Retrieving the grounding lines of the Riiser-Larsen Ice Shelf using Sentinel-1 SAR images

Abstract

Accurately locating and studying grounding lines is essential for predicting the response of glaciers to climate change. However, it is challenging to find grounding lines since they are subglacial features. In this study, Sentinel-1 synthetic aperture radar (SAR) data were utilized to derive the grounding lines of the Riiser-Larsen Ice Shelf. A new method with inspiration drawn from multi-temporal baseline InSAR techniques is proposed. It takes advantage of the temporal consistency of the vertical displacement gradients and identifies grounding zones pixel-by-pixel on a stack of double differential interferograms, thereby providing grounding line proxies. As it fully exploits coherent signals in both spatial and temporal domains, the maximum possible number of grounding zone pixels can be obtained. Moreover, due to the introduction of the concept of the temporal consistency, the method can cope with short term grounding line fluctuations to some extent and may mitigate the influences of atmospheric disturbances and residual ice displacements. The resulting grounding lines are compared with the MEaSUREs Antarctic grounding line product. The comparison confirms the effectiveness of the proposed method and corroborates that the Riiser-Larsen Ice Shelf should have not undergone significant changes over the past few decades.

Keywords

• antarctica
• ice shelf
• grounding line
• radar interferometry
• sentinel-1 images