Estimation of Sea Ice Freeboard from SARAL/AltiKa Data

Abstract

An attempt has been made to derive sea ice freeboard from Ka-band Altimeter (SARAL/AltiKa) over Arctic region for 15 March–15 April 2013 (spring) and 15 September–15 October 2013 (autumn). A waveform template matching technique is employed for classification of leads and floe pixels. The estimated sea ice freeboards were found in close agreement with “Operation IceBridge quick look” freeboards (RMSD = 0.30 m). The differences between the two freeboards were largely due to snow layer over sea ice (R = 0.8). The estimated freeboards were of the order of 0.08–0.15 m during the two seasons.

Keywords:

• SARAL/AltiKa altimeter
• arctic region
• sea ice freeboard
• Operation IceBridge data
• altimeter waveforms

Acknowledgements

NASA's Operation IceBridge (OIB) and Ocean & Sea Ice-Satellite Application Facility (OSI SAF, EUMETSAT) are acknowledged for providing freeboard, snow depth, ice edge and ice type data. Authors are also grateful to Indian Space Research Organisation (ISRO) and Centre National d'Etudes Spatiales (CNES, France) for providing altimeter data.