HINC
Based on the design of the University of Toronto Continuous Flow Diffusion Chamber (UT-CFDC)1 the Horizontal Ice Nucleation Chamber HINC is particularly designed to study the ability of ambient aerosols to activate as ice nuclei (IN). Especially in the context of a changing climate, the influence of ice and mixed-phase clouds on the Earth’s radiation budget remains one of the largest uncertainties2. Therefore not only a better understanding of general ice crystal formation mechanisms is needed, but it is also highly important to quantify the ice nucleating ability of ambient aerosols. In this context, conducting field measurements is the only way forward.
HINC is one of the two portable ice nucleation chambers in our group and is operated at the external page High Alpine Research Station Jungfraujoch on a regular basis. The main research question in this study is to get an insight in the annual IN cycle and to refer to differences in IN number concentrations when sampling in convectively lifted boundary layer air, compared to the usual free tropospheric conditions that prevail at the observational site2.
Contact: Fabian Mahrt, Cyril Brunner
Working principle:
HINC consists of two horizontal plates which can be cooled to temperatures relevant for ice and mixed-phase clouds. As the plates are covered with wet filter papers, a supersaturation with respect to water and ice is established through a temperature difference of the upper and lower plates. Two freezing modes can be investigated in HINC: Deposition freezing with RHice > 100% but RHwater < 100% and condensation freezing with both RHice and RHwater > 100%.
References:
Mahrt, F., et al. (2018), 'Ice nucleation abilities of soot particles determined with the Horizontal Ice Nucleation Chamber', Atmos. Chem. Phys., 2018, 1-41. (external page https://doi.org/10.5194/acp-2018-557)
Lacher, L., et al. (2017), 'The Horizontal Ice Nucleation Chamber (HINC): INP measurements at conditions relevant for mixed-phase clouds at the High Altitude Research Station Jungfraujoch', Atmospheric Chemistry and Physics, 17 (24), 15199-224. (external page https://doi.org/10.5194/acp-17-15199-2017)