Dr Simon Clarke - Researcher Profile

Simon Clarke

Address

School of Mathematical Sciences
Building 28, Clayton

Contact Details

Tel: +61 3 9905 4421

Fax: +61 3 9905 3867

Email: simon.clarke@sci.monash.edu.au

Web: http://www.maths.monash.edu.au/~src/index.shtml


Biography

The spectacular roll of cloud known as Morning Glory that stretches from horizon to horizon over Cape York Peninsula; the meeting of dense, salty water from the Mediterranean with the lighter waters of the Atlantic in the Strait of Gibraltar; the Gulf Stream that becomes increasingly unstable as it leaves the east coast of America and heads for Britain; the rough waters in Drake Passage at the southernmost tip of South America; the Antarctic Circumpolar Current, which links the Indian, Pacific and Atlantic oceans – these are the kind of natural phenomena that fascinate Dr Simon Clarke.

 

Simon’s interest lies not in studying these things as they occur – his is a desk job – but in using numerical modelling to find out why they happen and what effect they have.  The common element in this list is waves:  not the kind you see crashing on a beach, but “large amplitude waves”, which are caused by changes in density in air or water (internal waves) or by the changes in rotation on the earth’s surface (Rossby waves).

Just like waves on the ocean, these waves can grow and change and break. Cyclones, for example, start as Rossby waves in the atmosphere and eventually form closed loops of rotation which we see as weather systems.

Both kinds of waves play a large role in the transfer of mass and heat within the atmosphere and the oceans. Understanding their dynamics is important for weather prediction and deeper knowledge of climate change.

Simon is also interested in how topography affects not only waves, but currents and eddies: what are the dynamics, for example, when a current is forced through the restricting Drake Passage?

A mathematician and computer programmer, Simon’s work involves developing models that will increase our understanding of causes and effects. 

“You can use very simple models to study fairly complex phenomena,” he says. “That’s what usually occurs in mathematics because, to make headway in studying complicated phenomena, you’ve got to make approximations and you work incrementally.”

Simon’s “simple models” feed into a hierarchy of increasingly complex ones.

“The hope is that we can use these simplified dynamics models to understand what’s occurring in intermediate complexity models and that can then be used to understand what’s happening in more complex models,”  he says.

This work can ultimately inform such things as the global circulation models used by the Bureau of Meteorology to predict weather, or by the Intergovernmental Panel on Climate Change in its research. But the importance and relevance of understanding waves goes beyond even global weather systems.

The questions he is trying to answer are crucial to everyday living. The kind of equations Simon uses to describe waves also describe light travelling along optical fibres, the basis of our telecommunications system. And they stretch through the solar system: waves also explain Jupiter’s Great Red Spot, a persistent anti-cyclonic storm that can be seen from Earth.

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Research & Supervision Interests

    Evolution of non-linear waves and their application to geophysical flows. Topics of research in this field include; effect of shear of finite-amplitude waves, trapping of non-linear internal waves, internal solitary waves with oscillatory tails, dynamics of finite-amplitude interfacial waves, non-linear critical layers, non-linear wave groups.

Keywords

convection numerical meteorology weather forecasting meteorology, convection weather forecasting numerical modelling meteorology, density-stratified fluid flows internal waves fluid flow instability

Qualifications

GRADUATE CERTIFICATE HIGHER EDUCATION
Institution: Monash University
Year awarded: 2005
SCIENCE
Institution: University of Western Australia
Year awarded: 1992
SCIENCE - HONOURS
Institution: Adelaide University
Year awarded: 1987

Publications

Books

Clarke, S.R., Grimshaw, R.H.J., Miller, P., Pelinovsky, E., Talipova, T.G., 1999, On the Initial Value Problem for the Modified Korteweg-de Vries Equation, Dept of Maths & Stats, Monash University, Clayton Vic Australia.

Clarke, S.R., Grimshaw, R.H.J., Malomed, B., 1999, Soliton formation from a pulse passing the zero-dispersion point in a nonlinear Schrodinger equation, Dept of Maths & Stats, Monash University, Clayton Vic Australia.

Clarke, S.R., Grimshaw, R.H.J., 1999, Weakly-nonlinear internal wave fronts in a contraction, Dept. of Maths & Stats, Monash University, Clayton Vic Australia.

Clarke, S.R., Johnson, E.R., 1998, Finite-amplitude topographic Rossby waves in a channel, Dept of Mathematics & Statistics, Monash Universiy, Clayton Vic Australia.

Clarke, S.R., Clutterbuck, J., Grimshaw, R.H.J., Malomed, B., 1998, Passage of a wave pulse through a zero-dispersion point in a nonlinear-Schrodinger equation, Dept of Mathematics & Statistics, Monash Universiy, Clayton Vic Australia.

Clarke, S.R., Grimshaw, R.H.J., 1998, The effect of weak shear on finite amplitude internal solitary waves, Dept of Mathematics & Statistics, Monash Universiy, Clayton Vic Australia.

Journal Articles

Ee, B.K.W., Clarke, S.R., 2008, Weakly dispersive hydraulic flows in a contraction - Nonlinear stability analysis, Wave Motion [P], vol 45, issue 7-8, Elsevier Science BV, Amsterdam Netherlands, pp. 927-939.

Akylas, T.R., Grimshaw, R.R.H., Clarke, S.R., Tabaei, A., 2007, Reflecting tidal wave beams and local generation of solitary waves in the ocean thermocline, Journal of Fluid Mechanics, vol 593, Cambridge University Press, Cambridge UK, pp. 297-313.

Ee, B.K.W., Clarke, S.R., 2007, Weakly dispersive hydraulic flows in a contraction: Parametric solutions and linear stability, Physics of Fluids, vol 19, issue 5, American Institute of Physics, New York USA, pp. 56601-1-56601-11.

Clarke, S.R., Malomed, B., Grimshaw, R.R.H., 2002, Dispersion management for solitons in a Korteweg-de Vries system, Chaos, vol 12, issue 1, American Institute of Physics, New York NY USA, pp. 8-15.

Clarke, S.R., Miller, P., 2002, On the semi-classical limit for the focussing nonlinear Schrdinger equation: sensitivity to analytic properties of the initial data, Proceedings of the Royal Society of London A, vol 458, The Royal Society, London UK, pp. 135-156.

Maslowe, S.A., Clarke, S.R., 2002, Subcritical Rossby waves in zonal shear flows with nonlinear critical layers, Studies in Applied Mathematics, vol 108, issue 1, Blackwell Publishers, Massachusetts USA, pp. 89-103.

Miller, P., Clarke, S.R., 2001, An exactly solvable model for the interaction of linear waves with Korteweg-De Vries solitons, SIAM Journal on Mathematical Analysis, vol 33, issue 2, Society for Industrial & Applied Mathematics, USA, pp. 261-285.

Johnson, E.R., Clarke, S.R., 2001, Rossby wave hydraulics, Annual Reviews of Fluid Mechanics, vol 33, Annual Reviews Inc., CA USA, pp. 207-230.

Clarke, S.R., Johnson, E.R., 2001, The weakly nonlinear limit of forced Rossby waves in a stepped channel, Proceedings of the Royal Society of London Series A, vol 457, The Royal Society, London UK, pp. 2361-2378.

Clarke, S.R., Miller, P., Grimshaw, R.H.J., Pelinovsky, E., Talipova, T.G., 2000, On the generation of solitons and breathers in the modified Korteweg-de Vries equation, Chaos, vol 10 issue 2, American Institute of Physics, www.aip.org, pp. 383-392.

Clarke, S.R., Grimshaw, R.H.J., 2000, Weakly nonliner internal wave fronts trapped in contractions, Journal of Fluid Mechanics, vol 415, Cambridge University Press, Cambridge UK, pp. 323-345.

Johnson, E.R., Clarke, S.R., 1999, Dispersive effects in Rossby-wave hydraulics, Journal of Fluid Mechanics, vol 401, Cambridge University Press, Cambridge UK, pp. 27-54.

Clarke, S.R., Johnson, E.R., 1999, Finite amplitude topographic Rossby waves in a channel, Physics of Fluids, vol 11 issue 1, American Institute of Physics, www.aip.org, pp. 107-120.

Clarke, S.R., Clutterbuck, J., Grimshaw, R.H.J., Malomed, B., 1999, Passage of wave pulse through a zero-dispersion point in the nonlinear Schrodinger equation, Physics Letters A, vol 262, Elsevier, www.elsevier.nl, pp. 434-444.

Clarke, S.R., Grimshaw, R.H.J., 1999, The effect of weak shear on finite-amplitute internal solitary waves, Journal of Fluid Mechanics, vol 395, Cambridge University Press, Cambridge UK, pp. 125-159.

Conference Proceedings

Clarke, S.R., Johnson, E.R., 2001, Supercritical leaps in two-layer hydraulics, Proceedings of the 14th Australasian Fluid Mechanics Conference, 10/12/01 to 14/12/01, Dept. of Mech. Eng., Adelaide University, Adelaide SA Australia, pp. 573-576.

Clarke, S.R., Grimshaw, R.H.J., Malomed, B., 2000, Soliton formation in a variable coefficient nonlinear Schrodinger equation, Mathematical and numerical aspects of wave propogation, Santiago de Campostela Spain 10-14 July 2000, Society for Industrial and Applied Mathematics, Philadelphia USA, pp. 280-284.

Grants

Title:
Predicting Organized Tropical Convection ID: DP0558793.
Investigators:
Reeder, M, Clarke, S, Low, D, Holland, G, Smith, R
Funding:
(2005 - 2009). Australian Research Council (ARC).
(2005 - 2009). Monash University.
(2005 - 2010). University of New South Wales.