Abstract's details

New advances in altimetry towards the coast : example of the CTOH sea level products

Fabien Léger (LEGOS / CTOH, France)


Florence Birol (LEGOS / CTOH, France); Fernando Niño (LEGOS / CTOH, France); Wassim Fkaier (LEGOS / CTOH, France); Fabien Blarel (LEGOS / CTOH, France)

Event: 2022 Ocean Surface Topography Science Team Meeting

Session: Coastal Altimetry

Presentation type: Type Poster

Contribution: PDF file


Through different projects, the Center for Topographic studies for the Ocean and Hydrosphere (CTOH) contributes largely to advances in coastal altimetry and to its use in coastal applications. It has developed the X-TRACK software dedicated to the reprocessing of coastal altimetry data. X-TRACK is now a mature sea level product distributed worldwide by AVISO+ (https://www.aviso.altimetry.fr), cited in many scientific publications. It consists in long time-series of SLA from most altimetry missions, processed homogeneously, but also as long-track empirical tidal constants. The latter provides independent synoptic data on the coastal ocean for tidal studies, validation of tidal models or assimilation into tidal models.

In order to continue provide the most complete sea level datasets to coastal users, the CNES L2P Product (https://www.aviso.altimetry.fr/en/data/products/sea-surface-height-products/global/along-track-sea-level-anomalies-l2p.html) will now be integrated into the X-TRACK processing chain: 12 altimetry missions, covering the 1992-2021 time period.

The CTOH contributes also, trought the high performance of X-TRACK software, to the development of new coastal sea level products specifically designed for climate studies, in close collaboration with ESA, TUM, CLS, NOC and SKYMAT. As part of the ESA Climate Change Initiative project, the Adaptive Leading Edge Subwaveform (ALES) Retracker (Passaro et al., 2014) and the X-TRACK software (Birol et al., 2017), previously validated and successfully applied to coastal sea level research, have been combined for the first time, in order to reprocess 18 years of sea level anomaly data (Jan. 2002 to Jan 2020) at a high frequency level (20 Hz) based on Jason missions. This new coastal sea level product called X-TRACK/ALES (https://climate.esa.int/en/projects/sea-level/data/) significantly extends the spatial coverage of sea level altimetry data in the coastal direction, now reaching a distance of 1.2-4 km from the coast on average (Birol et al., 2021). This is an unprecedented coastal coverage for any long-term altimetry data set, and then a significant contribution to the coastal research community. In addition, a new network of virtual altimetry-based stations in coastal areas of the world has also been derived from this dataset, providing new information on sea level change in the world coastal zones (see Cazenave et al., OSTST 2022).

Poster show times:

Room Start Date End Date
Mezzanine Tue, Nov 01 2022,17:15 Tue, Nov 01 2022,18:15
Mezzanine Thu, Nov 03 2022,14:00 Thu, Nov 03 2022,15:45
Fabien Léger