Ssalto/Duacs multimission processing

There are three key features in Duacs: homogeneous products built on heterogeneous data flows from all missions, data centers, agencies and product types; shortest delay based on robust software, operational hardware and 24/7 operators; highest quality based on altimetry and oceanography expertise and on strict quality control.

 

Data used

  •   GFO IGDR and GDR files, provided by Noaa.
  •   Jason-1 and Envisat IGDR and GDR files, delivered by the Ssalto/CMA data server.
  •   Topex/Poseidon GDR data, provided by Po.Daac.

Various Dynamic Auxiliary Data (DAD) are needed to process these altimetric data (ECMWF, TEC grids from JPL, NRT Mog2D corrections…)

Overview of the Ssalto/Duacs system

  • Data acquisition and homogeneisation, where most recent corrections, models and references recommended for altimeter products are applied.
  • Input data quality control. 
  • Multi-mission Cross-calibration, based on two different algorithms: a global multi-mission crossover minimization for orbit error reduction (OER), and Optimal Interpolation (OI) for long wavelength error (LWE).
  • Along-track Sea Level Anomaly (SLA) and Absolute Dynamic Topography (ADT) product generation for each mission.
  • Merging process: the mapping procedure is based the OI software used for LWE reduction, then used to merge data from all missions in a single map of SLA or ADT.
  • Quality Control.

See also the Ssalto/Duacs references