MADT - Maps of Absolute Dynamic Topography and Absolute Geostrophic VelocitiesEntry ID: AVISO_MADT
Abstract: Contents: gridded sea surface heights above geoid; dynamic topography is the
sum of sea level anomaly (SLA) and mean dynamic topography (MDT, Rio05 here)
Use: study of the general circulation (ocean gyres ...)
Global gridded data (1/3°x1/3° on a Mercator grid), available in near-real time
and in delayed time in NetCDF format.
In delayed time, two types of products are available:
- "Ref" ... (Reference) series: homogeneous datasets based on two satellites
(Topex/Poseidon, Jason-1 + ERS, Envisat) with the same groundtrack. Sampling is
stable in time.
- "Upd" (Updated) series: up-to-date datasets with up to four satellites at a
given time (adding GFO and/or Topex/Poseidon on its new orbit). Sampling and
Long Wavelength Errors determination are improved, but quality of the series is
Absolute geostrophic velocities are also available for gridded merged data.
Regional products with an improved quality are available in local areas
Start Date: 2001-08-01
Quality See data processing information at
Access Constraints Access to Ssalto/Duacs products
Ssalto/Duacs products use Jason-1, Envisat, GFO, ERS-1, ERS-2 and
Topex/Poseidon data. File format is NetCDF, but the system also delivers images
in Postscript format (only for gridded products).
Ssalto/Duacs system delivers global and specific regional products; combined
datasets are also provided for high precision ... altimetry.
Near-Real Time products cover the 2001/08/22 - 2006/11/14 period. Delayed time
data are available from October 1992.
Condition of access
Ssalto/Duacs NRTNear Real Time data are available via FTP:
- with user identification and password for data <1 month , for scientific
applications (GodaeGlobal Ocean Data Assimilation Experiment, seasonal/climate
prediction centers) provided that a data use agreement is signed with Cnes.
- or freely available for data older than one month (i.e NRT and DT data> 1
CLS remains in charge of the commercial applications of these near-real time
For both DT and NRT products, the above acknowledgement has to be cited: "The
altimeter products were produced by Ssalto/Duacs and distributed by Aviso with
support from Cnes".
See http://www.aviso.oceanobs.com/html/donnees/duacs/access_uk.html for
Use Constraints When using Ssalto/Duacs data (NRT or DT-(M)SLA and (M)ADT), please cite: "The
altimeter products were produced by Ssalto/Duacs and distributed by Aviso, with
support from Cnes".
See http://www.aviso.oceanobs.com/html/donnees/tools/citations_uk.html for
Data Set Progress
Distribution Media: FTP
Distribution Format: NetCDF
Phone: (+33) 561-394-768
Fax: (+33) 561-751-014
Email: aviso at cls.fr
CLS - Space Oceanography Division 8-10 rue Hermes Parc Technologique du Canal
City: Ramonville-St Agne
Postal Code: 31526
Creation and Review Dates
DIF Creation Date: 2004-04-13
Last DIF Revision Date: 2006-11-20