Aerosols, Clouds, and Atmospheric Chemistry

In April 2013 50 scientists from 6 different countries participated with 36 different hygrometers in a blind refereed intercomparison including traceable references. The intercomparison covered conditions simulating the UT/LS (186-233 K, 0.2-1300 ppmv) with static periods and dynamic changes including ice clouds. AquaVIT-2 will help reducing instrument uncertainties in order to better quantify the important role of atmospheric water vapor in weather and climate systems.

Together with the Teramobile Collaboration the interaction of fs- laser filaments with clouds was investigated. As detailed in a recent article in the Proceedings of the National Academy of Science of the United States http://dx.doi.org/10.1073/pnas.1222190110, the laser induced plasma channels did not influence ice nucleation in mixed phase clouds but had a remarkably strong effect on ice clouds at temperatures below the limit of homogeneous freezing. Read more: http://www.kit.edu/visit/pi_2013_13037.php

The effects of ultrafine particles, the smallest constituents of airborne particulate matter, on air quality, atmospheric processes, climate, and human health are by far not finally investigated to proven evidence. The 4th EFCA Ultrafine Particles Symposium will reflect the most recent scientific progress in the field and aims to contribute to the dialogue with policymakers in Europe.  The symposium takes place on May 16 - 17 in Brussels, Belgium. It is co-organized by KIT and chaired by the head of IMK-AAF, Prof. Thomas Leisner.

The joint NSF/DFG project ISOCLOUD investigates the water isotope fractionation by combining AIDA cloud simulation experiments with process modelling studies. In October 2012, the project partners achieved simulta- neous measurements of H2O, HDO, and H2(18)O both in the gas phase and the condensed phase. First results show the HDO fractionation to be in agreement with Rayleigh distillation assumptions. In March 2013, further AIDA experiments are planned to measure fractionation factors in cold cirrus clouds.

18.01.2013. Within the DFG-funded project ISI a team from IMK-AAF is currently investigating the microphysical properties of cloud droplet and ice particles at the high altitude research station Jungfraujoch in Switzerland. The aim of the study is to improve the current understanding of the formation processes and structure of mixed-phase clouds.