Assessing small-scale deformation and stability of landfast sea ice on seasonal timescales through L-band SAR interferometry and inverse modeling

Abstract

Rapid environmental change and increases in use of shorefast ice by industry and coastal communities highlight the need for an approach to accurately assess landfast sea-ice stability on seasonal timescales. While stability can sometimes be inferred from field measurements, current methods are lacking robustness and the ability to be automated and applied over large areas and long time scales to ensure safety and document change in the context of transportation, indigenous ice uses and industrial development. This paper introduces an inverse model capable of reconstructing three-dimensional deformation fields from one-dimensional interferometric L-band Synthetic Aperture Radar (SAR) phase patterns. We apply this method at three landfast ice locations on the Alaska Beaufort Sea coast near Barrow and Prudhoe Bay. We find the small-scale displacements estimated from the model consistent with regional patterns of ice motion. Our study suggests that interferometry can provide planning and decision-support information for ice road development and structures operating within ice. Moreover, InSAR can potentially increase our understanding of sea ice on a fundamental level in terms of large-scale stability and long-term changes in ice dynamics.

An Interferometric Synthetic Aperture Radar (InSAR) Habitat Suitability Model to Identify Overwinter Conditions for Coregonine Whitefishes in Arctic Lagoons

“…; Dammann et al. ). The particular value of ϕ at a given pixel is not meaningful on its own, but variation of ϕ between pixels indicates a topographic slope or that one pixel has moved relative to the other.…”

“…In lagoons, floating ice will be subject to motion due to thermal expansion and contraction and vertical changes in water level that are detectable using InSAR techniques (Dammann et al. ; Dammann et al. ).…”

“…Sources of temporal decorrelation on sea ice and lagoon ice include excessive movement or other changes such as flooding or melting. An interferogram is created by measuring the interferometric phase (ϕ) differences between two images acquired at different times and can be used to determine displacement that occurred during the imaging period (Moreira et al 2013;Dammann et al 2016). The particular value of ϕ at a given pixel is not meaningful on its own, but variation of ϕ between pixels indicates a topographic slope or that one pixel has moved relative to the other.…”

“…; Dammann et al. ). However, this is a relatively new application of InSAR technology that has not yet been used to understand fish habitat.…”

“…This is a signal processing technique that can be used to measure surface motion by analyzing the phase differences between two SAR scenes acquired from coherent (i.e., correlated) viewing geometries (Bamler and Hartl 1998;Moreira et al 2013). InSAR techniques have been previously used to identify areas of bottomfast and floating ice in estuarine areas as well as for the identification of landfast ice in the Beaufort Sea (Meyer et al 2011;Yue et al 2013;Dammann et al 2016). However, this is a relatively new application of InSAR technology that has not yet been used to understand fish habitat.…”