Design of a Dual-Tank Mixed Cloud Chamber and Quantitative Seeding Experiments for Warm and Cold Clouds

Cloud chamber experiments provide a controlled environment for investigating the microphysical processes that govern cloud formation, as well as elucidating the physical mechanisms underlying artificial weather modification. The Dual-Tank Mixed Cloud Chamber (2.7 m³ + 9 m³) allows precise control of temperature (−40-40°C), pressure (30-1110 hPa), and humidity. It is equipped with a comprehensive suite of instruments capable of monitoring the entire particle size distribution and activation, from aerosols to fog droplets. Quantitative seeding experiments for warm cloud (12°C)and cold clouds (-4°C) were performed to systematically examine their formation characteristics and microphysical responses to different seeding agents. In the warm-cloud experiments, the introduction of 10 g of a hygroscopic catalyst induced rapid nucleation of small droplets (3-10 μm), while simultaneously increase the development of larger droplets (≥ 20 μm) through enhanced hygroscopic growth. Under the -4°C condition in the cold-cloud experiments, the introduction of 0.5 g of AgI increased the submicron aerosol number concentration to 2 × 10⁴ cm⁻³, promoting rapid ice crystal formation that subsequently triggered the freezing and precipitation of liquid droplets.