How will climate change affect the stratospheric circulation?
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Competition Funded PhD Project (European/UK Students Only)
This project will use state-of-the-art modelling tools to identify the drivers of changes in the stratospheric circulation under climate change, thereby improving model projections of future ozone recovery, regional air quality, and global climate.
The stratosphere (from ~10-?50 km in altitude) is projected to undergo substantial changes in the coming decades as a result of increasing greenhouse gas concentrations and recovery of the ozone layer. A key feature of the stratosphere is the Brewer Dobson circulation (BDC), which moves stratospheric air from the tropics to the poles. This circulation pattern influences the distributions of powerful greenhouse gases, such as ozone and water vapour, in the atmosphere, and therefore plays an important role in climate. The BDC also determines the transport of ozone from the main photochemical production region in the stratosphere to the troposphere and surface, thereby influencing local air quality in populated regions. It is therefore important to understand how, and why, the BDC may change in response to current and future human activities, such as emissions of greenhouse gases.
Climate models consistently simulate an increase in the strength of the BDC under climate change. However, we do not know what factors control the magnitude, seasonality, and structure of these changes, which limits our ability to make accurate projections of the future. For example, the magnitude of the increase in the BDC varies by up to a factor of three across different models, and it is not known what determines this spread. These uncertainties have important implications for understanding future changes in the climate system, and must be understood.
The goal of this PhD project is to understand the drivers of simulated changes in the Brewer Dobson circulation under climate change. The project is designed to progress the student from analysing existing global model experiments, to formulating hypotheses of the key processes and designing and implementing bespoke model experiments to test them. Specific objectives include:
1. Identify processes that connect changes in the Brewer Dobson circulation to tropospheric climate change across a suite of climate models.
2. Design and implement experiments with a state-?of-?the-?art global climate model from the UK Met Office (HadGEM) to investigate how Brewer Dobson circulation trends depend on the representation of physical climate processes (e.g. gravity wave drag scheme).
3. Use observational datasets to constrain the physical processes identified in 1) and 2) to provide improved estimates of future changes in the Brewer Dobson circulation.
The student will work under the supervision of Dr Amanda Maycock within the Physical Climate Change and Dynamics and Clouds research groups in the School of Earth and Environment at the University of Leeds. These are world-?leading climate science groups with an excellent track record in training PhD students and conducting high impact research on global climate change and its impacts.
The student will be co-?supervised by Professor Martyn Chipperfield (SEE) and Dr Peter Hitchcock (Department of Applied Mathematics and Theoretical Physics, University of Cambridge) and will have the opportunity to undertake regular research visits to Cambridge.
The project offers the opportunity to develop expert knowledge in atmospheric and climate dynamics, as well as excellent scientific programming skills, experience of using state-?of-?the-?art supercomputing platforms, and analysis of large datasets. These skills will put the student in a strong position to pursue a successful career in academic research, but would also be highly desirable in the private sector.
Specifically, the student will receive full specialist training in:
1. developing excellent scientific programming skills for processing and visualising large datasets (e.g. Python, Fortran, R);
2. the use of cutting-?edge national supercomputing platforms (e.g. ARCHER);
3. implementing and analysing experiments in a state-?of-?the-?art global climate model.
The student will also have access to a range of tailored training workshops that cover both technical and broader professional development skills. With this training, the student will be well equipped to pursue their own research interests.
The successful candidate will have ample opportunities to present their research at international scientific conferences (e.g. EGU, AGU), and to attend summer schools and workshops relevant to the research.
A good first degree (1st or high 2.1), Masters degree or equivalent in physical sciences; such as Physics, Mathematics, Meteorology, Environmental Science, or Computer Science. Prior experience of scientific programming is desirable, but not essential.
Please visit our LARS scholarship page for more information and further opportunities: https://www.environment.leeds.ac.uk/study/postgraduate-research-degrees/lars-scholarships/
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