PhD student in atmospheric water cycle dynamics (80-100%) in Zürich

ETH Zurich is one of the world’s leading universities specialising in science and technology. It is renowned for its excellent education, its cutting-edge fundamental research and its efforts to put new knowledge and innovations directly into practice. The Atmospheric Dynamics Group, led by Heini Wernli, is an enthusiastic team that investigates the chaotic complex nature of atmospheric flow. Research is conducted to better understand the genesis, structure and interaction of different weather systems. This involves dynamically-based diagnostics, prognostic simulations with numerical models and the detailed analysis of observations.

We offer a PhD project on “Large-scale circulation drivers and stable water isotope characteristics of low-level clouds over the tropical Atlantic” (Heavy Cumuli). The Heavy Cumuli PhD candidate will be strongly involved in the international measurement campaign “Elucidating the role of cloud circulation coupling in climate” (EUREC4A, ) in Barbados in the period from 20 January to 20 February 2020. To contribute to a better physical understanding of low cloud formation and their organisation over the tropical Atlantic, we propose an interesting PhD project linking tropical low-level cloud patterns with the large-scale atmospheric circulation and the dynamics of the water cycle using isotope measurements and numerical modelling. The rationale behind using stable water isotopes as diagnostic tools to investigate low-level cloud formation, is that different types of airmass moistening and drying processes (e.g., cloud formation, convective and turbulent mixing, below-cloud evaporation, ocean evaporation) have a distinct isotope signature. Thus, the combination of stable water isotope measurements and modelling will be used to better constrain the boundary layer moisture budget and the sources of free tropospheric moisture. In the first phase of the project, the candidate will participate in the campaign preparation (August 2019 to December 2019) and campaign work (early January to 20 February 2020) of EUREC4A in Barbados. A cavity ring-down laser spectrometer (Picarro L2130) will be used for in situ airborne and ground-based measurements of stable water isotopes. The ground-based measurements will be performed at the Barbados Cloud Observatory (BCO, ). Tools for performing these measurements and post-processing of the data are readily available in the group. The campaign work will involve instrument reference measurements for calibration purposes between flights, visualisation and interpretation of IFS forecasts for the campaign planning and contributing to flight plan discussions. In the second phase of the project, simulations and sensitivity studies with the isotope-enabled numerical weather and climate prediction model COSMOiso will be performed at convection-permitting resolution for the EUREC4A campaign period, the pre-EUREC4A period 2018, as well as for the period 2015-2020. These simulations will be combined with the measurements to evaluate the model and obtain better observational constraints for the representation of airmass moistening processes in the free troposphere and the marine boundary layer in the western Atlantic. More details on the research questions and the project in general can be found .

We look forward to receiving your online application including the following documents: CV, letter of motivation, Bachelor and Master certificates and transcripts, contact information of three references. Please note that we exclusively accept applications submitted through our online application portal. Applications via email or postal services will not be considered.