SSALTO/DUACS Multimission Altimeter Products

Homogeneous Global Processing (Ref): Monthly Maps of Sea Level Anomaly (DT-MSLA)

Duacs is the Ssalto multimission altimeter data processing system. It processes data from all altimeter missions (Jason-1&2, T/P, Envisat, GFO, ERS-1 & 2 and even Geosat) to provide a consistent and homogeneous catalogue of products for varied applications, both for near real time applications and offline studies. The Delayed Time (DT) component of SSALTO/DUACS system is responsible for the production of processed Jason-1, Jason-2, T/P, Envisat, GFO, ERS1/2 and even Geosat data in order to provide a homogeneous, inter-calibrated and highly accurate long time series of SLA and MSLA altimeter data. DT component is made of two processing series:

• Upd (for "Updated"): this is an up-to-date series using up to 4 satellites at a given time (taking into consideration T/P on its new orbit and GFO), using all missions available. Thus it has the best possible sampling. Upd series is better in quality but not homogeneous over the time period, because it is based on the best sampling available in time.

• Ref (for "Reference"): this set is based on only two missions at most: T/P and ERS followed by Jason-1 and Envisat or OSTM/Jason-2 and Envisat respectively, on the same two orbits. Thus it is homogeneous all along the available time period. thanks to a stable sampling, but might not be the best in quality at a given time. The use of the Ref series is mainly for application in need of great stability (but it must be kept in mind that the data might not be of the best possible quality).

The difference between these two processing series is thus the number of missions as key input of Optimal Interpola- tion (OI) Software for LWE (2.3.5.). This system finally delivers Delayed Time processed SLA and MSLA combining fully processed data from various altimetric missions (Topex/Poseidon, ERS-1/2, Jason-1, Envisat and OSTM/Jason-2) such as:

• High resolution Maps of Sea Level Anomaly (DT-MSLA) combining all satellites
• High resolution Maps of Absolute Dynamic Topography (DT-MADT), merging all satellites
• High resolution maps of geostrophic velocities anomalies derived from maps of Sea Level Anomaly combining all satellites
• High resolution maps of absolute geostrophic velocities derived from maps of Absolute Dynamic Topography combining all satellites

Sea Level Anomaly (cm)
Zonal Global by 1/3 deg, Mercator Grid
Meridional82S to 82N by 1/3 deg, Mercator Grid
TemporalDec 1992 to Mar 2010 by 1 month(s)
Static? yes
Volume3.8MB per variable per month
AcquiredMar 14, 2011
APDRC contact
SupplementsSSALTO/DUACS User Handbook