126.54°E). The measurements were carried out in spring (March to May) 2011. The transmission ratio measurements were performed to solve problems of the depolarization-dependent transmission at a receiver of the lidar and applied to correct the retrieved depolarization ratio of Asian dust at first time in Korea. The analyzed data from the GIST multiwavelength Raman lidar were classified into three categories according to the linear particle depolarization ratios, which are pure Asian dust on 21 March, the intermediate case which means Asian dust mixed with urban pollution on 13 May, and haze case on 10 April. The measured transmission ratios were applied to these cases respectively. We found that the transmission ratio is needed to be used to retrieve the accurate depolarization ratio of Asian dust and also would be useful to distinguish the mixed dust particles between intermediate case and haze. The particle depolarization ratios of pure Asian dust were approximately 0.25 at 532 nm and 0.14 at 532 nm for the intermediate case. The linear particle depolarization ratios of pure Asian dust observed with the GIST multiwavelength Raman lidar were compared to the linear particle depolarization ratios of Saharan dust observed in Morocco and Asian dust observed both in Japan and China.

Retrieval of the Single Scattering Albedo of Asian Dust Mixed with Pollutants Using Lidar Observations

The vertical distribution of single scattering albedos (SSAs) of Asian dust mixed with pollutants was derived using the multi-wavelength Raman lidar observation system at Gwangju (35.10°N, 126.53°E). Vertical profiles of both backscatter and extinction coefficients for dust and non-dust aerosols were extracted from a mixed Asian dust plume using the depolarization ratio from lidar observations. Vertical profiles of backscatter and extinction coefficients of non-dust particles were input into an inversion algorithm to retrieve the SSAs of non-dust aerosols. Atmospheric aerosol layers at different heights had different light-absorbing characteristics. The SSAs of non-dust particles at each height varied with aerosol type, which was either urban/industrial pollutants from China transported over long distances at high altitude, or regional/local pollutants from the Korean peninsula. Taking advantage of independent profiles of SSAs of non-dust particles, vertical profiles of SSAs of Asian dust mixed with pollutants were estimated for the first time, with a new approach suggested in this study using an empirical determination of the SSA of pure dust. The SSAs of the Asian dust-pollutants mixture within the planetary boundary layer (PBL) were in the range 0.88–0.91, while the values above the PBL were in the range 0.76–0.87, with a very low mean value of 0.76±0.05. The total mixed dust plume SSAs in each aerosol layer were integrated over height for comparison with results from the Aerosol Robotics Network (AERONET) measurements. Values of SSA retrieved from lidar observations of 0.92±0.01 were in good agreement with the results from AERONET measurements.

Depolarization Ratio Retrievals Using AERONET Sun Photometer Data

We present linear particle depolarization ratios (LPDRs) retrieved from measurements with an AERONET Sun photometer at the Gwangju Institute of Science and Technology (GIST), Korea (lTEXg

Possibilities of the multichannel lidar spectrometer technique for investigation of the atmospheric aerosols and pollutions

35.10^{/circ}N

Investigation of the diurnal pattern of the vertical distribution of pollen in the lower troposphere using LIDAR

l/TEXg, lTEXg

Retrieval of the Variation of Optical Characteristics of Asian Dust Plume according to their Vertical Distributions using Multi -wavelength Raman LIDAR System

126.53^{circ}E

Retrieval of Vertical Single-scattering albedo of Asian dust using Multi-wavelength Raman Lidar System

l/TEXg) between 19 October and 3 November 2009. The Sun photometer data were classified into three categories according to lTEXg

Investigation of diurnal patterns in vertical distributions of pollen in the lower troposphere using LIDAR technique

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