School of Earth Sciences

Does the likelihood of a tropical cyclone change

following a large volcanic eruption?

Co-Supervisors:
Dr Erica Hendy (School of Earth Sciences/School of Biological Sciences),
Dr Alison Rust (School of Earth Sciences)
and Dr Caroline Williams (Senior Lecturer in Latin American Studies, Department of Hispanic, Portuguese and Latin American Studies, Faculty of Arts)

Global climate is sensitive to volcanic eruptions, in particular explosive tropical eruptions that inject long-lived sulfate aerosols into the stratosphere. For example, an eruption the size of Mt Pinatubo, 1991 (peak dimming of about 3.7 W.m-2), can increase the likelihood and amplitude of an El Niño event within a year of the eruption according to 20th Century and palaeo-reconstructions [1]. El Niño events are a rearrangement of global rainfall and temperature patterns, however, the dramatic reduction in global freshwater runoff during the 1992 El Niño event was directly attributed to the Mt Pinatubo eruption in 1991 [2]. Recently, radiative forcing by aerosols has been linked to further anomalies in the hydrological cycle, including both the intensification and dampening of tropical cyclone activity in Arabian Sea and North Atlantic, respectively [3, 4]. Direct observations of aerosol-hydrological cycle and volcanic-climate interactions are limited to the last few decades and a few moderate 20th Century eruptions. Palaeoclimate sources, in combination with historical sources documenting the occurrence and effects of tropical cyclones, can extend this perspective and enable us to investigate the impact of much larger eruptions such as Tambora in 1815AD or Huaynaputina in1600AD (peak dimming >5W.m-2).

In this PhD project the student will examine the sensitivity of tropical cyclone activity to aerosol and radiative forcing using documentary records. The wealth of archival material from the Spanish colonial era collected from the Caribbean, Latin America and Philippines is proving particularly valuable for reconstructing past tropical cyclone activity [e.g. 5, 6]. Strategic examination of archival material, including extended visits to the Archivo General de Indias (AGI) in Seville, will be supervised and guided by Dr Williams (a historian of colonial Spanish America with extensive experience of the colonial archive). Current hypotheses for how aerosols and tropical cyclone activity are linked, and the relationships identified under the current era of global climate change [e.g. 7], will be tested using target volcanic events selected from the 17th-19th centuries. Supervision of the palaeoclimate and volcanic aspects of the project will be provided by Drs Hendy and Rust, respectively. In order to inform insurance and risk end users, the output will be a likelihood of enhanced or suppressed tropical cyclone activity under specific volcanic aerosol and radiative forcing scenarios. The student will acquire strong skills in data management and visualisation, risk and uncertainty, numeracy and research communication; all identified by NERC as critical skills gaps in the UK environment sector.

A strong applicant will have a background in earth sciences, with a particular interest in climatology and volcanology, an understanding of statistics, and an enthusiasm for history. The ideal candidate will be fluent in Spanish; alternatively a demonstrated ability to learn languages will be essential and an intensive course on Spanish language will be offered at the start of the PhD.

This is a multi-disciplinary collaborative research project that will cross-link the School of Earth Sciences (Faculty of Science) and the Department of Hispanic, Portuguese and Latin American Studies in the School of Modern Languages (Faculty of Arts). Both Schools provide exposure to unique postgraduate learning opportunities and active postgraduate communities. It is anticipated that the student will be active in the vibrant Volcanology research group, engage with the BRIDGE group which is part of the Cabot Institute, and take advantage of the thriving research culture in Latin American studies.

Further reading:

1. Emile-Geay, J., et al., Volcanoes and ENSO over the past millennium. Journal of Climate, 2008. 21 (13): p. 3134-3148.
2. Trenberth, K.E. and A. Dai, Effects of Mount Pinatubo volcanic eruption on the hydrological cycle as an analog of geoengineering. Geophysical Research Letters, 2007. 34 (15): p. 5.
3. Evan, A.T., et al., Arabian Sea tropical cyclones intensified by emissions of black carbon and other aerosols. Nature, 2011. 479 (7371): p. 94-U119.
4. Evan, A.T., et al., The Role of Aerosols in the Evolution of Tropical North Atlantic Ocean Temperature Anomalies. Science, 2009. 324 (5928): p. 778-781.
5. Garcia-Herrera, R., et al., New records of Atlantic hurricanes from Spanish documentary sources. Journal of Geophysical Research-Atmospheres, 2005. 110 (D3).
6. Garcia-Herrera, R., et al., Identification of Caribbean basin hurricanes from Spanish documentary sources. Climatic Change, 2007. 83 (1-2): p. 55-85.
7. Sriver, R.L., CLIMATE CHANGE Man-made cyclones. Nature, 2011. 479 (7371): p. 50-51.