【摘要】：利用大氣物理綜合觀測資料分析了2013年3月9日北京市一次沙塵過程前后的氣溶膠粒徑變化情況和垂直分布特性,比較了霾-沙交替的污染特征差異,并對沙塵來源及傳輸過程進(jìn)行解析.結(jié)果表明:沙塵開始前近地面為細(xì)顆粒物主導(dǎo)的干霾氣溶膠污染,該過程在污染物出現(xiàn)分層抬升擴(kuò)散后得到緩解,地面ρ(PM_(2.5))/ρ(PM_(10))最高達(dá)0.93.外源輸送抵達(dá)的浮塵分布在上空800~2500m范圍內(nèi),退偏振比平均0.35,明顯高于霾氣溶膠層.沙塵初期的鋒前大風(fēng)使邊界層抬升至900m以上,浮塵向下與本地?fù)P塵混合,使近地污染轉(zhuǎn)為以粗顆粒增加為主,揚(yáng)沙天氣爆發(fā),ρ(PM_(10))小時(shí)值增至920μg/m~3,退偏振比增至0.4,地面上3000m范圍均有沙塵粒子分布.冷鋒配合蒙古氣旋是造成此次沙塵的主要天氣系統(tǒng),不斷加深發(fā)展的高空槽和地面氣旋上升氣流為外蒙沙塵推進(jìn)和傳輸提供了動力條件.
[Abstract]:The variation of aerosol particle size and its vertical distribution characteristics before and after a dust process in Beijing on March 9, 2013 are analyzed by using the comprehensive observation data of atmospheric physics. The differences of pollution characteristics between haze and sand are compared, and the source and transmission process of dust are analyzed. The results show that the dry haze aerosol pollution dominated by fine particles is near the surface before the dust begins, and the process is alleviated after the stratification and diffusion of the pollutants, and the highest level of PM_ / PM_ (10) is 0.93%. The results show that the haze aerosol pollution is dominated by fine particles near the ground before the beginning of the dust, and the process is alleviated after the stratification and diffusion of the pollutants. The floating dust reached by exogenous transportation was distributed in the range of 800 m above, and the average depolarization ratio was 0.35, which was significantly higher than that in haze aerosol layer. In the early stage of sand dust, the boundary layer is raised to more than 900 m, and the floating dust is mixed with the local dust, which makes the near-ground pollution mainly increase with the increase of coarse particles, and the PM_ (10) hourly value increases to 920 渭 g / m 鈮，

本文編號：2523524