Mediterranean sea-surface and deep responses to large-scale atmospheric forcing in evaluation Med-Cordex simulations

The Mediterranean Sea is one of the few regions in the world where ocean deep convection events occur, contributing to trigger the local thermohaline circulation. The variability of this circulation is typically affected by large-scale atmospheric modes of variability of Atlantic and Eurasian origin, like, e.g., the North Atlantic Oscillation (NAO), the Eastern Atlantic pattern (EA), the Eastern Atlantic Western Russian pattern (EAWR) and the Scandinavian pattern (SCA). 

Whereas previous studies assessed the impacts of these modes on air-sea heat and freshwater fluxes over the Mediterranean Sea, few studies explored the propagation of these signals from the surface towards the interior of the Mediterranean Sea and mostly they relied on the use of single model simulations.

In this contribution we investigate the Mediterranean thermohaline response to winter forcing from NAO, EA, EAWR and SCA using a multi-model analysis of evaluation simulations belonging to the Med-Cordex initiative. We present results from a composite analysis around strong positive and negative phases of these modes to track the propagation of the associated signals from the sea surface towards the Mediterranean interior in key regions such as the South Adriatic, the Aegean and Levantine Seas and the Gulf of Lion. 

Different simulations show only a partial agreement as far as the identification of the modes mostly contributing to deep water formation is concerned.