Southern Africa lies within a critical transitional zone of the global oceanic and atmospheric circulatory systems. Its response to future global climatic change and to palaeoclimatic changes (e.g. over Pleistocene glacial-interglacial cycles) has, therefore, attracted international scientific interest. The region is, however, challenging to work in, largely because its semi-arid climate does not favour the preservation of palaeoenvironmental and palaeological archives. In recent years, a novel approach to address this using the stratified communal latrines of the Rock Hyrax (Chase et al., 2012; Figure 1) - as led by the supervisory team - has resulted in the creation of remarkable high-resolution records of long-term climate change. Highlights include the recent publication of a composite 50,000 year record for the whole Namib Desert (Chase et al., 2019a).
As more hyrax midden records have been developed one of the most striking and challenging findings is the apparent spatial variability in Pleistocene-Holocene climatic trends, particularly along the southern and western margins of South Africa, close to the boundaries of the summer (tropical) /winter (temperate) rainfall zones (Figure 1; Chase and Quick, 2017; Chase et al., 2019b). This led us to hypothesise that spatial patterns in climate, particularly at millennial scales, were/are driven by complex interactions between the tropical and temperate components of the regional circulation. Understanding the how these patterns manifest in space and time will provide both key insights into the functioning of the regional climate system, and a greater understanding of likely regional manifestations of hydrological change under future warming scenarios.
The aim of this PhD is, therefore, to interrogate this spatial-temporal patterning further, in terms of: 1) enhancing the spatial resolution/sampling density of our archives to validate and refine knowledge of (palaeo)hydroclimatic gradients; 2) utilising additional proxies (leaf wax D) to unpick the causes of arid/humid trends (e.g. water sources); 3) synthesising these new site/proxies with a suite of formal time-series analyses; 4) considering these records in terms of mechanistic synoptic scale climatic systems (see Chase et al., 2017). From this, the PhD aims to provide detailed new insights into long-term interactions of Southern Hemisphere tropical-temperate climatic systems.
UK Bachelor Degree with at least 2:1 in a relevant subject or overseas equivalent.
Available for UK and EU applicants only.
Applicants must meet requirements for both academic qualifications and residential eligibility: http://www.nerc.ac.uk/skills/postgrad/
How to Apply:
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Carr, A.S., Chase, B.M., Boom, A., Medina-Sanchez, J. (2016). Stable isotope analysis of rock hyrax faecal pellets, hyraceum and associated vegetation in southern Africa: implications for dietary ecology and palaeoenvironmental reconstructions. Journal of Arid Environments 134, pp. 33-48.
Chase, B.M., Scott, L., Meadows, M.E., Gil-Romera, G., Boom, A., Carr, A.S., Reimer, P.J., Truc, L., Valsecchi, v., Quick L.J. (2012). Rock hyrax middens: a palaeoenvironmental archive for southern African drylands. Quaternary Science Reviews 56, pp. 1-19.
Chase, B.M., Chevalier, M., Boom, A., Carr A.S. (2017) The dynamic relationship between temperate and tropical circulation systems across South Africa since the Last Glacial Maximum. Quaternary Science Reviews 174, pp. 54-62.
Chase B., Quick, L.J. (2017) Agulhas forcing of Holocene climate change in South Africa’s southern Cape. Quaternary Research. 90, pp. 303-309.
Chase, B.M., Niedermeyer, E.M., Boom, A., Carr, A.S., Chevalier, M., He, F., Meadows, M.E., Ogle, N., Reimer, P.J. (2019) Orbital controls on Namib Desert hydroclimate over the past 50,000 years. (2019a) Geology, 47(9) pp. 867-871
Chase, B.M., Boom, A., Carr, A.S., Chevalier, M., Quick, L.J., Verboom, G.A., Reimer, P.J. (2019b) Extreme hydroclimatic response gradients within the western Cape Floristic Region of South Africa since the Last Glacial Maximum. Quaternary Science Reviews 219 pp. 297-307.