Refining the Resolution of DUACS Along-Track Level-3 Sea Level Altimetry Products

This paper describes the demonstration of a regional high-resolution level-3 (L3) altimeter data unification and combination system (DUACS) developed with support from French space agency (CNES). Deduced full-rate (20 Hz to 40 Hz) level-2 (L2) measurements, this product provides sea level anomalies (SLA) other essential physical variables at spatial resolution one sample every ~1 km over North Atlantic Ocean. allows us resolve wavelengths ~35 ~55 depending on considered. was made possible by recent advances in radar processing for both synthetic aperture (SAR) low-resolution-mode (LRM) as well improvements different stages DUACS chain. Firstly, new adaptive low-resolution range migration correction (LR-RMC) techniques were considered Jason Sentinel-3 (S3A), respectively. They significantly reduce errors short wavelengths, also reduces land contamination near coast. Next, up-to-date geophysical environmental corrections selected production. includes specific intended measurement noise LRM measurements thus enhance observability wavelengths. Compared 1 product, observable reached are reduced up third, or half northeast region. The residual noises optimally filtered taking into consideration observing capabilities altimeters processed. A recovery strategy applied, optimizing availability, coastal open ocean areas. L3 is better resolved than conventional especially coast, where it defined ~5 against ~10 version. Multi-mission cross-calibration optimized an improved long-wavelength error (LWE) correction, leading consistency between tracks, 9–15% reduction SLA variance cross-overs. improves overall tide gauge differences 5 17% compared S3A Jason-3 (J3) Primarily applications, can contribute improving numerical model output via assimilation. It opens perspectives understanding sea-surface dynamics, representation currents refined spectral content revealing unbalanced signal.