Heidelberg 2015 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 4: Postersession Atmosphäre

UP 4.21: Poster

Mittwoch, 25. März 2015, 10:45–19:45, G/Foyer

A novel experimental setup to study heterogeneous nucleation and growth rates on meteor smoke particle analogues — •Mario Nachbar¹, Denis Duft², and Thomas Leisner^{1, 2} — ¹University of Heidelberg, IUP, Germany — ²Karlsruhe Institute of Technology - IMK-AAF, Germany

Noctilucent clouds (NLC) have been detected in the polar summer mesopause region of Earth at heights of 80-90 km. These clouds are believed to be caused by heterogeneous nucleation of H2O on meteoric smoke particles (MSP). Surprisingly, similar clouds have been detected in the mesosphere of Mars as well. In contrast to NLCs on Earth, they consist of CO2 particles and occur at subtropical latitudes mostly during post aphelion season. Scientist dealing with the formation of NLCs struggle with large uncertainties in describing the nucleation processes taking place due to a lack of experimental data at the extreme mesospheric conditions which states the need of laboratory measurements. We recently designed a new linear ion trap which allows us to trap nanoscale particles under controlled temperature as well as H2O and CO2 concentration. We produce charged nanometer sized MSP analogues in a microwave resonator and transfer them to the ion trap held under typical mesospheric conditions. Heterogeneous ice nucleation and growth processes then can be examined by analyzing the mass distribution of the particles with a time-of-flight mass spectrometer as function of the residence time under supersaturated conditions. In this paper, the experimental setup and data analysis is exemplified with experiments on CO2 nucleation in the Martian mesosphere.