Olivier ARZEL

Climate Change Research Centre
Faculty of Science
The University of New South Wales
Sydney, NSW, Australia, 2052
Phone: +61 02 9385 8965
Fax: +61 02 9385 8969
Contact: o.arzel@unsw.edu.au

Research interests:

Stability of the Atlantic Meridional Overturning Circulation
Decadal to millennial-scale climate variability
High latitude climate change

Oceanographic experience:

June 2006 to present: Post-doc at the Climate Change Research Centre, UNSW, Sydney, Australia	Stability and millennial-scale variability of the Atlantic Meridional Overturning Circulation.
March 2004 to March 2006: Post-doc at the Institut d'Astronomie et de Géophysique Georges Lemaître, UCL, Louvain-La-Neuve, Belgium	Climate change in polar regions: Assessment of current AOGCMs to reproduce the observed sea ice cover over the past century, and analysis of Arctic and Antarctic sea ice projections for the 21^st century. This research was conducted within the framework of the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC AR4). Investigating the causes and impacts of changes in the Arctic freshwater budget over the 20^th and 21^st centuries in the IPSL french climate system model. Special emphasis was placed upon (1) the mechanisms that drive the liquid freshwater export from the Arctic basin to the subpolar North Atlantic through Fram Strait, and (2) the interannual variability of the deep winter oceanic convection in the Nordic Seas. This part of my research was a component of the european ENSEMBLES project.
October 2001 to February 2004: PhD student at the Laboratoire de Physique des Océans , UBO, Brest, France	Decadal to interdecadal variability of thermohaline and wind-driven circulations in a variety of idealized climate models (ocean only and coupled ocean-atmosphere models). A part of the work has dealt with the influence of peculiar surface boundary conditions (SBCs) on the structure and properties of the interdecadal variability of the meridional overturning circulation in a stand-alone planetary geostrophic ocean model. The SBCs of interest were the mixed (constant freshwater flux and SST restoring, MBC) and flux boundary conditions (steady surface heat and freshwater fluxes, FBC). Objectives diagnostics, based on analyses of density variance budget and structure of perturbations, were proposed to distinguish one type of oscillation versus the other. Robustness of ocean modes associated with each of these SBCs to the coupling with a zonally-averaged statistical-dynamical moist atmosphere model was further explored. Results showed that on long timescales the ocean governs climate variability, which in the present case appears to be of FBC origin. PhD advisors: A. Colin de Verdière (LPO/UBO) and T. Huck (LPO/UBO)
October 2000 to June 2001: Master at the Laboratoire de Physique des Océans , UBO, Brest, France	Classes in Physical Oceanography and Meteorology. Three months intern with T. Huck on mechanisms of decadal variability of wind-driven gyres in a reduced gravity ocean model coupled to an EBM atmosphere including eddy momentum fluxes parameterization.
June 2000 to September 2000: Vacation at the EPSHOM, Brest, France.	Turn-table experiments. Interaction between vortices and sea-mount in a stratified fluid.

June 2006 to present:

Post-doc at the

Climate Change Research Centre, UNSW, Sydney, Australia

Stability and millennial-scale variability of the Atlantic Meridional Overturning Circulation.

March 2004 to March 2006:

Post-doc at the

Institut d'Astronomie et de Géophysique Georges Lemaître, UCL, Louvain-La-Neuve, Belgium

Climate change in polar regions:

Assessment of current AOGCMs to reproduce the observed sea ice cover over the past century, and analysis of Arctic and Antarctic sea ice projections for the 21^st century. This research was conducted within the framework of the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC AR4).

Investigating the causes and impacts of changes in the Arctic freshwater budget over the 20^th and 21^st centuries in the IPSL french climate system model. Special emphasis was placed upon (1) the mechanisms that drive the liquid freshwater export from the Arctic basin to the subpolar North Atlantic through Fram Strait, and (2) the interannual variability of the deep winter oceanic convection in the Nordic Seas. This part of my research was a component of the european ENSEMBLES project.

October 2001 to February 2004:

PhD student at the

Laboratoire de Physique des Océans , UBO, Brest, France

Decadal to interdecadal variability of thermohaline and wind-driven circulations in a variety of idealized climate models (ocean only and coupled ocean-atmosphere models).

A part of the work has dealt with the influence of peculiar surface boundary conditions (SBCs) on the structure and properties of the interdecadal variability of the meridional overturning circulation in a stand-alone planetary geostrophic ocean model. The SBCs of interest were the mixed (constant freshwater flux and SST restoring, MBC) and flux boundary conditions (steady surface heat and freshwater fluxes, FBC). Objectives diagnostics, based on analyses of density variance budget and structure of perturbations, were proposed to distinguish one type of oscillation versus the other. Robustness of ocean modes associated with each of these SBCs to the coupling with a zonally-averaged statistical-dynamical moist atmosphere model was further explored. Results showed that on long timescales the ocean governs climate variability, which in the present case appears to be of FBC origin.

PhD advisors: A. Colin de Verdière (LPO/UBO) and T. Huck (LPO/UBO)

October 2000 to June 2001:

Master at the

Laboratoire de Physique des Océans , UBO, Brest, France

Classes in Physical Oceanography and Meteorology. Three months intern with T. Huck on mechanisms of decadal variability of wind-driven gyres in a reduced gravity ocean model coupled to an EBM atmosphere including eddy momentum fluxes parameterization.

June 2000 to September 2000:

Vacation at the

EPSHOM, Brest, France.

Turn-table experiments. Interaction between vortices and sea-mount in a stratified fluid.

Publications:

[9] Arzel, O., A. Colin de Verdière and M. H. England (2009): The role of oceanic heat transport and wind-stress forcing in abrupt millennial-scale climate transitions, submitted to Journal of Climate, preprint

[8] Arzel, O., M. H. England and O. Saenko (2009): The impact of the wind-stress feedback on the thermohaline circulation hysteresis, submitted to Journal of Climate, preprint

[7] Arzel, O., M. H. England and W. P. Sijp (2008): Reduced stability of the Atlantic Meridional Overturning Circulation due to wind-stress feedback during glacial times, Journal of Climate, 21, 6260-6282, pdf

[6] Arzel, O. T. Fichefet, H. Goosse and J-L. Dufresne (2008): Causes and impacts of changes in the Arctic freshwater budget during the 20^th and 21^st centuries in an AOGCM, Climate Dynamics, 30, 37-58, pdf

[5] Arzel, O., A. Colin de Verdière and T. Huck (2007): On the origin of interdecadal oscillations in a coupled ocean-atmosphere model, Tellus A, 59, 367-383, pdf

[4] H. Goosse, O. Arzel, J. Luterbacher, M. E. Mann, H. Renssen, N. Riedwyl, A. Timmermann, E. Xoplaki, and H. Wanner (2006): The origin of the European "Medieval Warm Period", Climate of the Past, 2, 99-113, pdf

[3] Arzel O., T. Huck and A. Colin de Verdière (2006): The different nature of the interdecadal variability of the thermohaline circulation under mixed and flux boundary conditions, Journal of Physical Oceanography, 36, 1703-1718, pdf

[2] Arzel, O., T. Fichefet and H. Goosse (2006): Sea ice evolution over the 20^th and 21^st centuries as simulated by current AOGCMs, Ocean Modelling, 12, 401-415, pdf

[1] Arzel, O. and T. Huck (2003) Decadal oscillations in a simplified coupled model due to unstable interactions between zonal winds and ocean gyres, Dynamics of Atmospheres and Oceans, 37, 245-270, pdf

PhD Thesis:

Arzel, O. (2004) Mécanismes de variabilité climatique interdécennale dans des modèles idealisés, Thèse de doctorat de l'Université de Bretagne Occidentale, 214 pages, pdf

Others:

Fichefet, T., O., Arzel and H. Goosse (2008): On the ability of current atmosphere-ocean general circulation models to predict the evolution of sea ice, Climate and Cryosphere Newsletter, Ice and Climate, Global Prediction of the Cryosphere, 10, 5-6, pdf

Dufresne, J-L., D. Salas y Mélia, S. Denvil, S. Tyteca, O. Arzel, S. Bony, P. Braconnot, P. Brockmann, P. Cadule, A. Caubel, F. Chauvin, M. Déqué, H. Douville, L. Fairhead, T. Fichefet, M.-A. Foujols, P. Friedlingstein, J.-Y. Grandpeix, J.-F. Guérémy, F. Hourdin, A. Idelkadi, G.Krinner, C. Lévy, G. Madec, P. Marquet, O. Marti, L. Musat, S. Planton, J.-F. Royer, D. Swingedouw, A. Voldoire (2007): Simulation du climat récent et futur par les modèles du CNRM et de l'IPSL, La m�t�orologie, 55, 45-59, pdf

Salas y M�lia D., Genthon C., avec la contribution de Arzel O., Cassou C., V. Guemas, G. Krinner, M. Minveille et D. Swingedouw (2007) Chapitre 6 du Livre blanc ESCRIME, Études des simulations climatiques réaliséees par l'IPSL et Météo France, pdf

Salas y M�lia D., C. Genthon, O. Arzel, C. Cassou, V. Guemas, G. Krinner, M. Minveille et D. Swingedouw (2007) R�gions polaires, cryosph�re et circulation thermohaline. La m�t�orologie, 56, 33-39, pdf