Monitoring open-ocean deep convection from space. Geophys

At the origin of deep water formation in the world’s oceans, deep convection is a key-process of the oceanic circulation. It occurs in a few regions, including the Northwestern Mediterranean Sea (NWMS), where it plays an important role in the functioning of marine ecosystems. Because of its sensitivity to atmospheric conditions, it is associated with a high interannual variability (Mertens and Schott, 1998), and may be strongly influenced by climate change (Somot et al., 2006). Part of the Western Mediterranean Deep Water (WMDW) formed by deep convection in the NWMS flows in the Atlantic Ocean through the Gibraltar Strait, and may affect the global thermohaline circulation through the impact of the Mediterranean Outflow Water on North Atlantic deep convection (Reid, 1979). Monitoring deep convection is therefore crucial, however direct in situ monitoring requires a huge investment and realistically can only provide limited temporal and spatial coverage. Our study is a first step toward monitoring deep convection from space: we investigate the feasibility of observing its variability using improved satellite altimetry. We analyse together a high-resolution oceanic numerical simulation of the Mediterranean circulation for the 1999–2007 period performed with OPAMED16 (Béranger et al., 2005), and sea level anomaly (SLA) satellite data provided b