西太平洋台风“苏迪罗”对我国珠三角地区臭氧污染影响研究

Study on the Impact of Western Pacific Typhoon Soudelor on Ozone Pollution in Pearl River Delta Region, Southern China

通过资料分析和数值模拟开展了2015年8月1日-10日台风“苏迪罗”对珠三角地区臭氧(O3)污染影响的机理研究。结果表明,2015年8月5—8日,在台风接近登陆点的过程中,台风外围天气导致了高温、高辐射和静小风等气象条件,促进了光化学反应的进行和污染物的局地积累。同时,高温、高辐射等气象条件加剧了植被源区生物源挥发性有机物(BVOCs)的排放。采用化学传输模式模拟发现,植被BVOCs对O3污染的贡献最高可达24×10-9。结合拉格朗日粒子扩散模式(LPDM)探索了影响珠三角地区的主导气团,发现珠三角城市地区和高BVOCs源区存在交互传输的现象。污染期间,高BVOCs源区的一次排放产物(BVOCs)和二次产物(O3)经区域输送加剧了珠三角地区O3的污染。此外,研究发现台风外围条件下珠三角内陆盛行的偏北风与海陆热力差异引起的海风在沿海地区辐合,造成污染物局地积累,加剧并延长了O3污染。研究有利于加强对O3污染机理的认识,进而更好地采取针对性措施,有助于减小O3污染带来的危害。

This study combined data analysis and numerical simulations with the aim to study the impact of Typhoon Soudiro(August 1 to August 10 in 2015) on ozone pollution in the Pearl River Delta(PRD) region, a highly developed city clusters in southern China. The results showed that the typhoon periphery weather resulted in a stagnant weather with high temperature, high radiation and light wind, which led to the progress of photochemical reaction and the local accumulation of pollutants. Meanwhile, high temperature, high radiation and other meteorological conditions aggravated the emission of BVOCs(biogenic volatile organic carbons) in the vegetation area. The contribution of BVOCs could reach up to 24×10-9by using a chemical transport model. The study also investigated the dominant air masses in PRD using the Lagrangian particle diffusion model. The results found that there was an interactive transportation between the urban area and the remote high BVOCs source area. The regional transportation of primary emissions(BVOCs) and secondary products(O3) from the remote area exacerbates the ozone pollution in the urban area of PRD. In addition, the convergence of the northerly prevailing wind in the inland and the southerly sea breeze resulted in the local accumulation of pollutants and prolonging ozone pollution in the coastlines. This study contributes to strengthen the understanding of ozone pollution in China, so as to take proper measurements to reduce the harm of ozone pollution.