Details of Award
NERC Reference : NE/M010384/1
The origins of extreme volcanic ash shapes and implications for ash cloud forecasts
Training Grant Award
- Lead Supervisor:
- Professor KV Cashman, University of Bristol, Earth Sciences
- Grant held at:
- University of Bristol, Earth Sciences
- Science Area:
- Atmospheric
- Earth
- Overall Classification:
- Atmospheric
- ENRIs:
- Environmental Risks and Hazards
- Science Topics:
- Tropospheric Processes
- Geohazards
- Volcanic Processes
- Abstract:
- The 2010 eruption of Eyjafjallajokull, Iceland, highlighted the potential socio-economic costs of explosive volcanic eruptions, even to countries without active volcanoes such as the UK. Despite its modest size, the eruption dispersed volcanic ash over three continents and closed European airspace for a week, stranding thousands of passengers, costing airlines over 1.1 billion GBP. As a consequence of this eruption, a non-zero threshold of ash concentration has been established to define no-fly zones. The accuracy of ash forecasts thus affects businesses dependent on air transport of people and goods. The Met Office in Exeter is the authorised Volcanic Ash Advisory Centre (VAAC) responsible for providing forecasts on the movement of ash clouds over the northeast Atlantic, Iceland and the UK. To make these forecasts the VAAC uses a computer model called NAME developed and maintained by the Met Office. A key component of NAME is predicting the rate of particle fall from the ash cloud. To do this, NAME assumes that particles are spherical; some volcanoes, however, repeatedly produce ash particles with extreme non-spherical shapes, including needles and flat plates. Much like falling leaves, non-spherical shapes will affect how fast ash falls, and so how far it travels through the atmosphere before landing on the ground. This studentship will combine fieldwork, experiments and modeling to improve NAME's capability to forecast the dispersion of ash clouds by accounting for non-spherical shapes of ash particles. At the University of Bristol the student will determine controls on extreme ash shapes by studying ash from eruptions of a range of styles, intensities and chemical compositions. Particle shape will be measured in two- and three-dimensions by a combination of optical microscopy, scanning electron microscopy and X-ray imaging. The student will also collect ash from Katla volcano in southern Iceland for a more detailed case study. This frequently active volcano erupts magma of a range of compositions and eruption styles that produce highly variable ash shapes, including silicic eruptions with needle-shaped ash. Once ash shapes have been quantified, the student will observe ash falling in the laboratory with high-speed video to determine how shape affects the velocity and orientation of ash as it falls through air. In collaboration with the Met Office, the results of the experiments will be incorporated into NAME to account for the fall velocity of non-spherical particles. The student will run sensitivity tests to assess the effects of ash shape on NAME forecasts of volcanic ash cloud transport and then run a set of forecasts to explore likely scenarios for eruptions of Katla volcano in Iceland. Additionally, the student will evaluate the effect of extreme ash shape on standard methods of assessing ash size distributions from both aircraft and satellite observations. For this purpose, the student will measure the apparent sizes of well-characterized ash using a laser diffraction particle analyser at the University of Bristol and then work with Met Office staff to explore implications for nonlaboratory methods used to assess ash sizes during eruptions. The studentship will last 3.5 years (including 4 months at the Met Office). Training in fieldwork, physical volcanology, microbeam analysis, grain size analysis, laboratory experiments, teaching, scientific writing and public engagement will be provided by the University of Bristol. The Met Office will train the student to use NAME (Numerical Atmospheric-dispersion Modelling Environment), the programme used to forecast ash dispersal. The student will also have access to a range of scientific and programming courses in the Met Office college such as FORTRAN, Python, meteorology, statistics and geophysical fluid dynamics. Early in the studentship all of the supervisors and the student will meet to evaluate their background and experience and consequent training needs.
- NERC Reference:
- NE/M010384/1
- Grant Stage:
- Completed
- Scheme:
- DTG - directed
- Grant Status:
- Closed
- Programme:
- Industrial CASE
This training grant award has a total value of £85,122
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - RTSG | Total - Student Stipend |
|---|---|---|
| £16,584 | £11,000 | £57,536 |
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