[A floating-dust case study based on the vertical distribution of aerosol optical properties]

The vertical distribution of aerosol optical properties of a typical floating-dust event on October 19, 2009 in Shanghai was analyzed by using Micro-pulse Lidar (MPL) and the CALIPSO satellite. The results showed that the floating-dust aerosol mainly existed below 2 km of height. The floating-dust aerosol backscatter coefficient ranged from 0 to 0.015 km(-1) x sr(-1), and the MPL extinction coefficient ranged from 0 to 0.32 km(-1). The MPL data showed that the aerosol extinction coefficient first increased and then decreased during the floating-dust event. At the same time, the aerosol layer was constantly lifting. The CALIPSO data showed that a large number of small particles were suspended in air at a height of below 2 km, while the big particles always stayed near the ground (0-0.5 km). At the height of 2-10 km, there was only few aerosols; in the range of 4-6 km, there was a mixture of particles with regular and irregular shapes. The vertical distribution of CALIPSO 532 nm total attenuated backscatter coefficient and MPL normalized relative backscatter signal was basically the same, but the extinction coefficient values gained by them were different. Observations by CALIPSO and MPL together could be more comprehensive and objective for monitoring floating-dust in Shanghai.