The CEASELESS project has contributed to a quantum leap for understanding and predicting coastal oceanographic processes and a variety of applications, based on recent developments in satellite/in-situ data, high-resolution models and novel assimilation approaches for anisotropic coastal domains. The main advances beyond the state of the art can be highlighted by the following elements:
1. Recovery algorithms for coastal areas where, making use of the difference between leading/trailing wave-forms of altimetric echoes, to reinterpret a previously discarded set of data
2. Assessing the actual value of assimilation for coastal domains, combining the spatial structure of satellite data with the temporal variation of in-situ records, showing how such data merging can be used for bounding errors.
3. New parameterizations for the air-sea interface that, incorporating the actual turbulence production/dissipation can lead to physically improved closures for near surface turbulence and the parameterization of wind drag effects. In parallel, assessing the seabed boundary condition for shallow water applications.
4. Quantitative assessment of topo-bathymetric effects in conditioning wind fields and the resulting wave/current predictions. There result sharp gradients that modulate error estimations and reliability of coastal decisions (e.g. preferred locations for renewable energy, aquaculture farms, etc.).
5. The role of the 3D land discharges (rivers and distributed runoff) in the selected pilot sites, considering water but also sediments and nutrients, showing how the land boundary condition can play an important role in coastal oceanography. From here, determining the role of the coastal zone as an active boundary layer for shelf dynamics.
CEASELESS results for coastal downscaling and derived products have proved the potential of a CMEMS extension towards the coast. This refers to a domain extension but also to the incorporation of new applications, such as public harbour and coastal authorities, private stakeholders, such as aquaculture exploitations, port operators or renewable energy companies such as Vattenfall. These transfer activities demonstrate the actual benefit of CMEMS-based predictions with explicit error limits and at higher resolution/accuracy for a wider set of coastal applications that can be summarized by:
a) Risk assessment linked to erosion and flooding impacts for selected pilot sites (German Bight, Catalan coast and North Adriatic).
b) Renewable energy operation, safety and maintenance for selected pilot sites (mainly for the Horns Rev Area in the Danish coast regarding safety and operation of the structures)
c) Water quality and associated exploitation for tourism and aquaculture for selected pilot sites (mainly for the Danish coast and Catalan coast).
These applications prove the potential of a CMEMS coastal extension, demonstrating the role of coastal processes and the importance of combining in-situ data with satellite measurements for restricted coastal domains. It is in these areas, close to the land-sea border, where gradients and duration limits increase the overall error with respect to open sea oceanography. CEASELESS has contributed to partially overcome such a loss of reliability for coastal products by improving shallow water parameterisations, adding new coastal processes, incorporating the land discharge and applying anisotropic error metrics. These advances have been supported by higher resolution and improved recovery algorithms for satellite data, unstructured grid modelling suites and coastal assimilation strategies. The range of applications and stakeholders considered underpin the pressing requirements to advance coastal downscaling and derived products based on CMEMS, in support of a CMEMS coastal extension.
