Research

Research interests:

- cloud microphysics
- nucleation of solid phases in atmospheric aerosols
- heterogeneous nucleation
- aerosol physics
- aerosol measurements and instrumentation
- aerosol composition analysis

The International Workshop on Comparing Ice Nucleation Measuring Systems (ICIS 2007):

Together with my colleagues Ottmar Möhler and Paul DeMott I am co-organizing the ICIS Workshop 2007 to be held in Karlsruhe, Germany, 10-28 September. The objective of this workshop is to compare all currently existing instruments which measure ice nucleation at the AIDA facility with a common aerosol generation system.

The Arctic Summer Cloud-Ocean Study 2008 (ASCOS):

An international project, coordinated by Stockholm University, to investigate the interactions between the Arctic icecap, the overlying boundary layer, and the ubiquitous low-level stratiform cloud. A 2-month field campaign will be conducted from the Swedish Icebreaker Oden during the summer of 2008. We will be on board with our new portable ice nucleation chamber (PINC) and the aerosol mass spectrometer ATOFMS.

Research projects:

The focus of the research in my group is to study various modes of ice nucleation in the atmosphere with different experimental techniques, such as the ZINC and PINC instruments (see below). In addition some projects are related to detecting and imaging ice crystals with optical techniques.

Further information coming soon....

The Zurich Ice Nucleation Chamber (ZINC):

The Zurich Ice Nucleation Chamber is a new instrument to measure heterogeneous ice nucleation on airborne particles. The concept is derived from the Continuous Flow Diffusion Chamber (CFDC) developed at Colorado State University. In contrast it has a parallel plate geometry and is almost entirely made of aluminum. It will later be equipped with the depolarisation detector IODE (see below) to detect ice crystals and differentiate them from water droplets in situ.

The Portable Ice Nucleation Chamber (PINC):

The PINC instrument is a further development of the ZINC chamber. It is especially constructed for field studies and in particular research aircraft. This instrument is currently still under construction.

The  Ice Optical Detector (IODE):

One PhD project within my group aims at constructing a depolarisatioin detector for the ZINC and PINC instrument. This detector measures backscattering of  individual single particles in 175°. The light source is a polarized laser at  407 nm. The depolarization of individual particles will be detected by simultaneous measurment of the backscattered signal in two perpendicular channels.