IMCA

One interesting debate in the scientific community is the question if condensation freezing and immersion freezing are different mechanisms or not. To specifically study immersion freezing as it occurs in real world clouds we have developed the IMCA chamber, a vertical extension of the ZINC instrument. In this chamber, dry particles may activate as cloud droplets at warm temperatures and are subsequently cooled to the experimental temperature in ZINC where the freezing process is studied. Special care was taken in the design of this chamber that droplets do not evaporate during the cooling process. The following animation illustrates the fate of an aerosol particle during an IMCA/ZINC freezing experiment. The frozen fraction is measured at the bottom of the chamber with our IODE depolarization detector.