Fellow and Tutor in Applied Mathematics

Ian Hewitt

  • I am Associate Professor in the Mathematical Institute.

  • I work on mathematical models for Earth Science and climate-related problems.

  • My main research focus at the moment is on modelling the melting ice sheets in Antarctica and Greenland.

  • I teach a range of courses in applied maths and continuum mechanics, at Trinity and in the Mathematical Institute, as well as at international summer schools.

  • I first came to Oxford as an undergraduate, from a comprehensive school in the north of England. I worked for a while in Canada before taking up my current position.

Ian Hewitt

Teaching

At Trinity, I give tutorials in most of the applied mathematics modules in the first two years of the Mathematics degree. That includes Introductory Calculus, Geometry, Dynamics, Partial Differential Equations, Complex Analysis, Fluid Dynamics, and Mathematical Modelling in Biology. I continue to advise students in their third and fourth years, when the majority of specialist teaching is transferred to the Department. I give lectures for some of those third- and fourth-year courses, currently teaching courses in Applied Complex Variables and Mathematical Geoscience. I also lead a small research group comprising postdocs, DPhil students and Masters students.

Graph showing sea levels
i
Fresh water from the melting ice sheets emerges into the ocean from beneath the ice, forming a buoyant plume in the denser ocean water. The dynamics of these plumes exert an important control on the rate at which ice is lost and causes sea-level rise.

Research

My research involves developing and solving mathematical models to help understand problems in Earth Science, Physics and Engineering. I work together with graduate students and postdocs in the Mathematical Institute, as well as collaborating with researchers in other disciplines both in Oxford and elsewhere.

I have a particular interest in the behaviour of ice sheets, investigating both how they are currently melting, but also how they have grown and shrunk in the past – understanding this is important for forecasting and interpreting the current rapid climate change. The mathematics typically involves systems of differential equations, which we use numerical and asymptotic methods to solve – the problems often use aspects of fluid and solid mechanics as well as thermodynamics.

Another interest is in volcanology – exploring how magma is sourced and transported from inside the Earth into volcanoes. I have recently been working on how this may occur differently on other moons and exo-planets (i.e. those outside the solar system), where it may – ultimately – have something to say about extra-terrestrial life.

I also work on engineering and industrial aspects of fluid dynamics, including non-Newtonian flows, porous media flows, fluid-structure interaction, and elasto-capillarity.

You can find out more about my work here.

Glacier

Selected Publications

I. J. Hewitt, ‘Subglacial Plumes’, Annual Reviews of Fluid Mechanics. 52 (2020),145-169 [doi:10.1146/annurev-fluid-010719-060252]

D. C. Spencer, R. F. Katz, I. J. Hewitt, ‘Magmatic intrusions control Io's crustal thickness’, J. Geophys. Res. (2020) doi:10.1029/2020JE006443

E. A. Wilson, A. J. Wells, I. J. Hewitt & C. Cenedese, ‘The dynamics of a subglacial salt wedge’, Journal of Fluid Mechanics 895 (2020) [doi:10.1017/jfm.2020.308]

I. J. Hewitt, T. T. Creyts, ‘A model for the formation of eskers,’ Geophys. Res. Lett. (2019) 46, [doi:10.1029/2019GL082304]

D. I. Benn, A. C. Fowler, I. J. Hewitt, and H. Sevestre, ‘A general theory of glacier surges’, J. Glaciol. (2019) [doi:10.1017/jog.2019.62]

A. T. Bradley, F. Box, I. J. Hewitt, D. Vella, ‘Wettability-Independent Droplet Transport by Bendotaxis’, Phys. Rev. Lett. (2019) 122, 074503[doi:10.1103/PhysRevLett.122.074503]

Subjects
Dr Hewitt
ian.hewitt@trinity.ox.ac.uk

Mathematical models can be enormously powerful tools to understand and predict complex behaviour.