Dresden 2011 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 1: Poster Session

UP 1.13: Poster

Dienstag, 15. März 2011, 18:30–20:30, P2

Towards simulated cloud interaction of biological ice nuclei on regional scales — •Matthias Hummel, Corinna Hoose, and Heike Vogel — Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Karlsruhe, Germany

To initiate the heterogeneous freezing process of supercooled cloud droplets in atmospheric layers below 0 °C, ice nuclei (IN) are required. The properties of the variety of existing IN are decisive for their activation at particular ambient conditions (especially temperature and saturation). Experimental studies show that in addition to the well established mineral dust, aerosols of biological origin (e.g. pollen, bacteria) are the most active IN referring to temperature. Although the ice-active fraction of the biological IN is low, some (e.g. Pseudomonas syringae) start freezing even at -2 °C. Pollen in the pollination season can reach peak concentrations in the order of several per litre and many pollen species are ice-active. For better understanding and classifying their influence on clouds and precipitation, this work investigates the cloud interactions of pollen with the regional climate model COSMO-ART. By using this mesoscale model, very strong seasonal and regional variations are taken into account. In a first step simulated pollen concentration are compared with existing ones from global climate models.