Toward Higher resolution Level3 altimeter products for Assimilation Systems

Marie Isabelle Pujol (CLS, France)


Yannice Faugère (CLS, France); Mounir Benkiran (MOI, France); Oscar Vergara (CLS, France); Gérald Dibarboure (CNES, France)

Event: 2019 Ocean Surface Topography Science Team Meeting

Session: Application development for Operations

Presentation type: Type Oral

In 1998, first Level3 along-track, user friendly altimeter products have been developed with support from CNES and delivered to the users on AVISO+. The Level3 processing includes a homogenisation of the SLA for the different altimeters (i.e. reduction of the global and regional biases), allowing the users to directly use the products without any pre-processing. They are widely used for different applications, including assimilation in numerical models. Since 2008, such products are generated and disseminated by the Copernicus Marine Service (CMEMS; previously MyOcean during its demonstration phase). They allow the user to change the physical content of the altimeter measurement in consistency with the model capabilities and characteristics, thus considerably improving the results of the assimilation of the altimeter measurement into the models.
With the future altimeter missions as the large swath SWOT mission, the altimeter processing will face a new challenge: be able to accurately process the signal at finer spatial scales. On the other hand, users and more particularly modelers need to make their system ready for assimilation and propagation of the finer scale structures observed. With that objective, a new generation of along-track products is under development with support from CNES. They are derived from high resolution (20Hz) altimeter measurement and are specifically processed in order to solve finer scales up to ~30 km. Recent development enabled to optimize the Sentinel3 SAR altimeter processing (Boy 2017, Moreau,2018) and the Jason/Altika noise level (Zaron 2016, Tran 2019) and allow us to better exploit the fine-scale content of the altimetric missions. Experimental datasets, with a nearly 1km (5Hz) sampling, are already available on AVISO+ ( and can be tested by users.
Operational and experimental altimeter products and their impact for numerical models will be presented.


Oral presentation show times:

Room Start Date End Date
The Monroe Hub Wed, Oct 23 2019,09:45 Wed, Oct 23 2019,10:00
Marie Isabelle Pujol