Speaker
Description
Microwave remote sensing has become an indispensable tool for monitoring the polar regions, as signal penetration into dry snow and ice makes Synthetic Aperture Radar (SAR) sensitive to subsurface structures [1]. This sensitivity generally increases toward longer wavelengths, providing access to deeper englacial scattering contributions [1,3,4]. ESA’s BIOMASS mission, launched in April 2025, is the first spaceborne P-band SAR mission and provides fully polarimetric observations with unprecedented potential for investigating the internal structure of the Antarctic Ice Sheet.
First BIOMASS observations over Antarctica reveal pronounced spatial variations in the polarimetric response across different glaciological environments, including transitions between glacier facies, areas of strongly deformed ice, and regions influenced by mountainous topography. However, the physical origin of many of these patterns and their relation to subsurface ice structure require further investigation.
In this study [5], we investigate BIOMASS acquisitions from two crossing orbits over the Riiser-Larsen Ice Shelf and Lyddan Ice Rise region acquired in November 2025. The Lyddan Ice Rise forms a stationary obstacle within the surrounding floating ice shelf, forcing the ice flow to divert around it and producing zones of enhanced deformation. Airborne Radar Echo Sounding (RES) observations provide an independent reference for the englacial structure. In regions with comparatively undisturbed flow, the RES data show continuous internal layering, whereas toward the deformation zones around the ice rise these layers become increasingly tilted, folded, and disrupted.
The corresponding BIOMASS observations show systematic changes in the polarimetric scattering behaviour, particularly in the anisotropy and orientation-dependent response [2]. We investigate whether these signatures can be related to the deformation observed in the RES data. Surface and oriented-volume scattering models are used to reproduce the measured polarimetric response while accounting for variations in subsurface layer orientation and structural organisation. The comparison indicates that the pronounced polarimetric patterns around the Lyddan Ice Rise are more consistently explained by deformation-induced changes in internal structural organisation and anisotropy than by variations in mean layer tilt alone.
These first results demonstrate the sensitivity of spaceborne P-band polarimetry to deformation-related subsurface structure in Antarctic ice. Combining BIOMASS observations with RES measurements and polarimetric modelling provides a framework for physically interpreting these newly observed signatures. In the longer term, the extensive spatial coverage of BIOMASS may enable systematic identification of shear margins, deformation zones, and other structural features across Antarctica, providing new information on the relationship between englacial structure and ice dynamics.
[1] Rignot, E., et al. (2001). Penetration depth of interferometric synthetic-aperture radar signals in snow and ice. Geophysical Research Letters, 28(18), Art. no. 18.
[2] Cloude, S. (2010). Polarisation: applications in remote sensing (1st ed.). Oxford: Oxford University Press.
[3] Fischer, G. et al. (2019). Modeling Multifrequency Pol-InSAR Data from the Percolation Zone of the Greenland Ice Sheet. IEEE Transactions on Geoscience and Remote Sensing, Vol. 57, No. 4
[4] Schlenk, S. et al. (2025). Characterization of Ice Features in the Southwest Greenland Ablation Zone Using Multi-Modal SAR Data. The Cyrosphere
[5] Schlenk, S. et. al. (2026). Effects of Sub-Surface Ice Deformation in Polarimetric P-Band BIO-MASS SAR Data in Antarctica. (under Review)