Japan Geoscience Union Meeting 2018

Presentation information

[EJ] Oral

A (Atmospheric and Hydrospheric Sciences) » A-AS Atmospheric Sciences, Meteorology & Atmospheric Environment

[A-AS06] Atmospheric Chemistry

Thu. May 24, 2018 9:00 AM - 10:30 AM A05 (Tokyo Bay Makuhari Hall)

convener:Yoko Iwamoto(Graduate School of Biosphere Science, Hiroshima University), Tomoki Nakayama(Graduate School of Fisheries and Environmental Sciences, Nagasaki University), Sakae Toyoda(東京工業大学物質理工学院, 共同), Nawo Eguchi(Kyushu University), Chairperson:Ikeda Kohei(National Institute for Environmental Studies )

9:45 AM - 10:00 AM

[AAS06-09] Real-time observational evidence of changing Asian dust morphology with the mixing of heavy anthropogenic pollution

*Xiaole PAN1, Itsushi Uno2, Zhe WANG2, Tomoaki Nishizawa3, Nobuo Sugimoto3 (1.Institute of Atmospheric Physics/Chinese Academy of Sciences, 2.Research Institute of Applied Mechanism/Kyushu university, 3.National Institute for Environmental studies)

Keywords:mineral dust aerosol, depolarization ratio, heterogeneous reaction, anthropogenic pollutants

Natural mineral dust and heavy anthropogenic pollution and its complex interactions cause significant environmental problems in East Asia. Due to restrictions of observing technique, real-time morphological change in Asian dust particles owing to coating process of anthropogenic pollutants is still statistically unclear. Here, we first used a newly developed, single-particle polarization detector and quantitatively investigate the evolution of the polarization property of backscattering light reflected from dust particle as they were mixing with anthropogenic pollutants in North China. The decrease in observed depolarization ratio is mainly attributed to the decrease of aspect ratio of the dust particles as a result of continuous coating processes. Hygroscopic growth of Calcium nitrate (Ca(NO3)2) on the surface of the dust particles played a vital role, particularly when they are stagnant in the polluted region with high RH conditions. Reliable statistics highlight the signi cant importance of internally mixed, ‘quasi-spherical’ Asian dust particles, which markedly act as cloud condensation nuclei and exert regional climate change.