The Aerosol–Cloud Interactions team, led by Dr. Silvia Henning, investigates how aerosol particles influence the formation, development, and properties of clouds. A particular focus is on cloud condensation nuclei (CCN) and ice-nucleating particles (INP).
CCN enable the formation of cloud droplets by binding water vapor already at low supersaturation. Their number, chemical composition, and size determine how many droplets form and how large they become. These factors are crucial for the radiative properties of clouds and influence whether and when precipitation occurs.
INP promote the freezing of cloud droplets by lowering the energy barrier for ice formation. Depending on the nature of the particles, this process can begin at temperatures just below 0 °C or only occur at much lower temperatures. In the laboratory, we investigate which aerosol particles trigger freezing, how ice particles continue to grow, and which mechanisms lead to a multiplication of ice particles.
In addition to laboratory studies, we conduct worldwide measurements to determine the concentration and origin of CCN and INP. Furthermore, we collect ice particles from real clouds in order to analyze their composition and draw conclusions about their formation. Our research contributes to a better understanding of cloud processes and to a more precise description of their role in the climate system.
HALO South explores atmospheric regions far removed from established observation networks using the research aircraft HALO. The mission enables new insights into the composition, dynamics, and radiative effects of the atmosphere over the Southern Hemisphere.