Teaching
In addition to a short course on Ocean Dynamics I teach at
ENSTA-Paristech with Paul Billant (LadHyX), I am involved or have been involved to various degrees in several courses within the
Department of Mechanics
at the École Polytechnique. Both are located on
the campus of École Polytechnique, part of Paris-Saclay University near Paris.
at the graduate level :
Modelling projects in Biology, Ecology and Environment with
Vincent Bansaye and Yann Le Poul.
Numerical modelling and satellite remote sensing with
Hélène Chepfer (until 2012);
see some slides here .
Water Hydrodynamics with Olivier Thual (until 2010)
Climate Dynamics with Hervé le Treut
Distributed and Parallel Computing with Éric Goubault and
Sylvie Putot
at the undergraduate level :
Atmospheric and Oceanic Dynamics with Hervé le Treut ;
see some slides here .
Experimental Projects in Geophysical Fluid dynamics with Alexandre Stegner
Fluid Mechanics with Patrick Huerre (until 2006)
Continuum Mechanics with Patrick le Tallec and formerly Jean Salençon (until 2005)
My core research interests lie mainly in
geophysical fluid dynamics, from synoptic-scale,
quasi-two-dimensional turbulence to meso-scale breeze circulations
and small-scale boundary-layer turbulence.
Since 2010 I lead an effort to re-design the dynamical core of LMD-Z,
the global circulation model part of the IPSL Earth System model, with
special care given to the consistency of the mass, energy, vorticity
and angular momentum budgets, while extending the capabilities of the
dynamical core beyond the hydrostatic primitive equations and
latitude-longitude grids (DYNAMICO
project).
Earlier work of mine deals with instabilities of the Ekman boundary
layer and similar flows and multi-scale modelling of the atmosphere by
various approaches, often involving eventually the numerical solution
of idealized problems (TRANSTEK
project).
I am always looking for collaborators ranging from Master to post-doc
levels. Possible research topics include geophysical fluid dynamics,
hydrodynamic instabilities of vortices and stratified shear flow, geophysical turbulence,
numerical methods for general circulation models, idealized applications to
terrestrial and planetary circulations. Research topics typically
involve other PhD students/post-docs and/or a
number of colleagues from LadHyX, LMD and IPSL.
Various
funding opportunities exist
through local and national programmes and already funded
projects. Please get in touch with me.
The DYNAMICO project develops a new dynamical core for LMD-Z, the
atmospheric general circulation model (GCM) part of
IPSL-CM Earth System Model.
LMDZ4,
the current version of LMD-Z, has a shallow-atmosphere,
hydrostatic dynamical core. It is based on a latitude-longitude
C-grid, a hybrid pressure-based terrain-following
vertical coordinate, second-order enstrophy-conserving finite-difference
discretization and positive-definite advection. Grid refinement is implemented as a
continuous zoom via smooth grid stretching.
An extensive package of physical paramererizations is coupled to the
dynamical core. IPSL-CM is currently used to produce AR5 simulations. LMD-Z is also at the heart
of GCMs of planetary atmospheres (Mars, Venus and Titan).
It is well-known that the latitude-longitude coordinates have a strong singularity at the
poles which is undesirable in terms of both numerical stability and
computational efficiency. Regular tesselations of the sphere such as a
recursively subdivided icosahedron provide an almost-uniform grid and
a path to highly parallel computations based on domain
decomposition. LMD's logo is itself an icosahedron, evoking the
pioneering work of Robert Sadourny on the use of icosahedral grids for
solving the equations of atmospheric motion.
The primary goal of DYNAMICO is to re-formulate in LMD-Z the horizontal
advection and dynamics on a icosahedral grid, while preserving or improving their qualities
with respect to accuracy, conservation laws and wave dispersion. In turn, a new
grid refinement strategy is required. A broader goal is to
revisit all fundamental features of the dynamical core, especially the
shallow-atmosphere/traditional approximation, the vertical coordinate and the
coupling with physics. Efficient implementation on present and future
supercomputing architectures is also a key issue addressed by
DYNAMICO.
DYNAMICO is currently able to solve the hydrostatic primitive
equations and participated to the DCMIP
workshop held in August 2012 at NCAR. In the near future we will
investigate its extension to deep-atmosphere and possibly
non-hydrostatic equations following a variational approach that
naturally conserves mass, energy and, in a somewhat restricted sense,
potential vorticity. If you are not afraid of
work-in-progress, you can browse our source code .
DYNAMICO is or has been supported by the
Indo-French Centre for the Promotion of Advanced Research and by
IPSL and by the
G8 Research Councils Initiative on Multilateral Research Funding,
project ICOMEX.