The School of Earth and Atmospheric Sciences Presents Dr. Felix Margirier

Decline of Deep Convection Associated to an Intense Warming and Salinification of Intermediate Waters in the Northwestern Mediterranean Sea

I just started a Postdoc here at Gatech where I am working on Mixed Layer Dynamics in the North Atlantic with Susan Lozier, but will be presenting my previous work today which ties into convection and Mixed Layer properties.

The numerous in-situ observations collected in the Mediterranean Sea over the past 15 years enable a new analysis, and the monitoring of water masses is now possible. A focus has been put on the North-Western Mediterranean Sea where deep convection occurs. Thanks to the high temporal and spatial data collected notably by gliders, an intense warming and salinification of the Levantine Intermediate Water (LIW) was evidenced. Indexes have been built to monitor the LIW and its circulation pattern was further described.

This warming and salinification concurs with the absence of deep convective events since winter 2012/2013 and the basin has been invaded at intermediate depth by the new waters. In order to better understand how deep convective events regulate the basin, the relative importance of oceanic preconditioning and of atmospheric fluxes, and the possibility of future deep convective events were discussed. For the first time, thanks to gliders, the vertical velocities,  physical and biogeochemical properties of convective plumes were characterized and are integrated in the new paradigm for deep convection which was put forward.