The relevance of different heterogeneous ice formation processes for the precipitation budget

<p>Heterogeneous ice formation in mixed-phase precipitating clouds plays an important role in current weather and climate research. The complex interaction between aerosols, clouds and dynamics taking place within these clouds is still not understood. One major reason for that gap in knowledge is the fact that most of the relevant processes take place inside the complex turbulent environment inside of the cloud, making observations difficult. Also, the unknown impact of ice formation on cloud lifetime and precipitation evolution introduces large uncertainties into numeric weather prediction and climate projections.</p> <p>In the present study, we analyze datasets gathered at four different Cloudnet (Illingworth et al., 2007) sites in order to quantify and disentangle the impact of temperature and vertical air motions on precipitation formation. Basis for the investigation are combined measurements of lidar, cloud radar and ground-based disdrometer/rain sensor measurements processes with the Cloudnet algorithm. Fallstreak tracking methods are applied in order to connect rain events on the ground with their generating level/temperature at cloud top. We have evaluated combined remote sensing data gathered at different Cloudnet sites in order to contrast the relationship between cloud top temperature (CTT) and rain formation processes. The datasets at Leipzig (Germany), Limassol (Cyprus) and Punta Arenas (Chile) were collected with the Leipzig Aerosol and Cloud Remote Observations System (LACROS). The Barbados dataset was acquired with the Barbados Cloud Observatory (BCO) of Max-Planck Institute for Meteorology Hamburg.</p>