Ice nucelating particles (INP) are a subset of aerosols in the atmosphere that can form ice crystals at warmer temperatures than when droplets freeze homogeneously. They are typically low in abundance but have important implications for clouds and for weather and climate. The presence of ice crystals alters the optical properties and microphysical processes of clouds, affecting for example the probability of precipitation and cloud lifetime.
Different materials and aerosol properties affect whether an aerosol acts as an INP and at which temperature. Given the importance of INP in the climate system, we want to improve our understanding of INP sources by INP measurements. However, measuring INP is complex and requires careful development of the method.
At EERL, we set up an INP freezing assay in the laboratory and are in the process of characterizing the instrument and identifying a good blank, so that pure water only freezes at -25 to -30°C. The aim of this semester project is to help perform characterizing measurements and determine the potential INP baseline signal of various commonly used materials for INP sampling and handling, e.g. filter substrates, sampling tubes, bacteria growth plates etc. This semester project therefore is mainly based on laboratory work.
Contact: Nora Bergner ([email protected])