Impact of aerosols on the physical parameters of cloud and precipitation processes in the eastern slope region of the Qinghai-Xizang Plateau

Aerosols have a complex and uncertain impact on clouds and precipitation. The uneven spatial-temporal distribution of aerosol concentrations caused by the complex mountain and basin terrain of the eastern slope of the Qinghai-Xizang Plateau has significant and differential effects on various physical parameters during the cloud and precipitation processes. This study utilizes high-resolution (0.25°×0.25°) aerosol optical depth (AOD) data and CM SAF's CLARA-A3 cloud products (including liquid water path and ice water path) to analyze aerosol-cloud interactions in the eastern Qinghai-Xizang Plateau. Additionally, raindrop spectroscopic observations (OTT Parsivel2) from Emei Mountain Station are used to further quantify the impact of aerosols on precipitation microphysics under different rainfall intensities. Results show that Seasonal AOD variations (0.22±0.03 in spring −0.13±0.02 in winter) drive differential cloud responses, with strong correlations (Pearson correlation coefficient: r =0.42±0.08) for liquid water path but negative correlation for ice particle size (Pearson correlation coefficient: r =−0.22). Raindrop spectrum shifts show aerosol-induced bifurcation: low-AOD increase concentrations of small droplets (<1 mm) by 18%−35% in stratiform clouds while reducing large droplets (>3 mm) by 22%±5%. Rainfall intensity modulates effects—under heavy rain (rain intensity: R ≥2 mm/h), aerosols suppress large-drop formation by 40% compared to light rain. These results establish quantitative thresholds for aerosol-cloud interactions in high-altitude regions.