The SWOT satellite in the estuaries and coastal zones
Abstract
The coastal and estuarine environments are among the most affected by human impact and climate change and the most vulnerable regions: inondations, shoreline retreat, pollutions… The hydrodynamic monitoring is essential for a good management of these environments, but it is difficult because: hydrodynamic is complex with many hydro-meteo-ocean phenomena; tide gauges for the hydrodynamic monitoring are sparsed; conventional altimeters have difficulties to observe the coastal physical processes at small scale.
The future SWOT altimeter (Surface Water and Ocean Topography; NASA, CNES, CSA, UKSA mission; launch in 2021), with its high spatial resolution and excellent global coverage, will improve our knowledge on the complexity of the physical processes in the coastal systems. Our work focuses on the ability of SWOT to reproduce the spatial and temporal variability of the hydrodynamic, resolution and products needed to understand the hydrodynamic, tidal signals in estuaries. We use two approachs applied in differents environments (The Channel, Atlantic, Mediteranean and Gulf of Mexico coasts and estuaries): comparison of in situ and simulated SWOT data from signal processing methods; combining of hydrodynamic modeling (T-UGOm, DELFT-3D) and SWOT simulator. The results show a best reproduction of the hydrodynamic by SWOT in microtidal than macrotidal contexts, a decrease of the reproduction from upstream to downstream estuary, an aliasing problem, observation of some storm surges and floods. The combining of modeling and SWOT simulator show a good restitution of the spatial variability of the water level along the estuary. There are several problems in the SWOT simulation near the shoreline: layover and different roughnesses on the shore. In the estuaries, the river products seem rather well adapted. In the offshore, the LR products are adapted. In the nearshore, the best compromise between the spatial resolution and vertical precision to observe the hydrodynamic processes is 250 m. In the shore, the HR and raster products should be the most suitable. In the estuaries, extracting the tidal signals from observed or modeled time series is not trivial, because the tidal signal is not stationary and is asymetric and the minimum length of the SWOT time series needed to separate the tidal components is quite large: 3 years.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS52B..01L
- Keywords:
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- 1845 Limnology;
- HYDROLOGYDE: 1856 River channels;
- HYDROLOGYDE: 4520 Eddies and mesoscale processes;
- OCEANOGRAPHY: PHYSICALDE: 4544 Internal and inertial waves;
- OCEANOGRAPHY: PHYSICAL