Periodic Reporting for period 2 - CEASELESS (Copernicus Evolution and Aplications with Sentinel Enhancements and Land Effluents for Shores and Seas)
Berichtszeitraum: 2017-11-01 bis 2019-10-31
a) New wealth of satellite data becoming available, with emphasis on the Sentinel family, covering a wider range of oceanographic and coastal processes than the present state-of-art
b) New (higher) resolution and prediction capabilities for met-ocean variables, for coupling and assimilation at unprecedented scales and leading to an improved error control and extrapolation potential
c) New coastal zone requirements (e.g. wind profiles for renewable energy) or applications (e.g. coastal water quality) that prompt demand for new CMEMS products
The potential of new CMEMS-based products, incorporating a wide range of coastal processes, assimilation and metrics has been the core of CEASELESS, with the following overall objectives:
- Recovery and application of new Sentinel data (S-1 winds, S-2 visible/infrared products related to water colour and bathymetry and S-3 altimetry) to derive a spatial structure for coastal metocean processes
- Assimilation strategies that better condition data in coastal areas, necessarily limited in space and therefore with limited “memory” for assimilation but presenting important gradients
- Application of met-ocean predictions for selected users in the four pilot sites considered: Danish coast, German Bight, Catalan coast and North Adriatic, demonstrating the new prediction capabilities and providing feedback to CMEMS for a coastal dimension
The developed high-resolution and coupled modelling suites (wind-waves-currents plus derived variables such as concentrations for water quality or incoming energy for risks) have been calibrated/validated using the new wealth of observations, assessing the performance of nested meshes, local parameterizations and the potential of unstructured grids to better capture coastline irregularities. This has allowed incorporating a new range of coastal processes (e.g. turbulence on surge propagation) and providing explicit error limits.
New Sentinel data, together with other satellite measurements (e.g. Jason-2, Jason-3, CryoSat-2, SARAL/AltiKa or Envisat) have been applied to determine spatial error patterns and dominant correlation structures. Here CEASELESS has explored the best strategies for reducing uncertainty as a function of weather conditions and domain geometry, based on the considered pilot cases. This has served to determine error dependence on coastal distance and prediction horizon. This has supported new coastal products that have been tested and interactively adapted to suit the practical requirements for a number of selected applications:
- Risk assessment in the North Sea (e.g. under the impact of Atlantic storms) and in the Mediterranean (e.g. under Medicanes for the North Adriatic).
- Offshore wind farm functional and resistant performance (e.g. wind or wave loads, supply operations, etc.) and including interactions (e.g. scouring in front of structures).
- Search and rescue applications considering how meteorological and oceanographic factors may affect trajectories, boat operations or safety.
- Water quality applications including aquaculture but also bathing water quality in areas conditioned by land discharges.
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.