The ocean tides are one of the major contributors to the energy dissipation in the Arctic Ocean. In particular, barotropic tides are very sensitive to friction processes, and thus to the presence of sea ice in the Polar regions. However, the interaction between the tides and the ice cover (both sea ice and grounded ice) is poorly known and still not well modelled, although the friction between the ice and the water due to the...

Recent sea surface height (SSH) trends in the South Pacific are substantially greater than trends in the North Pacific. Here, we use the Estimating the Climate and Circulation of the Ocean Version 4 Release 4 ocean state estimate and the Ocean Reanalysis System 5 to identify the forcing and mechanisms underlying that meridional asymmetry during 2005–2015. Thermosteric contributions dominate the spatial structure in Pacific SSH trends, but contributions from local surface heat fluxes are small....

The Japan Meteorological Agency (JMA) had been operating the Western North Pacific Ocean Data Assimilation System (MOVE/MRI.COM-WNP: hereafter referred to as the "old system") since March 2008 in order to monitor and forecast ocean conditions in the North Pacific Ocean and the seas around Japan. The old system consisted of the Western North Pacific Model (WNP: horizontal resolution of about 10 km) and the North Pacific Model (NP: horizontal resolution of about 50 km), and...

Ocean mesoscale eddies are the most energetic component of the ocean dynamics, important for the horizontal fluxes of energy, momentum, and tracers such as heat, carbon and nutrients. Today, observations of smaller scales are limited, and we might be missing 75% of the mesoscale eddies at high latitudes. The future SWOT SAR-interferometry wide-swath altimeter mission aims to provide 2D swath observations of ocean surface topography to characterize the ocean mesoscale and submesoscale circulation from the...

The first radar altimetry missions were dedicated to the open ocean. However, continental water surfaces (enclosed seas, lakes, rivers, flooding areas...) can also be measured by satellite altimetry. For many years now, satellite altimetry is increasingly used to monitor inland waters all over the globe, and even more with the advent of delay doppler radar altimeter embedded on the Copernicus Sentinel-3 and Sentinel6-MF missions, and the future SWOT mission based on interferometric radar imagery. For...

Satellite altimeters have continuously observed surface elevation changes across the Greenland Ice Sheet surface for the past three decades. Improvements made in processing these observations and in the development of new sensors during this time, have culminated in high resolution instruments, which are able to provide new insights into the physical processes and changes that the Greenland Ice Sheet experiences as the climate warms. Here, we compare elevation changes and trends in elevation change observed...

The SAR-mode processing in altimetry as it is currently operated in ground segments does not exploit the full capabilities of the SAR system in terms of spatial resolution. The so-called unfocused SAR altimeter (UFSAR) processing performs the coherent summation of pulses over a limited number of successive pulses (64-pulses bursts of a few milliseconds in length) reducing the along-track resolution down to 300 m only. Since recently [2], the concept of coherent summation has been...

The Copernicus Polar Ice and Snow Topography Altimeter(CRISTAL) mission, planned to be launched in 2027 will incorporate a dual Ku/Ka-band interferometric altimeter with specific transmission pulse sequences designed to enhance the performances over sea and land ice. The open burst mode will enable the generation of Fully Focussed products over sea ice with snow depth retrievals derived from the Ku/Ka range differences instead of taking them from external auxiliary data. In the same way, as...

The Copernicus Sentinel-3 Surface Topography Mission (STM) provides extremely valuable surface elevation information over inland waters, sea ice and land ice, thanks to its SAR altimeter which retrieves high-resolution along-track elevation measurements, and to its orbit that covers high-latitude polar regions. To ensure that these measurements can be used with confidence, and to maximize the return on investment of the Copernicus Sentinel-3 STM, adequate validation of the geophysical retrieval methods, processing algorithms and corrections must...

The main goal of the IMHOTEP OST-ST project is to investigate the response of the global ocean to fully-varying freshwater discharges from rivers and from the Greenland ice sheet between 1980 and 2018. This response concerns sea surface salinity (SSS), regional sea surface height (SSH) and its manometric/steric components, heat and freshwater contents, water mass properties, regional to basin-scale circulation, etc. We are currently analyzing satellite/in-situ observations and the outputs from a recent series of...

DORIS (Doppler Orbitography and Radio positioning Integrated by Satellite) is a space based piggyback satellite system which when used as terrestrial measurement system can provide an accuracy of 10cm in absolute position measurement and in the order of sub- cm accuracy in relative measurements. When it rides piggy back on any satellite system can provide an orbital accuracy up to cm level. This space based geodetic measurement technique has been used for the past three...

The determination of time-variable gravity field from DORIS is typically restricted to the very first degrees of the spherical harmonic spectrum. In order to better attribute the orbit perturbations to spatially localized mass redistributions, we apply in this contribution a novel parametrization by representing the mass changes by a limited number of spatial patterns which were identified in a previous step by a principal component analysis applied to the gravity field time series from GRACE...

The conflict between Russia and Ukraine has impacts on the DORIS network. Badary's DORIS beacon is turned off at Russia's request, creating a hole in DORIS coverage. To compensate for this loss, CNES and IGN are considering deploying beacons on other sites in the region, requiring agreements to be put in place and work to be carried out, which can take time. An increase of the jamming on the DORIS signals in Eastern Europe is...

The ground tracking network has a dual objective: serving ocean altimetry and geodesy. We look back over the continual enhancement of the infrastructure to better achieve these goals. We highlight the contribution of the network for the POD in terms of reliability and performance, and for the geodesy thanks to long-term life, stability and co-location of the stations. We make a status report on the current overall performance of the sixty ground stations evenly distributed...

Launched on 21 November 2020, Sentinel-6 Michael Freilich is a Copernicus satellite designed to ensure the continuity to the mean sea level climate time series measured by the TOPEX/Poseidon and Jason satellites since 1992. The main payload carried on-board Sentinel-6 is the Poseidon-4 (POS4) dual frequency radar altimeter. POS4 uses an approximate9 kHz Pulse Repetition Frequency, and an innovative interleaved chronogram allowing for the optimization of the number of measurements acquired. Thanks to the interleaved...

The recent launch of Sentinel-6 Michael Freilich offers the possibility of continuing global mean sea level (GMSL) monitoring well into the current decade. In this presentation we report Sentinel-6/Jason-3 inter-mission bias estimates based on direct sea surface height (SSH) collinear differences of near coincident measurements during the verification phase, and with comparisons to a global network of tide gauges. In an effort to provide a more consistent SSH time series and seamless transition to Sentinel-6,...

A new estimation method for the mean sea surface dynamic height (MSDH) is applied for a variational ocean data assimilation system developed in the Meteorological Research Institute, Japan Meteorological Agency (MOVE system). MOVE system constrains temperature and salinity as state variables (Fujii and Kamachi, 2003) with assimilating in-situ profiles, sea surface temperature, and sea level anomalies (SLAs). For the calculation of the cost function associated with the SLAs, a MSDH is necessary to refer to...

The improvement of retracking algorithms aiming at the optimal and efficient estimation of the geophysical parameters is a core activity within the altimetry community. The importance of having an optimal, robust and efficient retracking solution is indeed more and more critical with the increase of the amount of data and the high demanding requirements in terms of data quality and resolution. The accuracy of the retracking solution in retrieving the geophysical parameters has a strong...

Since October 2016, and in the framework of Copernicus Marine Service, Mercator Ocean International delivers in real-time daily services (weekly analyses and daily 10-day forecasts) with a global 1/12° high resolution (eddy-resolving) system (Lellouche et al., 2018). Oceanic observations are assimilated in the model using a reduced-order Kalman filter method. Along track altimeter Sea Level Anomaly (SLA), satellite sea surface temperature (SST) and sea ice concentration, and in situ temperature and salinity vertical profiles are...

Statistical methods are usually used to provide estimations of the wet tropospheric correction (WTC), necessary to correct altimetry measurements for atmospheric path delays, using brightness temperatures measured at two or three low frequencies from a passive microwave radiometer on board the altimeter mission. Despite their overall accuracy over oceanic surfaces, uncertainties still remain in specific regions of complex atmospheric stratification. Thus, there is still a need to improve the methods currently used by taking into...

Sentinel-3 is an Earth observation satellite series developed by the European Space Agency as part of the Copernicus Programme. It currently consists of 2 satellites: Sentinel-3A and Sentinel-3B, launched respectively on 16 February 2016 and 25 April 2018. Among the on-board instruments, the satellites carry a radar altimeter to provide operational topography measurements of the Earth’s surface. Over sea-ice, the main objective of the Sentinel-3 constellation is to provide accurate measurements of the sea-ice sea...

River discharge monitoring is crucial for many activities ranging from the management of water resources to flood risk mitigation. Due to the limitations of the in situ stations (e.g., low station density, incomplete temporal coverage as well as delays in data access), the river discharge is not always continuously monitored in time and in space. This prompted researchers and space agencies, among others, in developing new methods based on satellite observations for the river discharge...

Topological tools from nonlinear dynamics are used to assess enduring near-surface Lagrangian aspects of the Malvinas Current. The procedure, known as BraMAH (Branched Manifold Analysis through Homologies) is a finite-dimensional and finite-time technique that enables distinguishing and classifying the different nonlinear processes at work in time series datasets (Charó et al, 2021, 2020, 2019, Sciamarella & Mindlin, 2001, 1999). Consistent results are obtained comparing datasets generated with simplified models proposed to understand chaotic advection in...

The scope of this presentation is to provide an update on the ESA radar altimetry services portfolio for the exploitation of CryoSat-2 (CS-2) and Sentinel-3 (S-3) data from L1A (FBR) data products up to SAR/SARin L2 geophysical data products. At present, the following on-line & on-demand services compose the portfolio: - The ESA-ESRIN SARvatore (SAR Versatile Altimetric TOolkit for Research & Exploitation) for CS-2 and S-3 services. These processor prototypes allow the users to customize...

Although CFOSAT is dedicated to wind and wave characterization the Ku altimeter on board has the capacity of providing and Sea level measurements, relevant to enrich the DUACS (Data Unification and Altimeter Combination System) Sea Level Anomaly products for the benefit of the Copernicus Marine Service users. With an orbit reaching 82° latitude, it could in particular help to compensate the loss of current nadir missions at low and high latitudes. The short and long...