Glacier motion estimation using SAR offset-tracking procedures

TLDR

SAR offset‑tracking provides an alternative to differential interferometry for estimating glacier motion, especially when coherence is lost due to rapid, incoherent flow or long acquisition gaps. The study employs intensity‑based patch cross‑correlation and coherence‑based patch optimization to estimate glacier surface displacement in slant‑range and azimuth, and can combine azimuth offset‑tracking with slant‑range interferometry to produce two‑dimensional displacement maps from a single orbit configuration. The accuracy and application range of these two methods were evaluated using SAR images of the Monacobreen surge in Northern Svalbard between 1992 and 1996.

Abstract

Two image-to-image patch offset techniques for estimating feature motion between satellite synthetic aperture radar (SAR) images are discussed. Intensity tracking, based on patch intensity cross-correlation optimization, and coherence tracking, based on patch coherence optimization, are used to estimate the movement of glacier surfaces between two SAR images in both slant-range and azimuth direction. The accuracy and application range of the two methods are examined in the case of the surge of Monacobreen in Northern Svalbard between 1992 and 1996. Offset-tracking procedures of SAR images are an alternative to differential SAR interferometry for the estimation of glacier motion when differential SAR interferometry is limited by loss of coherence, i.e. in the case of rapid and incoherent flow and of large acquisition time intervals between the two SAR images. In addition, an offset-tracking procedure in the azimuth direction may be combined with differential SAR interferometry in the slant-range direction in order to retrieve a two-dimensional displacement map when SAR data of only one orbit configuration are available.