Sabine Philipps (CLS, France); Michaël Ablain (CLS, France); Desjonqueres Jean-Damien (CNES, France)

Since Jason-2 has being launched (in 2008), it is currently used as the reference mission in the altimetry satellite constellation to generate multi-mission sea level products (e.g.: CMEMS/AVISO products). This is possible thanks to the very good performances of the sea level estimated by Jason-2. This concerns the long-term stability of Global Mean Sea Level (GMSL) evolution, as well as the smaller spatial and temporal scales for mesoscale applications. This highlights the importance to evaluate and monitor the altimeter mission performances.

The global assessment of Jason-2 measurements over ocean has been performed from the beginning of the mission in the framework of the CNES SALP (Système d'Altimétrie et Localisation Précise) project. The main objective of this activity is to provide an estimation of the mission performances over ocean. This consists in analyzing the Jason-2 data coverage as well as for missing measurements as for valid sea level measurements, in monitoring all altimeter and radiometer parameters, in estimating the sea level performances of delayed and real time products (GDR, IGDR, and OGDR/OSDR), and monitoring accurately the GMSL evolution.

In this paper, we have two separate objectives. The first one consists in giving a synthesis of the Jason-2 data performances over ocean. As the satellite is still working very well, a summary of the main diagnoses highlighting the very good performances of sea level is presented. They are mainly based on crossover analyses, comparisons with other missions and also in-situ measurements. The second objective is to describe improvements in the Jason-2 sea level processing in order to improve multi-mission sea-level products (e.g.: CMEMS/AVISO products). We will focus on the improvement of valid measurements selection in some specific areas (costal, high wave, rain cells), on the improvement of data quality on coastal areas, and on the improvement of the restitution of small scale oceanic feature. It is worth noting that these studies are of crucial importance better validate these missions recent altimetry missions launched this year (Jason-3 and Sentinel-3a) but also past missions (T/P, Jason-1, Envisat, etc…) .