Aerosol Size Distribution Measurement And Potential Sources&transport Of Mountain Huang

In this study, the particle number concentrations from2008to2012of Mt. Huang in different heights were observed. The particle size, size distribution, concentration characteristics in spring summer and autumn season were analyzed. The trajectories of air masses reaching the summit of Mt. Huang, during three seasons, and their relationship with the number concentration of accumulation mode particles are analyzed based on a clustering technique combined with in situ measurements of the number concentration of aerosol particles. The possible sources of the accumulation mode aerosol particles over the summit of Mt. Huang under different air mass conditions are analyzed qualitatively with the method of potential source contribution function (PSCF) and the method concentration weighted field (CWT). Finally, in order to simulate source and transport of accumulation mode aerosol particles over the summit of Mt. Huang, WRF model and FLEXPART model were used in this research.The results show that nucleation mode particles concentration accounted for most in spring, while the number concentrations of accumulation mode aerosol were highest in summer. The diurnal variation of aerosol concentration in three seasons were similar with a higher concentration appeared in afternoon than in morning, and meanwhile the peak value appeared at18:00(LST) everyday. Total mode particle concentration in the bottom of Mt. Huang observation point was2.4times higher than that at the summit observation point. However, the accumulation mode aerosol number concentration at the summit was higher than bottom. The diurnal variation at summit observation point presented a single peak distribution and the peak value appeared at18:00PM. Compared with summit observation results, the bottom diurnal variation presented a multi-peak distribution; the peak value appeared at7:00AM,11:00AM, and18:00PM. In the spring, the air mass from the northwest lead to a high number concentration of nucleation mode and Aitken mode aerosol, while the marine air mass from the northeast brought more accumulation mode aerosol. In the autumn, long-distance air mass from northwest was benefited to the nucleation mode aerosol. The PSCF and CWT results show that the potential sources of the accumulation mode particles over the summit of Mt. Huang are mainly from the most industrialized and heavily populated cluster of cities such as the eastern Hubei, central Anhui, Henan and Jiangxi province, the junction of Guangdong and Guangxi, southern Hunan and northern Zhejiang. The vertical cross sections show that the accumulation mode particles over Mt. Huang are mainly transported from the free troposphere with the heights between approximately2000m and5000m and originated from the northwest and southwest pathways. The WRF-FLEXPART results showed that summit observation aerosol were mainly from the northeast marine air mass, and from the southwest direction with high-level (>2000m). Compared with the02:00AM results, at14:00PM, the particle source scope were wider range of air mass, which was affected by the PBL change. The potential sources of the particles over the summit of Mt. Huang are mainly from Hunan, the junction of Zhejiang-Jiangxi and Anhui provinces, Hangzhou and Ningbo region.