城市大气中超细气溶胶老化增长潜势及其对云凝结核数浓度影响的研究

模式中云凝结核（CCN）数浓度的准确模拟对研究气溶胶-云-降水相互作用具有十分重要的意义，现今天气和气候模式中高污染城市地区CCN数浓度被明显低估。本项目将基于一个典型城市站点气溶胶物理、化学特性的外场观测数据，（1）利用超细气溶胶增长概率（PUG）模式，量化城市地区超细气溶胶的源和汇，研究不同来源超细气溶胶老化增长成为CCN尺度粒子的潜势；（2）结合有机物吸湿活化特性的分析，进一步研究超细气溶胶演变过程中气溶胶活化特性的改变，最后建立适用于城市地区的CCN数浓度估算方案。项目预期成果将有助于改进模式，增强受人为污染严重地区CCN数浓度模拟的准确性。

It is of great significance to accurately simulate the number concentration of cloud condensation nuclei (CCN) in the model for studying aerosol-cloud-rainfall interactions. However, the CCN number concentration in highly polluted urban areas is significantly underestimated in current weather and climate models. This project will be based on the field observations of aerosol physical and chemical properties at one typical city site, (1) to quantify the sources and sinks of ultrafine aerosols in urban areas using the Probability of Ultrafine particle Growth (PUG) model, and study on the aging growth potential of ultrafine aerosols from different sources to become CCN-scale particles; (2) to further investigate the change of aerosol activity during the evolution process of ultrafine aerosols combining with the analysis of the hygroscopicity and activation properties of organic compounds. Finally, CCN number concentration estimation schemes adapted to urban areas will be established. This project is supposed to improve the model and enhance the accuracy of simulated CCN number concentration in areas with severe anthropogenic pollution.