The Atmospheric Physics group of Prof. Ulrike Lohmann at the Institute for Atmospheric and Climate Science (IAC) at ETH Zurich invites applications for a 3-year to 3.5-year PhD position in Experimental Cloud Physics on Lagrangian cloud measurements with a holographic imager. Our research focuses on the role of clouds in the climate system.  Our goal is to gain a better understanding of the cloud microphysical processes leading to precipitation in clouds involving ice.

Field measurements in atmospheric science often measure the state of a cloud but not the rates of cloud processes, which are crucial for refining parameterization in weather and climate models. To overcome this limitation, orographic wave clouds can serve as a natural laboratory for investigating microphysical cloud processes. Orographic wave clouds (lenticularis clouds) are clouds that form when air masses flow across hills and mountains in a statically stable atmosphere. The rising motion causes vapour to condense into cloud droplets, which may freeze if temperatures are sufficiently low. Conversely, during the downward motion, the cloud dissipates as cloud droplets evaporate and/or ice crystals sublimate. The goal of this project is to develop a helium-filled balloon with zero buoyancy which follows the airflow over the mountain. Employing this balloon drifter with a holographic imager to observe changes in droplet and ice crystal size distributions, allows for Lagrangian measurements along atmospheric trajectories. By deriving cloud process rates due to diffusion, riming and aggregation from these observations, we aim to enhance our knowledge of cloud microphysics and to improve parameterizations in weather and climate models.

Your tasks will be:

• To develop a light-weighted holographic imager and a balloon drifter system.
• To perform measurements with a holographic imager on a balloon acting as Lagrangian drifter across different mountain ridges in Switzerland.
• To investigate how the height and shape of the mountain ridge influence cloud formation.
• To infer the ice crystal growth rate from changes in the droplet and ice particle size distribution as a function of cloud temperature and liquid water content.

In general, doctoral researchers at ETH Zurich have a full-time employment. A part-time employment may only be considered in exceptional cases (e.g. child- or familycare, other projects or employment).

Your profile should be:

• MSc (or equivalent) in atmospheric/environmental science, physics, engineering, or related field.
• Sound knowledge of the English language, both orally and written is expected.
• Experience in designing optical and electronic instruments, in particular printed circuit board (PCB), is an advantage.
• Motivation to work in the field in rough condition (night, cold temperatures).
• Good communication and time management skills, as well as willingness to participate in a collaborative and supportive research environment.

Applications from members of underrepresented groups in academia are specifically encouraged.

ETH Zurich is a family-friendly employer with excellent working conditions. You can look forward to an exciting working environment, cultural diversity and attractive offers and benefits.

In line with our values, ETH Zurich encourages an inclusive culture. We promote equality of opportunity, value diversity and nurture a working and learning environment in which the rights and dignity of all our staff and students are respected. Visit our Equal Opportunities and Diversity website to find out how we ensure a fair and open environment that allows everyone to grow and flourish.

We look forward to receiving your online application with the following documents:

• Cover letter describing your motivation and research experience (max 1 page)
• Curriculum vitae
• Digital copies of BSc and MSc educational records
• A digital copy (PDF) of the master’s thesis (if available)
• Name and contact details of two references

Please note that we exclusively accept applications submitted through our online application portal. Applications via email or postal services will not be considered.

Review of applications will begin April 15, 2024 and will continue until the position is filled. The start date is June 1, 2024. Please contact Dr. Jan Henneberger (Jan.Henneberger@env.ethz.ch) in case of questions related to the project and/or to the position or and visit our website.

ETH Zurich is one of the world’s leading universities specialising in science and technology. We are renowned for our excellent education, cutting-edge fundamental research and direct transfer of new knowledge into society. Over 30,000 people from more than 120 countries find our university to be a place that promotes independent thinking and an environment that inspires excellence. Located in the heart of Europe, yet forging connections all over the world, we work together to develop solutions for the global challenges of today and tomorrow.