Aerosols, Clouds, and Atmospheric Chemistry

Ice particles in Arctic boundary layer clouds are in the focal point of the German scientific expedition VERDI. The main goal of VERDI is to understand the role of these clouds in the strong warming observed in the Artic over the last decades. The clouds are probed by a novel set of instruments onboard the Polar 5 research aircraft, which is operated by the Alfred Wegener Institute (AWI). VERDI is based in Inuvik, NWT, Canada, for research flights over the Beaufort Sea. 

The formation of the ice phase in tropospheric clouds has multiple impacts on the hydrological cycle and the climate system. Many aspects of ice nucleation induced by a minor subgroup of the atmospheric aerosol system, so-called ice nuclei, remain unclear and will be addressed by the Research Unit INUIT, which was recently established by the German Research Foundation (DFG). In two projects, the IMK-AAF will contribute comprehensive laboratory and modeling studies on ice nucleation.

IMK-AAF disclosed its pioneering Particle Habit Imaging and Polar Scattering (PHIPS) probe in the Journal of Atmospheric Measurement Techniques (October 12, 2011). Developed for the German research aircraft HALO, it simultaneously measures the 3-D morpho- logy and corresponding optical and microphysical parameters of individual cloud particles. The paper outlines the concept and design of PHIPS and dis- cusses preliminary results of two ice cloud campaigns con- ducted in the AIDA chamber.

New sampling inlets and continuous aerosol measurements have been installed at the environmental research station Schneefernerhaus (UFS) in summer 2011. The IMK-AAF investigated aerosol - cloud interactions in warm clouds with focus on bioaerosol, soot, water budget in cooperation with the IMK-IFU on three plattforms (UFS, Zugspitze, and ultralight research aircraft) during a 2-week summer campaign.