Abstract. Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere-ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR) for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that, theoretically, surface height variations can be retrieved with relative errors ≤ 0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.

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[1] This paper examines a hydrographic response to the wind-driven coastal polynya activity over the southeastern Laptev Sea shelf for April-May 2008, using a combination of Environmental Satellite (Envisat) advanced synthetic aperture radar (ASAR) and TerraSAR-X satellite imagery, aerial photography, meteorological data, and SBE-37 salinity-temperature-depth and acoustic Doppler current profiler land-fast ice edgemoored instruments. When ASAR observed the strongest end-of-April polynya event with frazil ice formation, the moored instruments showed maximal acoustical scattering within the surface mixed layer, and the seawater temperatures were either at or 0.02°C below freezing. We also find evidence of the persistent horizontal temperature and salinity gradients across the fast ice edge to have the signature of geostrophic flow adjustment as predicted by polynya models.

In this study, we compare colocated near‐coincident X‐, C‐, and L‐band fully polarimetry SAR satellite images with helicopter‐borne ice thickness measurements acquired during the Norwegian Young sea ICE 2015 (N‐ICE2015) expedition in the region of the Arctic Ocean north of Svalbard in April 2015. The air‐borne surveys provide near‐coincident snow plus ice thickness, surface roughness data, and photographs. This unique data set allows us to investigate how the different frequencies can complement one another for sea ice studies, but also to raise awareness of limitations. X‐band and L‐band satellite scenes were shown to be a useful complement to the standard SAR frequency for sea ice monitoring (C‐band) for lead ice and newly formed sea ice identification. This may be in part be due to the frequency but also the high spatial resolution of these sensors. We found a relatively low correlation between snow plus ice thickness and surface roughness. Therefore, in our dataset ice thickness cannot directly be observed by SAR which has important implications for operational ice charting based on automatic segmentation.

The launch of the first German radar satellite TerraSAR-X in 2007 opened a new era in spaceborne radar remote sensing. So far the applicability for the high-resolution prospection of upstanding and, especially, buried monuments was limited because of the low resolution of the former sensors. TerraSAR-X, however, provides us with images with a spatial resolution of up to 1 m. The satellite operates in the so-called X-band with a frequency of 9.65 GHz. Therefore it is supposed that there is no possibility to penetrate the soil with this sensor. To testify and analyse the benefit of TerraSAR-X in archaeological geophysics, we chose as a test site a Roman fortress in Syria. The site was chosen as we already have GPR data of the same area for a comparison and for the verification of the actual penetration depth. Our results revealed that it is possible to resolve superficial and even buried structures in the data set, which provides evidence that the X-band waves can penetrate the soil. This paper shows our results of the survey and an estimation of the possible penetration depth of TerraSAR-X. Copyright