Vertical profiling of Asian dust with multi-wavelength aerosol depolarization Raman lidar in Gwangju, Korea during DRAGON

The Distributed Regional Aerosol Gridded Observation Networks (DRAGON) campaign, which was carried out in Korea from March to May 2013, aimed at validating satellite remote sensing data of aerosol optical and microphysical parameters. Anthropogenic pollution and Asian dust from the East Asian Mainland prevailed over the Korean peninsula during the DRAGON campaign. Validation of the data products requires knowledge on the vertical distribution of aerosol pollution and the knowledge of aerosol types, e.g., urban haze and dust. For this purpose we operated a multi-wavelength aerosol depolarization Raman lidar on the campus of the Gwangju Institute of Science and Technology (GIST) in Gwangju, Korea (35.10° N, 126.53° E). The system provides us with particle backscatter coefficients at 355, 532 and 1064 nm, extinction coefficients at 355 and 532nm, and the linear particle depolarization ratio at 532nm. Two upgraded sun photometers of the Aerosol Robotic Network (AERONET) with improved capabilities for dust measurements were also deployed. In our contribution we will present optical properties of Asian dust on the basis of lidar and sun photometer observations. One sun photometer was equipped with a measurement channel at 1640 nm channel and the second sun photometer carried out polarization measurements. Data could be collected on thirty-eight days We analyzed the geometrical and optical properties of Asian dust on the basis of backward trajectories in order to identify the main source regions of the observed dust layers. The height resolved statistical analysis of the DRAGON dataset reveals that the geometrical depth of the Asian dust layers was between 1 km and 4 km in 72% of all cases. Geometrical depths above 4 km were found in 20% of all cases. We found geometrical depths of 10 km in 3.3% of all cases. The vertical distribution of the dust layers was typically located in two different heights. In 51.5% of the measurements we observed Asian dust between 4 and 11km height above sea level. In 48.5% of the cases dust was below 4 km height above sea level.