Types of dataset: Ssalto/Duacs multimission altimeter products.
Contents: multimission gridded sea surface heights computed with respect to a seven-year mean
Use: Ssalto/Duacs gridded products are devoted to scientific applications and non-commercial use: study of ocean variability (mesoscale circulation, seasonal variation, El Niño...), including operational oceanography (near-real time products).
Condition of access : All Ssalto/Duacs product users need an account, see Access to Ssalto/Duacs data
Data access service: see Data access service. In NRT, FTP delivers the most recent data (day-0) whereas Opendap/geographic-temporal extraction tool/LAS only delivers data more than one month.
Description: gridded product, provided in near-real time and in delayed time. As a snapshot, each map represents the sea state for a given day. Two levels of resolution are available: high resolution (1/3°x1/3°, Mercator grid) or low resolution (1°x1°, Mercator grid). Mercator gridded product is also provided in a second version that is resampled on a 1/4°x1/4° cartesian grid (really destinated to users confused by the Mercator grid). 
A formal mapping error file is also available, with geostrophic velocity anomalies.
Geographic coverage: global
A specific regional product with an improved quality is available in local areas (more information).

Format: NetCDF

Tools:

• User Handook: Ssalto/Duacs User Handbook : (M)SLA and (M)ADT Near-Real Time and Delayed Time Products
• Data reading software

Description: this delayed time product is available in two versions:

• "Ref" (Reference) series: homogeneous datasets based on two satellites (Jason-2 / Envisat  or Jason-1 / Envisat or Topex/Poseidon / ERS) 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 (Jason-2 / Jason-1 / Envisat from 2009 or between October 2002 and September 2005, the association Jason-1 / Topex/Poseidon / Envisat / GFO). Sampling and Long Wavelength Errors determination are improved, but quality of the series is not homogeneous.

Copyright : 2005 - ongoing CLS - Cnes

DT-MSLA "Ref"

DT-MSLA "Upd"

DT-MSLA Geosat

Tools:

• Readme for Maps of Sea Level Anomalies from Geosat
• Noaa website : Geosat JGM-3 GDRs

Description : the NRT data are delivered daily with a 6-day delay, a 3-day delay and a 0-day delay.
Data period : within a few months at most, from the latest update of the DT products to today.
Copyright : 2001-ongoing CLS-Cnes.

High resolution

Low resolution (1°x1°)