New Level-3 and Level-4 near-real-time wave products derived from altimetry and SAR

Elodie Charles (CLS, France)

CoAuthors

Romain Husson (CLS, France); Nicolas Taburet (CLS, France); Alexis Mouche (IFREMER, France)

Event: 2018 Ocean Surface Topography Science Team Meeting

Session: Application development for Operations

Presentation type: Type Oral

A new near-real-time wave service started in July 2017 in the frame of the Copernicus Marine Environment Monitoring Service (CMEMS). It provides Level-3 along-track significant wave heights issued from different altimeters: Jason-3, Sentinel-3A, Saral/AltiKa and soon Cryosat-2.

This service is operated by CLS, relying on a Level-3 altimetry wave chain, adapted from the CMEMS/DUACS chain operated for sea level products. Upstream Level-2 wave data are processed to provide state-of-the-art calibrated wave products. First, only valid data are included, based on a rigorous editing combining quality flags and thresholds. Then, all the missions are homogenized with respect to a reference mission which is currently Jason-3. And finally, all the missions are calibrated on a network of in-situ buoy measurements.

Altimetry wave parameters are available on CMEMS catalog approximately 3 hours after the measurements. Wave dynamics happen on a short time-scale and this near-real-time constraint is therefore essential to allow an effective data assimilation for wave forecasting services. Besides, this service will soon provide data from four operational altimeters: the increased density of observations will not only improve model forecasts but also add resilience to the altimetry observing system.

This wave service is now expanding its scope to two new types of products: Level-4 gridded significant wave heights derived from altimetry and Level-3 spectral integral parameters derived from Synthetic Aperture Radar (SAR).

Level-4 gridded products will provide daily multi-mission maps of significant wave heights, ready-to-use to explore the short- to long-term variability of wave conditions or to identify interesting structures.

SAR Level-3 products will soon be available for the Sentinel-1A and 1B missions and will provide near-real-time wave height, period and direction at the peak of each identified wave partition. Unlike wave parameters derived from altimetry, SAR allows to work on different parts of the wave spectrum and therefore to distinguish swells generated remotely by different storms from waves generated by local wind. This new product will allow to investigate further wave dynamics, specific storm events and will provide more precise wave parameters to wave modelers, both for data assimilation and model validation purposes.

Besides feeding operational forecasting systems, this near-real-time wave service and its upcoming products can also be used for various applications: analysis of short- to long-term variability of wave conditions, statistics of extreme wave events, design of offshore and coastal structures, study of coastal morpho-dynamics, etc. To support the growing interest in quality observational wave products derived from satellites, this service will evolve with the satellite constellation and with technical developments. For example, the feasibility of a higher spatial resolution or a higher precision nearshore will be explored.
 

Oral presentation show times:

Room Start Date End Date
Lagoa Das 7 Cidades Fri, Sep 28 2018,09:45 Fri, Sep 28 2018,10:00
Elodie Charles
CLS
France
echarles@cls.fr