COSMO

Monitoring of COastal hydrodynamics by combining Spatial observations and numerical MOdeling : the COSMO project

Coastal zones, including deltas and estuaries, are considered the most vulnerable environments to the effects of anthropogenic impact and climate change (CC), and are defined as multi-hazard and multi-risk zones (coastline retreat, storm surge flooding, coastal river flooding and sea-level rise, pollution). The time evolution of these systems and their hydro-morphodynamics response of these systems to climate drivers is very complex. Indeed, they are continuously changing in space and time, due to the non-linear interactions between various processes such as tides, swells, storms, sea-level rise in the context of CC and river flows as well. Moreover, the LR products will be also explored to investigate the extent of their applications for nearshore systems. With the aim to enhance the monitoring of coastal processes, the changes of these systems reproduce their multi- timescale evolution, combining different approaches by the use of different sensors (airborne and spaceborne), including in-situ measurements, and numerical tools are strongly required and crucial for further projections.

The new mission SWOT provides us with a high resolution required for an excellent coverage that improves the monitoring of physical processes and the modeling of the hydro-morphodynamics evolution of coastal systems in response to water level changes; which represents a significant advance for coastal oceanography and estuarine hydrology.

As part of the SWOT Science Team and CNES TOSCA and NASA ROSES programs, a series of four projects have already been carried out with a special focus on the use of SWOT in coastal and estuarine areas. The outcomes of these projects have provided us with important insights into the use of SWOT in these environments. With the launch of SWOT and the acquisition of data (water level, wave height, DEM, water slope…), we will be able to give answers to different applications by investigating the accurate contribution of SWOT in these environments and the various challenges raised by the Science team SWOT in recentyears. In-situ observations from other field campaigns such as opendata acquired for the S-MODE will also be helpful to compare or to corroborate our observations, especially with respect to airborne campaigns.

This context introduces the main challenges of this PhD project aiming to investigate the coastal hydrodynamics induced by sea level, storm surges and waves in response to weather drivers in the case of Normandy coasts. A special focus will be given to extreme events for assessing flood hazards, especially in areas connected to fluvial discharge as Seine bay. This objective will be fulfilled by developing new approaches based on the combination of remote sensing observations and numerical modeling to improve our monitoring of coastal and nearshore processes in Normandy (NW France).

The main challenges addressed are:

  1. To which extent SWOT products could improve the monitoring of hydrodynamic processes (waves, storm surges) in nearshore and coastal environments?
  2. What is the contribution of SWOT’s data assimilation to improving numerical models/simulations of coastal hydrodynamics?
  3. How can we optimize the use of SWOT products to investigate coastal flooding hazards?

Detailed Objectives

To address these challenges, the project is structured in three parts:

1. Spatial observations of hydrodynamics (water level, waves) by the new mission SWOT and the conventional satellites (Sentinel 3, 6, ..)

2. Numerical modeling and data assimilation (DA) for reducing uncertainties

3. Evaluation of the benefits of using SWOT products and Data Assimilation for assessing coastal flood hazards/compound flood hazards.

Direction: Em. Imen Turki (imen.turki@univ-rouen.fr)

Co-supervision: Laurent Froideval

CNES Involvement: Nicolas Picot , Alejandro Bohe, Aurelien Carbonière

Programs Supporting COSMO: EONES-SWOT (E. I. Turki) and SWOT4COST (E.I. Turki and B. Laignel)