基于综合立体观测网的京津冀地区污染过程分析

Pollution Process in Beijing-Tianjin-Hebei and Its Surrounding Areas Based on Comprehensive Stereoscopic Observation Network

为揭示大气污染的演变规律,推动京津冀及周边地区空气质量的持续改善,针对大气重污染发生—演变—消散全过程的核心科学问题,在京津冀及其周边地区建立大气污染传输通道立体观测网,围绕2017年秋冬季和2018年春、秋、冬三季开展重污染时段和重污染过程的地基和车载走航观测,评估区域大气污染输送和城市间大气污染的相互传输量.结果表明:北京市污染呈明显的区域性特征,春季主要受区域不利扩散条件及沙尘传输影响,秋季主要受西南通道传输影响,冬季主要受西南、南部、东南通道混合层内传输与区域扩散条件不利的共同影响.秋冬季京津冀地区NO 2、SO 2污染物垂直柱浓度整体低于西南、东南和南部输送通道区域,当弱南风静稳天气条件主导时,北京市易受到污染物输送的影响,形成局域污染过程.研究显示,北京市重污染时段外来污染物各类尺度输送通道中,西南通道污染传输为主导,部分时段还受到东南和东部通道污染传输的影响.

In order to reveal the evolution of air pollution and promote the continuous improvement of air quality,a three-dimensional observation network was established in the Beijing-Tianjin-Hebei and its surrounding areas to address the core scientific issues about the occurrence,evolution and dissipation of heavy air pollution.In the autumn and winter of 2017,the spring,autumn and winter of 2018,ground-based remote sensing of heavy pollution periods and processes autumn and vehicle-nounted navigation observations were carried out to evaluate the regional air pollution transport and the mutual spread of air pollution between cities.The results showed that the pollution in Beijing had obvious regional characteristics:in spring,it was mainly affected by the unfavorable regional diffusion conditions and dust transport;in autumn,it was mainly affected by the southwest channel transmission;in winter,it was mainly affected by the transport in the mixed layer of southwest,southern and southeast channels and regional diffusion conditions.In autumn and winter,the NO2 and SO2 pollutants in the Beijing-Tianjin-Hebei Region were lower than those in the southwest,southeast and southern transmission channels,and Beijing City was easily affected by the transportation of pollutants when the steady weather conditions of weak southerly wind dominated.According to the research,among the transport channels of various scales of foreign pollutants in Beijing,the southwest of the boundary layer was the main transport pathway,followed by the southeast and east channels.