Atmospheric Measurement Techniques Discussions www.atmos-meas-tech-discuss.net 1867-8610 2 1 2009 10.5194/amtd-2-153-2009 http://www.atmos-meas-tech-discuss.net/2/153/2009/ http://www.atmos-meas-tech-discuss.net/2/153/2009/amtd-2-153-2009.html http://www.atmos-meas-tech-discuss.net/2/153/2009/amtd-2-153-2009.pdf 153 179 2009-01-30 A new thermal gradient ice nucleation diffusion chamber instrument: design, development and first results using Saharan mineral dust G. Kulkarni S. Dobbie J. McQuaid School of Earth and Environment, University of Leeds, Leeds, UK now at: Atmospheric Science and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA A new Thermal Gradient ice nucleation Diffusion Chamber (TGDC) capable of investigating ice nucleation efficiency of atmospherically important aerosols, termed Ice Nuclei (IN), has been designed, constructed and validated. The TGDC can produce a range of supersaturations with respect to ice (SSi) over the temperature range of −10 to −34°C for sufficiently long time needed to observe the ice nucleation by the aerosol particles. The novel aspect of this new TGDC is that the chamber is run in static mode with aerosol particles supported on a Teflon substrate, which can be raised and lowered in a controlled way through the SSi profile within the chamber, and nucleation events are directly observed using digital photography. The TGDC consists of two ice coated plates to which a thermal gradient is applied to produce the range of SSi. The design of the TGDC gives the ability to understand time-related ice nucleation event information and to perform experiments at different temperatures and SSi conditions for different IN without changing the thermal gradient within the TGDC. 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