2024-B21 Rain on Sand: Greening the Sahara

Project highlights

Use state-of-the-art high-resolution climate model simulations to further our understanding of climate change in tropical regions.
Develop links between past and future climate change helping to narrow uncertainties around future projections.
Develop potential implications for regional policy for examples in the Sahel related to the Green Wall proposal and the wider tropics through improved understanding of climate change.

Overview

Convection dominates energy and water transports in tropical regions, but it remains poorly represented in most climate models. This is most likely due to limitations in convection parameterisations which are required for models that have horizontal resolutions of greater than around 15 km, i.e. majority of global models used to project future conditions. Convection parameterisations are in many cases based on mathematical formulations that are not directly related to the underlying physical processes, and for which the controlling parameter values are often not directly observable, or are known to vary in complex ways, that are not accounted for in global models.

Several studies have shown that in convection-permitting i.e. very high-resolution models, monsoon rainfall shows much improved northward penetration, later peak intensities and different physical characteristics in response to the surrounding environment (e.g. Marsham et al 2013). This raises the prospect that explicit convection not only alters the base state through an improved representation of local processes, but that it may alter the sensitivity to large-scale changes in the environment as expected to occur in the near future.

In this project you will develop high-resolution simulations of the mid-Holocene and present-day to evaluate how the change in the monsoon in northern Africa is altered by the explicit representation of moist convection. The mid-Holocene around 6,000 years ago is an ideal testbed for models because of the observed transition to a green Sahara that has proved extremely difficult to capture in global coarse resolution models to date (e.g. Hopcroft & Valdes, 2021, Jungandreas et al., 2021, 2023). A high-resolution modelling approach will allow this project to answer directly how limitations in convective parameterisations may have hindered a full understanding of monsoons in response to climate change and to begin to unpick the complex interplay of physical and biophysical processes that control the response in these regions.

Host

University of Birmingham

Theme

Climate and Environmental Sustainability
Organisms and Ecosystems

Supervisors

Project investigator

Dr Peter Hopcroft, University of Birmingham: [email protected]

Co-investigators

Dr Jian Zhong, University of Birmingham: [email protected]

How to apply

Each host has a slightly different application process.
Find out how to apply for this studentship.
All applications must include the CENTA application form.
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Methodology

In this project you will use the Weather Research and Forecasting model (WRF) and make use of state-of-the-art computational facilities available at the University of Birmingham through the Birmingham Environment for Academic Research (BEAR) service (http://bear.bham.ac.uk). WRF is a state-of-the-art high resolution atmosphere model that will be configured in regional configuration at the km scale over North Africa. The model can therefore resolve convection in the atmosphere and is therefore able to directly represent individual storms that generate much of the rainfall in this region. The mid-Holocene is a well-established period in Earth’s history when a change in the Earth’s orbit caused widespread intensification of northern hemisphere monsoons. The project will leverage a wide range of existing mid-Holocene simulations performed with global models to drive the WRF regional model and simulate the atmospheric conditions for this past time period. The studentship will also examine the important coupling between land-surface conditions and the atmosphere through sensitivity simulations with different vegetation distributions and to test the sensitivity to resolution at the sub-km scale which has not been investigated before.

Training and skills

During this project the student will receive training in analysing and evaluating climate change simulations and in the needed computer programming skills. Prior experience of computing or coding would be helpful but is not necessary. The project would ideally suit physics, maths, engineering, geography, environmental sciences or meteorology graduates but applicants with any relevant background are encouraged.

During the project the student will have the opportunity to visit collaborators in Southampton, Bristol and elsewhere, and to present their research at conferences both within the UK and internationally.

Students will be awarded CENTA2 Training Credits (CTCs) for participation in CENTA2-provided and ‘free choice’ external training. One CTC equates to 1⁄2 day session and students must accrue 100 CTCs across the three years of their PhD.

Partners and collaboration

This studentship will benefit from a related 3-year UKRI project led from the University Southampton in collaboration with Dr Hopcroft in Birmingham and an existing PhD project on palaeo–Earth System modelling focussed on North Africa. This project will also benefit from Dr Hopcroft’s involvement in the Paleoclimate Model Intercomparison Project and its links to CMIP and IPCC. Longstanding collaborations with leading researchers elsewhere in the UK and internationally will also benefit the studentship.

Further details

Further details on how to contact the supervisor for this project and how to apply for this project can be found here:

For any enquiries related to this project please contact Peter Hopcroft ([email protected]).

To apply to this project:

You must include a CENTA studentship application form, downloadable from: CENTA Studentship Application Form 2024.
You must include a CV with the names of at least two referees (preferably three) who can comment on your academic abilities.
Please submit your application and complete the host institution application process via: https://sits.bham.ac.uk/lpages/LES068.htm. Please select the PhD Geography and Environmental Science (CENTA) 2024/25 Apply Now button. The CENTA application form 2024 and CV can be uploaded to the Application Information section of the online form. Please quote CENTA 2024-B21  when completing the application form.

Applications must be submitted by 23:59 GMT on Wednesday 10th January 2024.

Possible timeline

Year 1

Setting up regional model WRF for North Africa.

Year 2

Begin setting up sensitivity simulations to test the impacts of the paleoclimate forcings (orbit and greenhouse gas level changes) and changes to the land-surface.

Year 3

Test sensitivity to resolution and potentially integrate findings with more comprehensive global Earth System models.