Studies of Ice Nucleation in the Leipzig Aerosol-Cloud Interaction Simulator Leibniz-Institute for Tropospheric Research

Emphasis area: Atmospheric Physics

PI: Raymond Shaw

Sponsor/Agency: Leibniz-Institute for Tropospheric Research

Total Funding:

Period funded:

Details:

This project involves research on the topic of ice nucleation, to be carried out at the Leibniz-Institute for Tropospheric Research (IfT) in Leipzig, Germany through August 2008. The research will utilize the new world-class cloud physics facility at IfT, the Leipzig Aerosol-Cloud Interaction Simulator (LACIS). Existing grants from the German National Science Foundation (DFG) are supporting the use of this facility for research closely related to the plan outlined here, and the proposed work naturally benefits greatly from this existing level of support and commitment. The research will be carried out in collaboration with IfT colleagues Prof. Dr. Jost Heintzenberg, Dr. Alexei Kiselev, Dr. Frank Stratmann, and Dr. Heike Wex.

The research projects include:

1. Development of LACIS configuration suitable for low-temperature experiments, with water and ice supersaturations.

2. Evaluation of the suitability of LACIS for ice nucleation studies via measurements on activation, growth, and evaporation of supercooled droplets. Resulting data will be quantitatively compared to an existing computational model of the thermodynamics and particle growth rates in LACIS flow tube. This will include an analysis of the mass accommodation and thermal accommodation coefficients for water for low temperatures, and for a range of vapor fluxes (both evaporation and freezing).

3. Initial exploratory measurements of ice nucleation by immersion and evaporation freezing, with the objective of making initial evaluation of the relative roles of these two competing processes. This work will lay the groundwork for future ice nucleation studies to evaluate specific mechanisms for evaporation freezing and surface crystallization, for example, by choosing ice nuclei with a range of water-interfacial properties.