Welcome !
"The most awful thing in the world is not only when you realize just how much it is that you don't know, but when you become aware how far |
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| I defended my PhD in April 2006 at the "Ecole Normale Superieure" in Paris. I worked both at the "Laboratoire de Physique des Oceans" in Brest (where I lived) and at the "Laboratoire de Meteorologie Dynamique" in Paris; on the interactions between the ocean and the atmosphere in the Southern Hemisphere. The ocean currents are mainly forced by the wind blowing at the sea surface (see figures). As everybody can experience it, the dynamic of | |
 A Map of the major ocean currents of the world.
Cold oceanic currents are blue, whereas warm currents are red.
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the atmosphere is considered as very fast (days) compared to the oceanic one (months, years and more). This difference had lead to study the atmosphere considering the ocean as a fix boundary. However, the sixties have seen developing the idea that the ocean may have an influence on the atmosphere. This idea involves a more complex air-sea interaction than the simple wind forcing, as it occurs at the interannual time scale. |
| Then, I studied the patterns of interannual variability of the ocean-atmosphere coupled system in the Southern Hemisphere extratropics using a simple dynamical coupled model, in order to determine the basic physical processes of air-sea interaction independently of the tropical forcing. The figure at the right shows the most important of these patterns: the Southern Annular Mode. If you want to go further and learn more, check the PhD /air-sea interactions section. |
 Main pattern of air-sea interactions in the Southern Hemisphere (1st SVD mode between geopotential at 800hPa and the SST).
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| Now I'm a postdoc at MIT (since april 2006) and I completly changed my research area, well, may be not so much. I'm involved in the CLIMODE project (which in turn is part of CLIVAR) which means CLIvar MOde water Dynamic Experiment. The goal is to study the dynamic of the eighteen degree mode water (EDW) in the North Atlantic through analytical, numerical and observational approaches. I’m involved in the first two methods with John Marshall. So, now I use a realistic model (the MITgcm) and I focus on a small part of the ocean (Western North Atlantic) on a daily time scale.That's why it's so different from my PhD work. However, I still deal with air-sea interactions ... |
 Schematic diagram showing the interaction of a mixed layer (low PV) and the stratified interior (high PV) in a strong frontal region with outcropping isopycnal surfaces, σ, undergoing buoyancy loss, B. Eddies forming along the front play a central role in controlling horizontal fluxes through the mixed layer and two-way quasi-adiabatic exchange between the mixed layer and the interior.
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 Application of the formalism due to Walin (1982): lateral diapycnal volume flux, A, whose divergence drives subduction, is related to ‘diffusive’ fluxes, D, acting across the boundary of the shaded control volume (which includes small-scale and diapycnal eddy fluxes) and air-sea buoyancy fluxes acting across the upper surface, F = ∂B/∂σ. |
A mode water is defined as a water with specific temperature and salinity characteristics. The EDW is caracterised by a temperature of 17.8oC, a salinity of 36.5PSU and then a mean potential density of 26.45kg/m3. The mode water formation process usually occurs at the mid-end of the winter through buoyancy loss at the surface (temperature loss and/or salinity gain ) which trigger mixing and make the water homogeneous (then a mode water). The problem is about the huge difference between the estimated formation rate of EDW (15-20Sv) and the dissipation/subduction one (5Sv). Where does the difference come from ? Here is the goal of my postdoc and if you want to go further and learn more, check the Postdoc / Mode Water Formation section. |