Satellite remote sensing of sea-ice thickness and kinematics: a review

Observations of sea-ice thickness and kinematics are essential for understanding changes in sea-ice mass balance, interactions between the ice cover and the ocean and atmosphere and for improving projections of sea-ice response in a warming climate. These parameters are not directly observable with current sensor technology, but are derived from satellite altimetry and imagery. While there is progress in the retrievals of Arctic sea-ice thickness from satellite altimetry, approaches to address Southern Ocean ice thickness require additional attention. On the other hand, procedures to derive sea-ice motion from satellite imagery are more mature and better understood and have been employed to produce useful results for more than a decade. Adequate sampling of sub-daily ice motion, however, remains a challenge. Generally, satellite instruments provide large-scale coverage but the frequency of temporal sampling is limited by orbit characteristics. In this review, I focus on the approaches, uncertainties, sampling limitations and validation issues associated with the estimation of sea-ice thickness and motion. I provide a summary of current and anticipated capabilities for monitoring sea-ice thickness and kinematics from space. The prospects for continuing these measurements into the next decade, from a satellite remote-sensing perspective, are discussed.