Abstract's details

New CNES-CLS Mean Dynamic Topography of the global ocean from altimetry, gravity and in-situ data

Marie-Hélène Rio (CLS, France)


Sandrine Mulet (CLS, France); Nicolas Picot (CNES, France); Gérald Dibarboure (CNES, France)

Event: 2018 Ocean Surface Topography Science Team Meeting

Session: The Geoid, Mean Sea Surfaces and Mean Dynamic Topography

Presentation type: Type Oral

Contribution: PDF file


The Mean Dynamic Topography (MDT) is a key reference surface for altimetry. It is needed for the calculation of the ocean absolute dynamic topography, and under the geostrophic approximation, the estimation of surface currents. Those are required for a wide range of applications as the management of fishery resources, the monitoring of potential pollution, maritime security… Also, the MDT is the missing component for the optimal assimilation of altimeter data into operational ocean system as those run under the Copernicus Marine Environment Monitoring Services (CMEMS).
CNES-CLS Mean Dynamic Topography solutions are calculated by merging information from altimeter data, GRACE and GOCE gravity data and oceanographic in-situ measurements (drifting buoy velocities, hydrological profiles). Objective of this communication is to present the newly updated CNES-CLS18 MDT. The main improvements compared to the previous CNES-CLS13 solution is the use of updated input datasets: the GOCO05S geoid model (instead of DIR4) is used together with all drifting buoy velocities (SVP-type and Argo floats) and hydrological profiles (CORA database) available from 1993 to 2017 (instead of 1993-2012). The new solution also benefits from improved data processing (in particular a new Ekman model is used to extract the geostrophic component from the buoy velocities) and methodology (in particular the correlation scales used for the multivariate mapping have been revised). An evaluation of the new solution compared to the previous version and to other existing MDT is done through comparison to independent in-situ data.

Oral presentation show times:

Room Start Date End Date
Lagoa Do Congro Fri, Sep 28 2018,10:00 Fri, Sep 28 2018,10:15
Marie-Hélène Rio