PhD Position on Secondary Ice Production with focus on Ice Fragmentation during Graupel Formation (m/f/div)

PhD Position on Secondary Ice Production with focus on Ice Fragmentation during Graupel Formation (m/f/div) Leibniz Institute for Tropospheric Research (TROPOS), Leipzig The Leibniz Institute for Tropospheric Research (TROPOS) is an internationally renowned institute in the field of aerosol and cloud research. The Atmospheric Microphysics Department (AMP) researches atmospheric aerosol particles, their interactions with clouds and turbulence, and cloud microphysics. The focus is on both process-based studies and long-term observations, with which we contribute to the understanding of climate change and its consequences. The climate effect and the ability of mixed-phase clouds to form precipitation is strongly dependent on the presence of ice crystals. Observations show that secondary ice formation processes play an important role in mixed-phase clouds. A central secondary ice formation process is ice fragmentation during the formation of graupel (rime-splintering also known as the Hallett-Mossop process). In the previous DFG project – in contrast to earlier studies – no efficient secondary ice formation was observed under near-atmospheric conditions within the parameter range investigated. This fundamentally questions the process of rime-splintering. Within the DFG follow-up project, we will extend the parameter range, improve the detection limit of small ice particles and address open questions concerning the role of small droplets, ice surface roughness and influences of rimer rotation, humidity and pressure on the secondary ice formation process. To this end, the existing IDEFIX (Ice Droplet splintEring on FreezIng eXperiment) experimental setup will be further developed and laboratory experiments will be carried out, analyzed and interpreted. The aim of this research project is to gain a better understanding of the microphysical processes, quantify the number of secondary ice particles and thus will contribute to improving weather and climate projections. The project is being carried out in close collaboration with Dr. Alexei Kiselev and his research team at the Karlsruhe Institute of Technology. The Department of Atmospheric Microphysics is looking for a committed doctoral student to realize this project. You can expect an exciting research activity at a non-university, internationally networked institute with a dynamic and interdisciplinary working environment. Your tasks: Carrying out, analyzing and interpreting laboratory experiments on the above described topic. Support in the further development of the IDEFIX experimental setup. Presentation of the results at international conferences. Preparation of a cumulative dissertation with two to three publications of the scientific results in renowned, peer-reviewed journals is aimed for. Co-operation with external project partners. Your qualifications: Successfully completed Master\’s degree in the field of meteorology, or related disciplines such as physics, engineering or geosciences. High level of motivation and willingness to research this topic. Interest in laboratory work and basic technical understanding. Fluent written and spoken English. Programming skills in e.g. Python, R, Matlab and Java. Experience in image processing, aerosol or cloud microphysical measurement technology and automatization is desirable. Driving License (German Class B or equivalent) desirable. The position will be filled by 1 October 2025 at the earliest. We offer an exciting position with varied activities in an interdisciplinary working environment and a variety of measures to reconcile work and family life as well as flexible working hours and daycare places. The employment is limited to 36 months (65% TV-L 13) including the attractive social benefits of the public service. In order to increase the proportion of female employees in scientific and science-related positions, we hereby expressly invite female applicants to apply. Severely disabled persons (according to the Ninth Book of the German Social Code) will be given preference if they have the same aptitude, skills and professional qualifications. If you are interested, please send your complete and informative application documents (including references and a letter of motivation) by 30. August 2025 exclusively by e-mail in one coherent PDF document to: application(at)tropos.de; subject: IDEFIX II (AMP) If you have any questions about this vacancy, please contact: Dr. Susan Hartmann, susan.hartmann(at)tropos.de, +49(0)341-2717-7489 By sending the application documents by e-mail, the applicant agrees to the storage/processing of personal data in accordance with Art. 13 GDPR for the purpose of selection for this job advertisement. Attention is hereby drawn to the risks involved in sending documents electronically. Further information on TROPOS can be found on the homepage: www.tropos.de and in the following publication: J. S. Seidel, A. A. Kiselev, A. Keinert, F. Stratmann, T. Leisner, S. Hartmann, Secondary ice production – no evidence of efficient rime-splintering mechanism. Atmos. Chem. Phys. 24 , 5247-5263 (2024). doi:10.5194/acp-24-5247-2024.