Aarhus University Seal / Aarhus Universitets segl

Seminar on ice nucleation

Thomas B Kristensen gives a seminar at the Department of Chemistry

2016.03.01 | Susanna Pakkasmaa

Date Thu 03 Mar
Time 10:15 11:15
Location Department of Chemistry, building 1513, room 435

Seminar on ice nucleation and results from the cloud chamber in CERN - Thomas B Kristensen

Secondary organic aerosol (SOA) particles play significant roles in the atmosphere with respect to climate and health. Recently it has been reported that SOA particles can be present in a semi-solid, amorphous state in the atmosphere. The phase state of SOA particles depends on external parameters such as temperature and relative humidity, as well as internal parameters.

Model studies and studies of proxies of viscous SOA indicate that viscous SOA particles may facilitate freezing in the atmosphere. However, ice nucleation studies of SOA particles comprised of atmospherically relevant species are scarce. In the present study we investigated the phase state of SOA particles produced from ozonolysis of alpha-pinene in the CLOUD chamber at CERN. In addition, we report the ice nucleation ability of the viscous SOA particles investigated externally with the continuous flow diffusion chamber SPectrometer for Ice nucleation (SPIN). Our results indicate that viscous SOA particles are likely to be present at higher altitudes, and that they may influence cirrus cloud properties in the atmosphere at temperatures below approximately -35°C.

Thomas B Kristensen works at the Leibniz Institute for Tropospheric Research. His research interests are

  • Ice nucleation
  • Cloud microphysics and aerosol cloud interactions
  • Organic aerosol and humic-like substances
  • Marine aerosol