5217 20210630113937.0 10.3390/rs13061164 DOI SCART-2021-0038 Pinat, Elisa Long-Term Snow Height Variations in Antarctica from GNSS Interferometric Reflectometry 2021 The increased melting rate of the Antarctic Ice Sheet is a critical consequence of climate change and a driving factor of global sea level rise. Acquiring reliable estimates of the Antarctic Ice Sheet mass balance is essential for trustworthy predictions of their evolution and future contribution to sea level rise. Snowfall is the primary mass input to the Antarctic Ice Sheets. Its long-term spatio-temporal variability is however not well known and relies mostly on atmospheric models, rather than local measurements. Uncertainty in snow accumulation rates results in errors on the mass budget estimation. In this study, GNSS Interferometric Reflectometry is exploited to assess the long-term variations of snow accumulation and ablation processes. Eight antennas belonging to the POLENET network are considered, together with the ROB1 antenna, deployed in the East part of Antarctica by the Royal Observatory of Belgium. For ROB1, which is located on an ice rise, we highlight an annual variation of snow accumulation in April-May (∼ 30-50 cm) and ablation during spring/summer period, but no overall ice meltdown is observed in the 2013-2016 period. For POLENET, one antenna does not show any overall trend, four exhibit a positive trend and three antennas show on the contrary a net negative trend over the considered time window, reaching for the Lower Thwaites Glacier antenna a maximum meltdown of ten meters in ten years, with a conservative uncertainty of one meter. NO Defraigne, Pascale Bergeot, Nicolas Chevalier, Jean-Marie Bertrand, Bruno Remote Sensing 13 6 1164 elisa.pinat@observatoire.be published in REFERD