SAR Retracking in the Arctic: Development of a year-round retrackers system

The year-round retrackers system includes per month the most accurate retracker for ocean waveforms and the best precision retracker for sea ice and leads. To remove the bias caused by combining different retracking algorithms, four bias removal strategies are developed and evaluated on their accuracy and precision performance. The retrackers system with the primary peak centre of gravity as a basis retracker and a mean bias removal approach performed best, as it has a precision improvement of 47.1% with respect to retracking all waveform classes with the primary peak COG retracker solely. By applying the developed optimal retrackers system and using the bias removal strategy, the mean standard deviation of the altimeter measurements in the Kara Sea study area is reduced from 6.7 cm to 3.6 cm.