Preprints
https://doi.org/10.5194/egusphere-2024-1323
https://doi.org/10.5194/egusphere-2024-1323
10 Jun 2024
 | 10 Jun 2024
Status: this preprint is open for discussion.

A facet based numerical model to retrieve ice sheet topography from Sentinel-3 altimetry

Jérémie Aublanc, François Boy, Franck Borde, and Pierre Féménias

Abstract. In this study, we present a facet-based numerical model dedicated to ice sheet radar altimetry. The model simulates Sentinel-3 UnFocused-Synthetic Aperture Radar (UF-SAR) waveforms, by calculating the backscattered radar signal over the 10 m facets of the Reference Elevation Model of Antarctica (REMA). The simulation is exploited to determine the coordinates of the impact point on-ground, where the surface elevation is estimated. The complete processing chain, named the “Altimeter data Modelling and Processing for Land Ice” (AMPLI), provides topography estimations posted at ~330 m along the satellite track. Using ICESat-2 as a reference mission, we evaluated the performance of the AMPLI software over the Antarctic ice sheet. The median bias between Sentinel-3 AMPLI and ICESat-2 ATL06 nearly co-located measurements is estimated at +12 cm, on average over the Antarctic ice sheet. This surface height difference exhibits spatial variations over the Antarctic ice sheet, of the order of few decimetres. These divergences are most likely induced by the terrain characteristics (slope and roughness), and snow volume scattering affecting Ku-band altimetry measurements. The performance improvement is substantial compared to the ESA level-2 products, in particular over the ice sheet margins. For example, where the surface slope is greater than 0.5°, the median bias and the median absolute deviation relatives to ICESat-2 ATL06 are reduced by about 83 % and 90 %, respectively. We also assessed the capability of Sentinel-3 to monitor Surface Elevation Change (SEC) over the Antarctic ice sheet. The comparison between SEC maps from Sentinel-3 AMPLI and ICESat-2 ATL15, calculated over the 2019–2022 period, shows a Pearson correlation of 0.92. The study highlights the benefit of radar signal modelling, in synergy with high resolution Digital Elevation Model (DEM), for reducing the slope-induced errors over ice sheets. The results emphasize the potential of the Sentinel-3 constellation for ice sheet mass balance studies.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.
Jérémie Aublanc, François Boy, Franck Borde, and Pierre Féménias

Status: open (until 22 Jul 2024)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Jérémie Aublanc, François Boy, Franck Borde, and Pierre Féménias
Jérémie Aublanc, François Boy, Franck Borde, and Pierre Féménias

Viewed

Total article views: 83 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
63 15 5 83 8 3 4
  • HTML: 63
  • PDF: 15
  • XML: 5
  • Total: 83
  • Supplement: 8
  • BibTeX: 3
  • EndNote: 4
Views and downloads (calculated since 10 Jun 2024)
Cumulative views and downloads (calculated since 10 Jun 2024)

Viewed (geographical distribution)

Total article views: 80 (including HTML, PDF, and XML) Thereof 80 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 12 Jun 2024
Download
Short summary
In this study we developed an innovative algorithm to derive the ice sheet topography from Sentinel-3 altimetry measurements. The processing chain is named the “Altimeter data Modelling and Processing for Land Ice” (AMPLI). The performance improvement is substantial compared to the official data generated by the ESA ground segment. With AMPLI, we show that Sentinel-3 is able to estimate the Surface Elevation Change of the Antarctic ice sheet with a high level of agreement to ICESat-2.