气溶胶充当云凝结核 (CCN) 参与云的微物理过程是气溶胶间接效应的重要研究内容之一。四川盆地位于青藏高原东侧，复杂的地形和气象条件导致气溶胶独特的理化特征为该地区气溶胶与CCN的关系增添了较大的不确定性。本项目拟在四川盆地典型城市针对气溶胶吸湿特性和活化特性开展地基综合观测，利用统计方法系统分析该地区气溶胶理化性质和活化特性的变化特征以及相互之间的关系，确定不同水汽条件下气溶胶的活化率曲线和临界活化粒径。在此基础上，通过闭合试验的方法，深入研究影响该地区气溶胶吸湿特性和活化特性的物理化学因子，进而确定和完善适用于四川盆地的气溶胶–CCN数浓度的参数化关系，以期为数值模式中针对该地区气溶胶与云相互作用的参数化方案的改进提供科学基础。

Aerosols, act as cloud condensation nuclei (CCN), participating in cloud microphysical processes is one of the important research contents of aerosol indirect effect. The complex topography and meteorological conditions in the Sichuan Basin, which located to the east of Qinghai-Tibet Plateau, lead to the unique physical and chemical characteristics of aerosols, contributing to large uncertainty in the relationship between aerosols and CCN. Thus, this project intends to carry out comprehensive ground-based observations focusing on aerosol hygroscopicity and activation properties in a typical city in the Sichuan Basin. The variation characteristics of physicochemical and activation properties of aerosols and their relationships will be systematically analyzed by statistical methods in this region. The size-resolved activation curves and the critical diameters under different water vapor conditions will be determined. On this basis, the physical and chemical factors that affect aerosol hygroscopicity and activation properties will be deeply investigated in this area, and the appropriate parameterized relationship between aerosol and CCN number concentration will be determined and perfected to be applied in the Sichuan Basin by using the closure studies. This will provide a scientific basis for the numerical model to improve the parameterization schemes for aerosol–cloud interactions in this region.