Internal

Human drivers of observed changes in the West African Monsoon.

The West African Monsoon has undergone a large drought in the 1970s and 1980s. The drought was associated with a cooling of the North Atlantic sea surface temperature, as well as with increased emissions of anthropogenic aerosols from Europe. This project will use the output of a climate mode to investigate the respective roles of changes in anthropogenic aerosols, greenhouse gases concentration, and natural factors on historical Sahel precipitation.

Department: Meteorology

Supervised by: Dr Paul-Arthur Monerie and Dr. Jon Robson

The Placement Project

The drought of the 1970s and 1980s had strong impacts over Sahel, leading to significant migration, famine, and economic loses. The origin of the drought is not well understood and has been associated with both natural and human induced changes. However, climate models have large deficiencies in their representation of the West African Monsoon variability, and most models are unable to reproduce the observed changes in Sahel precipitation. Therefore, a better understanding of the causes of the historical evolution of the West African Monsoon would be useful to improve predictions of Sahel rainfall and to provide a more accurate information to decision makers. Our ongoing work has highlighted that the CESM1 climate model produces a shift from a relatively wet to a relatively dry Sahel during the early 20th century. However, this trend has not yet been understood. This project will focus on the analysis of the CESM1 climate model outputs, and particularly on a sensitivity experiment in which the time-evolution in greenhouse gases concentration have been kept constant over the 20th century, and a simulation in which the time-evolution in the anthropogenic aerosol emissions have been kept constant over the 20th century. These simulations will allow us to identify the drivers of the Sahel precipitation drying trend within this particular model.

Tasks

Task 1: The student will use the first week to read the relevant publications on Sahel precipitation variability and on the historical Sahelian drought. The first week will also allow the student to familiarise with the database and the programming language. Task 2: The student will compute analyse how precipitation has changed during the 20th century, over West Africa, and in average over the Sahel, in both observation and CESM1. The student will quantify model’s biases in precipitation. This task is expected to take one week and a half. Task 3: The student will also analyse how precipitation is changing, during the 20th century, using several sensitivity experiments that have been performed with CESM1, to identify drivers in Sahel precipitation; this would take another week. Task 4: The analysis will be focused on changes in large-scale surface air temperature, low-level wind, vertical wind and moisture flux, to provide a detailed explanation of how human activity and natural variability impacts the West African Monsoon. This task will take one week and a half. Task 5: the student will make use of the large number of simulations (i.e. 20) of CESM1 to compare the impacts of anthropogenic aerosols (or greenhouse gases) to changes that are associated with the stochastic internal climate variability, to assess robustness in the impacts of the external forcing. In the task 5 the student will only focus on area-averaged Sahel precipitation, and will take another week. However, should the student have spare time within the six-week period, there is plenty of scope for further investigation.

Skills, knowledge and experience required

As the bulk of this project involves analysing data, experience with a programming language would be an advantage (e.g. Matlab, NCL, Python), but analysis code will be provided. The student should have an interest in meteorology/climatology, particularly of the tropics.

Skills which will be developed during the placement

Throughout this project, the student will have the opportunity to gain knowledge in climate dynamics, tropical meteorology and understanding impacts of internal climate variability and external forcing on climate, with a focus on Sahel precipitation. The project will also allow the student to develop or enhance their data analysis and scientific programming skills, with support from the supervisors. As an optional output the student will have the opportunity to work on communication skills, preparing a presentation for a scientific audience.

Place of Work

Within the Department of Meteorology, Whiteknights campus

Hours of Work

Preferred hours are 9am-5pm, Monday to Friday, but could be negotiated if needed.

Approximate Start and End Dates (not fixed)

Wednesday 01 July 2020 - Sunday 23 August 2020

How to Apply

The deadline to apply for this project is Monday 11th May at 5pm. Students should submit their CV and Cover Letter directly to the Project Supervisor (click on supervisor name at the top of the page for email). Successful candidates will then be invited to interview.


Return to Placements List

Page navigation