Radar altimetry measurements over antarctic ice sheet: A focus on antenna polarization and change in backscatter problems

We show that waveform distortions due to snow characteristics fluctuation are complex. In the central part of the East Antarctica, the height and the leading edge width fluctuations vary together while elsewhere, height fluctuations may occur with no variations in the waveform shape, mostly during winter. As a consequence, these induced errors cannot be corrected with solely the help of the backscatter: waveform shape parameters are also needed. They are however not enough to fully correct these two errors. We propose an empirical correction for these effects. We show that crossover differences may be significantly reduced to up 22 cm. In terms of volume change, the estimation may vary up to 4 cm/yr at cross-overs depending on the correction used and is reduced in average to 2.3 cm/yr with our correction. The difference between the height trends estimated with both corrections is weak in average but may locally reach 5 cm/yr with a clear geographical pattern.