Aerosol characteristics including fumigation effect under weak precipitation over the southeastern coast of China

Aerosol size distribution, total number concentration, scattering coefficient and absorption coefficient were measured in Quanzhou on the southeastern coast of China, from December 13, 2010 to January 16, 2011. Five light-rain events were analyzed for statistical study and one typical light-rain process was chosen as the case study for analysis in detail. The study focuses on the influence of weak precipitation on aerosol light-scattering and absorption properties as well as the size distribution. Similar size distributions were observed between clear-day regime and light-rain regime. The scavenging coefficient in the scavenging gap was about 10−4 s−1 with the mean precipitation intensity of 0.5 mm/h, which were significantly larger than those of model estimations but close to those from other field measurements. Fumigation effect was also observed in the light-rain day due to the downward flow from the clouds at the beginning of precipitation in this measurement.

► Aerosol characteristics in coastal region of China were obtained. ► Fumigation effect was also observed in the rainy day. ► Aerosol natural scavenging coefficient in the scavenging gap was estimated. ► The curve of scavenging coefficients was different from theoretical results.