High-Resolution SWOT Simulations of the Macrotidal Seine Estuary in Different Hydrodynamic Conditions

The goal of the Surface Water and Ocean Topography (SWOT) mission, a future wide-swath radar altimeter, is to measure the elevations of ocean and continental water surfaces with unprecedented precision. A simulator of SWOT high-rate (HR) interferometric SAR images has been developed to provide SWOT-like data to scientists and as a tool to develop and test HR ground processing algorithms. In this letter, we evaluate the errors of the extracted water levels in different hydrodynamic and topographic contexts in the Seine estuary based on simulated SWOT HR data. The results confirm height errors generally below 10 cm after km-scale averaging for the majority of the observations. Higher errors mostly occur in areas where the surrounding topography causes layover. This letter also reveals the interactions between tide and streamflow and their impact on the spatial variability of the water levels in the estuary.