Berlin 2012 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 9: Poster session

UP 9.22: Poster

Mittwoch, 28. März 2012, 18:30–19:15, Poster F

Laboratory experiments on the nucleation and ice-growth of mesospheric dust particles — •Denis Duft, Markus Eritt, and Thomas Leisner — Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany

Meteoric Smoke Particles (MSP) are believed to be the basis for the formation of ice particles in the mesosphere. Under favorable conditions these particles can be observed from the ground as noctilucent clouds (NLC) and detected by radar as polar mesosphere summer echoes (PMSE). The occurence of these delicate ice particles can be used as a sensitive local probe for the otherwise elusive physical and thermodynamical conditions at the mesopause (80 – 90 km) and additionally to infer long term climatic trends in this height region. Despite of this importance, the microphysics of these mesospheric particles is not well understood. In this contribution we present laboratory experiments performed with the TRAPS apparatus on the nucleation and ice-growth of meteoric smoke particles under realistic mesospheric conditions. Charged composite-particles of SiO2, Fe2O3 und MgO (2 – 10 nm) are synthesized in a microwave reactor (100mbar), transferred directly into a vacuum chamber (10⁻⁷ mbar) using an optimized aerodynamic lens system and stored in a cooled linear ion trap (130 – 180 K). Nucleation and ice-growth on the trapped particles can be controlled by water vapor pressure adjustment and detected by Cavity Enhanced Absorption Spectroscopy (CEAS).