Sea ice topography from TanDEM-X interferometric SAR

An example of a preliminary TanDEM-X InSAR image over sea ice close to the Axel-Heiberg-Islands in the Canadian Archipelago.
(TanDEM-X data provided by DLR)

Syntetic Aperture Radar (SAR) is a coherent imaging radar technique available on many satellite platforms. The term coherent means in this context that a single wavelength with a known phase and amplitude is emitted and received. Using more than one observation or more than one instrument allows to convert the phase difference between the two acquisitions into a height variation, i.e., surface topography. The further apart these acquisitions, the higher the topographic resolution. This way of processing two SAR scenes over the same region is called Interferometric SAR (InSAR).

The TanDEM-X mission was operated in a science mode where also scenes with very long baselines (distances between the sensors) were taken during 2015 and 2016. The resulting higher topographic resolution can be exploited to resolve height differences in sea ice covered areas such as:

- pressure ridges
- icebergs
- leads