SSALTO/DUACS, 15 years of precise and consistent multi-mission altimetry data
Gerald Dibarboure(1) , Joel Dorandeu(1) , and Nicolas Picot(2)
8-10, rue Hermès,
31520 Ramonville Saint-Agne,
(2) CNES, 18 Avenue Edouard Belin, 31401 Toulouse, France
- Delayed Time Products: A consistent data set from built upon all altimeters:
DUACS is part of the CNES SSALTO multi-mission ground segment. It processes data from all altimeter missions: Jason-1, T/P, ENVISAT, GFO, ERS1/2 and GEOSAT. In 2005 the SSALTO/DUACS system has performed a complete re-analysis of all altimeter data with the state-of-the-art corrections, models and references recommended for the new generation of Jason/ENVISAT GDRs, as well as the best Cal/Val and intercalibration algorithms. It is the first time in altimetry history that a homogeneous and consistent merging of all missions is carried out.
This second generation of DUACS products is composed of global data sets of along track and gridded Sea Level Anomaly, Absolute Dynamic Topography (see Fig. 1), and geostrophic currents, but also of new regional-specific products. The system uses common processing facilities for global and regional applications. It ensures that upgrades are consistently applied on all products to better serve the altimetry user community.
- Near Real Time Activities:
Twice per week, DUACS provides GODAE and climate forecasting centers with directly useable, high quality Near Real Time (NRT) altimeter data. Regional products are delivered on a daily basis to operational projects such as MFSTEP or MERSEA.
NRT altimeter data from SSALTO/DUACS are distributed by AVISO on FTP, Web and through a Live Access Server. The DUACS system also provides a long term monitoring of NRT data it has used, to quickly detect anomalies, drifts and discontinuities in incoming altimeter data. Quality assessment reports are released twice per week.
- Upgrades in 2006:
The ongoing effort to improve the quality of DUACS combined data, and the robustness of the NRT system will be maintained with the analysis and the operational use of opportunistic Cryosat data on ocean, the computation of better global and regional mean profiles (fully compatible with the respective processing), and preliminary studies to take into account real time altimeter data (fast delivery ~ a few hours) into the NRT system.