Advances in Altimetry Technologies in Marine Observation

Dear Colleagues,

Satellite radar altimetry is now the main way we keep an eye on how the sea and ocean surface changes over time, in terms of waves, ocean tides and currents, and changes in ice thickness. Thanks to a long series of measurements from various satellites, spanning over 30 years, it is possible not only to track the global mean sea level but also its rate of rise, acceleration and regional variability. New mission architectures, processing modes and alternative measurement techniques have increased the already high resolution and accuracy of data and improved the verification of the models obtained. These are particularly important for coastal altimetry.

The aim of this Special Issue is to present the current state of altimetry technology in oceanographic research against the background of its evolution.

The scope covers four topics: review articles on the history of missions and techniques; an overview and interconnection of key innovations such as SAR/Delay-Doppler, wide-swath, GNSS-R, new retrackers and atmospheric corrections with satellite altimetry; examples of the latest scientific applications, especially in the coastal zone, lakes, rivers and other water bodies; and prospects and directions for future research.

The development of altimetry began with the creation of a global ‘reference record’ of sea level and its trends thanks to the Jason/TOPEX–Poseidon mission and its continuation Jason-1/2/3. Subsequent missions such as CryoSat-2/Sentinel-3 enabled the introduction of Delay-Doppler/SAR modes, which improved resolution along the track and performance over coastal waters. Since 2020, the Sentinel-6 mission has enabled the continuation and precise calibration of the sea level record. The latest NASA and CNES satellite mission, SWOT (Surface Water and Ocean Topography), starting in 2023, aims at providing a new generation of water surface height measurements to create high-resolution 2D maps of ocean and inland water surface heights.

In 2024–2025, examples of the use of SWOT data to prove submesoscale structures (fronts/eddies) appeared in the literature; work is underway to integrate SWOT into multi-mission maps (L4); the possibilities of using Sentinel-3 (Hydro-Cryo) thematic products dedicated to hydrology, sea ice and land ice, as well as GPD+ tropospheric corrections for Sentinel-3 to reduce sea height errors, are being widely described, as are the use of retrackers and SAR mode in Sentinel-6/Jason-3 to reduce sea state-dependent errors for coastal areas and the use of GNSS-R (satellite and shore-based) data for sea height.

We are looking for articles pointing to the possibility of increasing the resolution of altimetry products; the possibility of direct observation of submesoscale dynamics, rivers and reservoirs; the reduction of wave-dependent errors and the improvement of inter-mission consistency; advanced atmospheric corrections (GPD+) and examples of use; GNSS-R/GNSS-IR data as a product supporting satellite altimetry; and the cross-calibration of products.

Dr. Kamil Kowalczyk
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Journal of Marine Science and Engineering is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• global and local sea level rise
• ocean currents
• mesoscale and submesoscale dynamics
• coastal ocean
• satellite hydrology
• altimetry retrackers
• tropospheric corrections (e.g., GPD+)
• radar interferometry (KaRIn)
• altimetry calibration and validation
• L2/L4 products (multimission analyses)