Aerosol-cloud interactions in liquid-phase clouds under different meteorological and aerosol backgrounds

Abstract. We conduct a comparative analysis of aerosol-cloud responses in liquid-phase clouds under different aerosol and meteorological conditions based on simulations using the WRF-Chem-SBM model to improve our understanding of aerosol-cloud interactions. This study reveals that in relatively unstable but dry atmosphere, aerosols uplift cloud top height but have no significant impact on cloud thickness, while also suppressing precipitation in clean conditions (sea salt aerosol only). In relatively stable but humid atmosphere, aerosols significantly increase both cloud top height and cloud thickness. Although aerosols also suppress precipitation in clean conditions, they promote the occurrence of relatively intense precipitation by facilitating the development of deep clouds. Aerosols have both enhancing and weakening effects on cloud liquid water path (CLWP). The weakening occurs mainly through two mechanisms: 1) by increasing N_d in thin clouds within a dry atmosphere, leading to smaller droplet sizes, which enhances evaporation within clouds and thus reduces CLWP. 2) By lifting cloud top height, facilitating the transition of liquid-phase clouds into mixed-phase or ice-phase clouds. The enhancing effect becomes more pronounced in environments with a relatively high column-averaged relative humidity, and is also modulated by atmospheric stability: 1) under low lower tropospheric stability (LTS), aerosols cause a relatively brief, explosive increase in CLWP. 2) Under high LTS, aerosols lead to relatively persistent increase in CLWP. For the liquid-phase clouds in the study, aerosols affect cloud development but have no significant impact on cloud lifetime, and precipitation affects the short-term variation of N_d but does not change its overall trend.