Accuracy and Performance of CryoSat-2 SARIn Mode Data Over Antarctica

The instrument onboard CryoSat-2 has a new measurement mode to improve performance on the steeper margins of the ice sheets where conventional radar altimetry has been limited in accuracy and coverage. We assess the accuracy of CryoSat-2 synthetic aperture radar interferometric (SARIn) mode data using data from Geoscience Laser Altimeter System onboard ICESat and also compare coverage with conventional altimetry. Biases, exceeding 4 m, were ubiquitous in areas with surface slopes above about 0.9°. Over the ice shelves and the interior of the ice sheet, the bias was less than 50 cm but appeared to be sensitive to snowpack density. We find that the accuracy and coverage of CryoSat-2 SARIn mode data is significantly better than for previous satellite radar altimeter missions for slopes up to 1°.