Yang Jun, Niu Zhong-qing, Shi Chun-e, Liu Duan-yang, Li Zi-hua
The Key Laboratory of Atmospheric Physics & Environment, Nanjing University of Information Science and Technology, Nanjing 210044, China.
Huan Jing Ke Xue. 2010 Jul;31(7):1425-31.
Intensive field observations of fog/haze events, including simultaneous measurements of aerosol particle and fog droplet size distributions, were conducted in Nanjing in November, 2007. Four weather conditions (fog, mist, wet haze and haze) were distinguished based on visibility and liquid water content firstly. Then, the microphysical characteristics of coarse and fine particles in each condition were investigated. The results showed the dominant sequence of the four weather conditions was haze<-->mist-->wet haze-->fog-->, wet haze-->mist<-->haze. The lasting time of pre-fog wet haze was longer than that of post-fog wet haze. The number, surface area and volume concentration of coarse particles with diameter larger than 2.0 micron in fog were much higher than those in the other three conditions, and the smallest concentrations were observed in haze. The size distributions of surface area and volume concentration exhibited multi-peak in fog droplets, while it showed single peak for coarse particles in haze, mist and wet haze. For the fine particles with diameter larger than 0.010 microm, the spectral shapes of surface area concentration are similar in fog (mist) and wet haze (haze) condition. The dominant size ranges of fine particle number concentration were in 0.04-0.13 microm and 0.02-0.14 microm for fog and wet haze, separately. The same dominant size ranges located in 0.02-0.06 microm for both mist and haze. During the transition processes from haze, mist and wet haze to fog, the concentration of smaller particles (less than 0.060-0.090 microm) reduced and vice versa for the corresponding larger particles. Temporal variation of aerosol number concentration correlated well with the root mean diameters negatively during the observation period. The number concentration of aerosol was the lowest and the mean diameter was the largest in fog periods.
2007年11月，在南京开展了雾/霾事件的密集实地观测，包括同步测量气溶胶粒子和雾滴的粒径分布。首先根据能见度和液态水含量区分出四种天气状况（雾、轻雾、湿霾和霾）。然后，研究了每种状况下粗、细颗粒物的微观物理特征。结果表明，四种天气状况的主导顺序为霾⇄轻雾⇄湿霾⇄雾，湿霾⇄轻雾⇄霾。雾前湿霾的持续时间比雾后湿霾的长。雾中直径大于2.0微米的粗颗粒物的数量、表面积和体积浓度远高于其他三种状况，霾中的浓度最低。雾滴的表面积和体积浓度的粒径分布呈现多峰，而霾、轻雾和湿霾中的粗颗粒物则呈现单峰。对于直径大于0.010微米的细颗粒物，雾（轻雾）和湿霾（霾）状况下的表面积浓度光谱形状相似。雾和湿霾中细颗粒物数量浓度的主要粒径范围分别在0.04 - 0.13微米和0.02 - 0.14微米。轻雾和霾的主要粒径范围均位于0.02 - 0.06微米。在从霾、轻雾和湿霾向雾的转变过程中，较小颗粒物（小于0.060 - 0.090微米）的浓度降低，相应较大颗粒物的浓度则相反。在观测期间，气溶胶数量浓度的时间变化与平均根直径呈负相关。雾期的气溶胶数量浓度最低，平均直径最大。
