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Karlsruhe Institute of Technology (KIT) – The Research University in the Helmholtz Association creates and imparts knowledge for the society and the environment. It is our goal to make significant contributions to mastering the global challenges of mankind in the fields of energy, mobility, and information. For this, about 10,000 employees of KIT cooperate in a broad range of disciplines in research, academic education, and innovation.

The Institute of Meteorology and Climate Research Atmospheric Aerosol Research (IMKAAF) is offering as of October 1st, 2025 and limited for 3 years a

PhD student position (f/m/d) within the DFG-funded research project “Secondary ice production mechanisms: rime splintering and droplet shattering on freezing- (75 % part-time)

Reliable modeling of cloud processes for weather predictions and climate change projections requires a sound understanding of the ice formation in mixed-phase clouds. Typically, ice particles form via heterogeneous freezing of supercooled cloud droplets containing ice nucleating particles (INPs). Ice crystal concentrations measured inside the clouds are often found to exceed the concentration of INPs by many orders of magnitude. To explain this discrepancy, the Secondary Ice Production (SIP) mechanisms, i.e., processes producing multiple ice particles upon freezing of a single cloud droplet or by fragmentation of existing ice particles, must be studied.

In a DFG-funded collaborative project between the Institute of Meteorology and Climate Research (IMK) and the Leibniz-Institute for Tropospheric Research (TROPOS) in Leipzig, we are investigating two potential SIP mechanisms: production of secondary ice particles caused by (A) droplet-ice collisions (rime-splintering) and (B) splintering of freezing droplets (see Figure 1). These two SIP mechanisms have been suggested to be of particular relevance in the mixed-phase clouds.

Job description

Our Institute IMKAAF seeks a highly motivated PhD student (f/m/d) to work on the experimental investigation of droplets splintering on freezing.

The successful candidate will:

• conduct experiments with the new experimental set-up, the Ice Droplet splintEring and Fragmentation eXperiment (IDEFIX);
• participate in experiments on identification of the physical mechanisms of rime-splintering SIP events together with the leading scientists at TROPOS;
• contribute to parameterization development for both SIP mechanisms;
• take part in the measuring campaign investigating SIP in mix-phase clouds.
• The parameterizations developed as a part of this PhD project will be applied for representation of SIP mechanisms in cloud microphysics resolving models.

Personal qualification

You have:

• A masters degree in physics, environmental physics, geophysics or meteorology
• Experimental skills and motivation to work in the lab
• Very good knowledge of parallel programming concepts and technologies
• Good communication skills, fluent English language in writing and speaking

Become a member of staff of the only German University of Excellence that conducts large-scale research on the national level. Work under excellent working conditions in an interna-tional environment and be active in research and academic education for our future. Benefit from specific training when starting your job and from a wide range of further qualification offers. Use our flexible working time models (flexitime, work from home), our sports and leisure offers, as well as our child and holiday care services. We also pay a share of EUR 25/month in the Job Ticket Baden-Württemberg. Enjoy a large variety of dishes, snacks, and beverages at our canteens.

We prefer to balance the number of employees (f/m/d). Therefore we kindly ask female applicants to apply for this job.

Recognized severely disabled persons will be preferred if they are equally qualified.

Please apply until August 31, 2025 by using the vacancy number 299/2025 to Ms König, Karlsruhe Institute of Technology (KIT), Human Resources, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany. For further information, please contact Dr. Alexei Kiselev, phone: +49 721 608-26662, E-Mail: alexei.kiselev@kit.edu or visit the homepage of IMKAAF: .

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