Fiducial Reference Measurements (FRM) for Sentinel-3 land altimetry

Knowing that Antarctic ice loss could contribute up to 30 cm to sea level rise by 2100, assessing Antarctic mass balance, and therefore its contribution to sea level rise, is a crucial scientific issue. This project aims to improve the accuracy of Antarctic mass balance estimates by providing continuous time series of snow surface elevation in Terre Adélie, designed for calibration/validation of Sentinel 3 (S3) radar altimetry measurements. This kind of ground-truth-based satellite calibration/validation measurements is one of the priorities of the European Space Agency’s (ESA), through the deployment of observations based on the Committee on Earth Observation Satellites “FRM” standard, i.e. with a standardized absolute accuracy available at satellite scale.
Here, we propose to deploy two stations for calibration/validation of altimetry measurements at strategic crossing points of the Sentinel 3a and 3b satellites orbits at about 60 km and 130 km from the coast. To extend our measurements to the kilometer scale (the scale seen by the satellite), surface elevation will be extrapolated using UAV surveys of areas covering the ground positions of possible satellite orbits around the stations. The stations will be installed during the 2025-26 season, a few kilometers from the SAMBA observatory (IPEV project n°411) measurements, along the logistical traverse to Dome C. The stations will then be revisited in 26-27 and 27-28 for maintenance. Operations will be carried out at the same time as the Glacioclim-SAMBA raid. UAV flights will be achieved during the installation and the first maintenance visit. Data will be distributed via a FRM datahub offering information for various surface states on a global scale, enabling stakeholders of the S3 mission Performance Center to carry out various calibrations/validations.