Continuous vertical aerosol profiling with a multi-wavelength Raman polarization lidar over the Pearl River Delta, China
Birgit Heese1, Holger Baars1, Stephanie Bohlmann1, Dietrich Althausen1, and Ruru Deng21Leibniz Institute for Tropospheric Research (TROPOS), Permoserstrasse 15, 04318 Leipzig, Germany 2Sun Yat-sen University, Guangzhou, China
Received: 12 Aug 2016 – Accepted for review: 07 Oct 2016 – Discussion started: 11 Oct 2016
Abstract. A dataset of particle optical properties of the highly polluted atmosphere over the Pearl River Delta, Guangzhou, China, is presented in this paper. The data were derived from the measurements of a multi-wavelengths Raman and depolarization lidar PollyXT and a co-located AERONET sun photometer. The measurement campaign was conducted from November 2011 to mid June 2012. These are the first Raman lidar measurements in the PRD that were lasting for several months.
A mean value of aerosol optical depth observed by the sun photometer of 0.54 ± 0.33 was observed in the polluted atmosphere over this megacity for the whole measurement period. The lidar profiles frequently show lofted aerosol layers which reach up to altitudes of 2 to 3 km and especially in spring season up to even 5 km. These layers contain between 12 and 56 % of the total AOD, with the highest values in spring. The aerosol in these lofted layers were classified by their optical properties. The observed lidar ratio values are in the range from 30 to 80 sr with a mean value of 48.0 sr ± 10.7 sr. The linear particle depolarization ratio at 532 nm lied mostly below 5 % with a mean value of 3.6 ± 3.7. The majority of the Ångström exponents were observed between 1 and 1.5 indicating a coarse mode in addition to the fine mode in the particle size distribution.
These results reveal that mainly urban pollution particles mixed with particles arisen from biomass and industrial burning are present in the atmosphere above the Pearl River Delta. Trajectory analyses show that these pollution mixtures arise mainly from local and regional sources.
Heese, B., Baars, H., Bohlmann, S., Althausen, D., and Deng, R.: Continuous vertical aerosol profiling with a multi-wavelength Raman polarization lidar over the Pearl River Delta, China, Atmos. Chem. Phys. Discuss., doi:10.5194/acp-2016-733, in review, 2016.