Partner 22 - IfT (Germany)
Leibniz Institute for Tropospheric Research (IfT)

Expertise and experience of the organization
The IfTis engaged in investigations concerning the physics, chemistry, and modelling of the troposphere. Focus of the scientific research are the physical and chemical properties of aerosol particles and their interactions with clouds and radiation; transformations of trace substances in the vicinity of their sources, and exchange of energy and matter at internal and external boundaries of the troposphere. In all three foci research at IfT is concentrating increasingly on condensed trace substances in the form of aerosol particles and cloud elements. Besides their physical and chemical characterization, processes affecting the exchange between atmospheric reservoirs and the atmospheric effects of the condensed phase are being investigated by the institute. The institute employs approximately 50 scientists in 3 departments. IFT participates in the following current EC projects: EARLINET, AEROTOOLS, ACCENT, UFIPOLNET, EUSAAR, EUCAARI.
Role and contribution
IfT is involved in the characterization of the aerosol emission study in Paris, France. A full determination of physical aerosol properties at the ground (in-situ measurements), the vertical aerosol profile (Raman lidar), and the chemical characterization (mass spectroscopy) will be performed in the centre of Paris.

Principal personnel involved
Prof Dr. Alfred Wiedensohler - is the deputy head of the physics section at IFT and is scientifically involved in the ‘Tropospheric Aerosol’ group. The ‘Tropospheric Aerosol’ group consists of several scientists, doctoral students, undergraduate students, and two technicians engaged in atmospheric science. The main subjects are dynamics of ultrafine and fine aerosols, optical and hygroscopic properties, and their climatology. The research methods are both experimental and theoretical. He was or is involved in several International field projects such as EUROTRAC-GCE, International Arctic Ocean Expedition 1991, ACE-1 and ACE-2, INDOEX, and ACE-Asia.  He is head of the World Calibration Centre for Physical Aerosol Properties within the WMO-GAW program and member of the Scientific Advisory group within WMO-GAW. His expertise is in aerosol physics, aerosol instrumentation, and physical properties of atmospheric aerosols. He is author and co-author of more than 130 peer-reviewed publications.

Selected relevant publications
Massling, A., Stock, M., Wiedensohler, A. (2005): Diurnal, Weekly, and Seasonal Variation of Hygroscopic Properties of Submicrometer Urban Aerosol Particles. Atmos. Environ., 39, 3911-3922.
Wehner, B., Petäjä, T., Boy, M., Engler, C., Birmili, W., Tuch, T., Wiedensohler, A., Kulmala, M. (2005): The contribution of sulfuric acid and non-volatile polymer-like organics on the growth of freshly formed atmospheric aerosols. Geophs. Res. Let., 32, L17810.
Wehner, B., Wiedensohler, A., T.M., T., Wu, Z. J., Hu, M., Slanina, J., Kiang, C. S. (2004). Variability of the aerosol number size distribution in Beijing, China: new particle formation, dust storms, and high continental background. Geophs. Res. Let., 31, L22108.
Ansmann, A., D. Müller, (2005): Lidar and atmospheric aerosol particles, in Lidar. Range-Resolved Optical Remote Sensing of the Atmosphere, Ed. C. Weitkamp, Springer (Singapore), 105-141.
Müller, D., U. Wandinger, A. Ansmann, (1999): Microphysical particle parameters from extinction and backscatter lidar data by inversion with regularization: Theory, Appl. Opt., 38, 2346-2357..
Veselovskii, I., A. Kolgotin, V. Griaznov, D. Müller, K. Franke, D. N. Whiteman, (2004): Inversion of multiwavelength Raman lidar data for retrieval of bimodal aerosol size distribution, Appl. Opt., 43, 1180-1195.

FP7 EC MEGAPOLI, 2008-2011