PhD Studentship - Quantifying Raindrop-Freezing Fragmentation Using a Cloud Chamber and Numerical Modelling

Application deadline: All year round

Research theme: Atmospheric Science

How to apply: uom.link/pgr-apply-2425

No. of PhD positions: one

This 3.5 year PhD is funded by the Department of Earth and Environmental Sciences, available for Home students only. Tuition fees will be paid and you will receive a tax free allowance set at the UKRI rate (£19,237 for 2024/25) with and extra £1000 RTSG per annum. We expect the stipend to increase each year.

The formation and development of ice particles in clouds significantly impact precipitation processes, cloud dynamics, and radiative properties. Raindrop-freezing fragmentation, a process where supercooled raindrops freeze and shatter into smaller ice particles, plays a critical role in secondary ice production (SIP). This phenomenon can enhance ice crystal concentrations in clouds, influencing precipitation efficiency and the development of mixed-phase cloud systems. Despite its importance, the mechanisms and quantitative effects of raindrop-freezing fragmentation remain poorly understood due to the inherent challenges in observing and measuring this process in natural cloud environments.

A cloud chamber, an experimental apparatus that replicates atmospheric cloud conditions, provides a controlled environment to study raindrop-freezing fragmentation under varying thermodynamic conditions. Complementing these experiments with numerical modelling can enhance our understanding of the microphysical and thermodynamic parameters governing the fragmentation process and its implications for cloud microphysics and climate modelling.

Objectives

The primary objective of this PhD project is to quantify raindrop-freezing fragmentation using a cloud chamber and support these findings with numerical modelling. Specific aims include:

• Experimentally investigate the relationship between raindrop size, freezing rate, and fragmentation outcomes under controlled cloud chamber conditions.
• Identify the thermodynamic and microphysical parameters (e.g., temperature, humidity, collision processes) that influence fragmentation.
• Develop and validate a numerical model to simulate raindrop-freezing fragmentation and its contribution to secondary ice production.
• Integrate experimental and modelling results to improve parameterizations of SIP in atmospheric models.

Applicants should have, or expect to achieve, at least a 2.1 honours degree or a master’s (or international equivalent) in a relevant science or engineering related discipline. This project is open to home students.

Please contact the supervisor, Dr Paul Connolly - paul.connolly@manchester.ac.uk, for this project before you apply. Please include details of your current level of study, academic background and any relevant experience and include a paragraph about your motivation to study this PhD project.

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