Mesoscale and sub-mesoscale vertical exchanges from multi-platform experiments and supporting modeling simulations: anticipating SWOT launch (PRE-SWOT). Vertical motion associated with mesoscale and sub-mesoscale ocean features such as fronts, meanders, eddies and filaments plays a critical role in the exchanges of heat, fresh water and biogeochemical tracers between the surface and the ocean interior. Integrating our understanding of these processes to a climate scale, is one of the key challenges that faces Earth observation, limited by the high resolution of ocean data required to estimate the dynamic vertical transports and their correlation with horizontal heterogeneity. The forthcoming wide-swath satellite altimeter (SWOT) with a resolution one order of magnitude higher than previous instruments is the next big breakthrough in Earth observation. SWOT altimeter swaths will provide a perfect observational region around the Balearic Islands. Within PRE-SWOT, we anticipate the high resolution data that SWOT will provide, and lead the observations of vertical transports, associated with mesoscale and sub-mesoscale structures, that need to be collected. We propose a high-resolution multi-platform and multidisciplinary synoptic experiment. In situ systems, including gliders, drifters, CTD, ADCP, and water samples, will be coordinated with satellite data and modeling simulations to objectively determine physical and biochemical variability. The Spanish waters of the Western Mediterranean, have an unprecedented opportunity to provide an ideal ‘Pocket sized’ study region for quantification of the dynamic ocean interior exchange mechanisms, during the 60 days fast phase after launch in which the satellite will provide daily high resolution sea surface height measurements in selected areas of the global ocean. This is an opportunistic proving ground for SWOT capability, such that this project will provide SWOT readiness and a national capability for observing the major global ocean climates.
The members of this proposal have experience in the above-described activities. Both PIs of this project have participated in and/or lead several national and European funded projects as well as international initiatives where the problems addressed in this research have been identified, in journals such as “Nature”, as the next key elements to be solved in the coming years. More specifically, in the last 10 years their contributions provide the basis and approach for the present project: (1) studying mesoscale dynamics with satellite altimetry (2) estimating and analyzing vertical motion using Quasi-Geostrophic dynamics applied to in situ data, satellite data (3) exploring alternative mechanisms that can affect ocean ecosystems through combined multidisciplinary observations and modeling. Finally, the coordinator of this proposal is the only Spanish member of the present SWOT Science Team (SWOT-ST). PRE-SWOT brings expertise to the SWOT-ST, firstly in terms of experimental capacities for (sub) mesoscale multi-platform experiments and high resolution models, and secondly providing world class observational access to the region through Spanish infrastructure, including the fine tuning of regional in situ monitoring strategies, as essential preparatory activities needed before the launch of SWOT. The region described in this project is one of the Calibration/Validation and science sites, which will be targeted by in situ experiments during the fast sampling phase of SWOT. PRE-SWOT represents the unique opportunity for a leading Spanish contribution to the NASA-CNES SWOT mission.