Professor David Gubbins

Profile

Research Interests

Geomagnetism, theoretical seismology, subduction zones, inverse theory.

Biography

Did Physics at Cambridge and a PhD on 'Geomagnetic Dynamos', in the Department of Geodesy and Geophysics, Cambridge. His main research interest remains the origin of the Earth's magnetic field and PhD projects are offered this year in both observational and theoretical aspects of geomagnetism. A comprehensive dataset of magnetic observations from the last 400 years has been collected and resides on the computer system in the School; it is still being added to and provides the basis for several research studies. The research emphasis is now moving towards understanding long term behaviour of the magnetic field through dynamo models and interpretation of the paleomagnetic record.

Further interests are in seismology and all aspects of theoretical geophysics, both pure and applied.

After my PhD I spent 3 years in the USA (Boulder, Colorado; MIT; UCLA) before returning to Cambridge where I worked at the Department of Geodesy and Geophysics (later Earth Sciences). I moved to Leeds as Head of Geophysics in 1989 and played a major role in the expansion of the subject within the School.

I retired in 2009 to enjoy a few years of sailing. I remain research-active, spending summer months in Leeds. I spend the autumn at the Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California at San Diego, where I am a Research Associate, and a month in the winter at the University of Sydney, where I am a Visiting Professor in the Geosciences and Mathematics Departments.

I am an Honorary Professor at the State Key Laboratory of Lunar and Planetary Science, Macao University of Science and Technology, Macao and spend October-December there.  SKL Planets will run Macao’s first satellite mission, to measure magnetic field and solar radiation focussed on the South Atlantic Anomaly and Space Weather, and plans several more satellites in the near future. We are actively hiring at all levels from PhD students to Professor.  

 The rest of the time finds me sailing up and down the west coast of Central America, when I can be difficult to contact.

Research interests

My main research interest has always been the origin of the Earth's magnetic field, which has led me into numerous theoretical and data-oriented projects. I have also done seismology and a range of theoretical projects, particularly in inverse theory.

Current projects include:

Origin of the Earth's Magnetic field. I use the Leeds Dynamo Code to simulate geomagnetic behaviour over millions of years and compare with geomagnetic and paleomagnetic records. The paleomagnetic work is done in collaboration with Prof. Cathy Constable at Scripps.

Power Source for the Earth's Dynamo. Using determinations of material properties of iron alloys from modern mineral physics calculations, we have recalculated the thermal history of the Earth's core. The Earth has had to cool faster than we thought. We have now moved on to studying the core-mantle boundary, its chemical equilibrium, and consequences for core and mantle evolution. Done in collaboration with Chris Davies (SEE) and Dario Alfe, Monica Pozzo (University College, London).

Crustal and Lithospheric Magnetisation. I developed a new approach to analysing the magnetisation of crust and lithosphere and applied it to global models of the Earth (S Masterton, now with the company GeTech); the work is extended to regional studies with industrial applications; the  global model has been refined to include subduction zones; plans in the future are to include LIPS in the ocean, and Antarctica. Done in collaboration with Prof David Ivers, Dietmar Mueller, and Simon Williams at University of Sydney. 

Magnetic Field of Mars. Funded by the Macao foundation, which provides a student and postdoc, this project will apply the new methods described above to study the history of Mars’ core and ancient dynamo and the hemispheric nature of the magnetisation in the crust, particularly in relation to impacts. Led by myself and Professor Keke Zhang, Director of SKL-Planets.

Satellite Mission to Study the South Atlantic Anomaly. Plans are currently underway for SKL-Planets to launch a magnetic satellite in  2021. The objective is to complement the current constellation of ESA magnetic satellites, SWARM, and continue monitoring after SWARM reaches the end of its active life, possibly being augmented by a further constellation from Macao. It will be the first such satellite in a low-latitude orbit, giving better coverage over the SAA and equatorial regions at the expense of polar coverage. It will measure all 3 components of magnetic field as well as solar radiation. It will pass over the SAA more frequently than SWARM because of its orbit, and provide good time coverage in the equatorial region. We hope to improve understanding of the SAA and the damaging effects of radiation on communication satellites and ground equipment. It will contribute to improved models of the Earth’s main magnetic field as well as its secular variation and external magnetic phenomena.

• Rapid Dynamics in the Earth's Core

Qualifications

• BA (1968) Natural Sciences Tripos (Theoretical Physics), University of Cambridge
• MMaths (1969) Part III of the Mathematics Tripos
• PhD (1972) 'Geomagnetic Dynamos', University of Cambridge

Professional memberships

• Fellow, American Geophysical Union (1985)
• Fellow of the Royal Society (1996)
• Fellow, Institute of Physics (1996)
• Honorary Member, European Geophysical Union (2010)
• Foreign Member, Norwegian Academy of Arts and Sciences

Student education

On arrival at Leeds in 1989 I devised new courses for the Geophysics BSc and Exploration Geophysics MSc. These are largely in place today. The Mathematics courses, after moderation by other departments, were taught outside the (then) Department of Earth Sciences. I taught courses on data analysis, EARS2190, 3250 and 5115, for many years and wrote the text book “Time Series Analysis and Inverse Theory for Geophysicists” (Cambridge Univ. Press) that is based on these courses. These courses were revolutionary in being some of the first to use classrooms equipped with computers for the students to solve practical problems. 

I no longer teach in retirement but have just started a course on data analysis for planetary scientists at Macao University of Science and Technology, with some 26 Masters and PhD students enrolled.

Research groups and institutes

• Institute of Geophysics and Tectonics