Tide-free flow velocity and strain rate of Campbell Glacier Tongue, East Antarctica, measured by InSAR

Abstract

Measurement of strain rate of a floating glacier is critical to the investigation of detailed flow regime and crevassing mechanism of the ice. We measured the surface deformation of Campbell Glacier Tongue (CGT) in East Antarctica from the 14 COSMO-SkyMed one-day tandem differential interferometric SAR (DInSAR) image pairs obtained in 2011. The vertical tidal deflection of CGT in each DInSAR image was estimated by using the tide deflection ratio generated by the double-differential interferometric SAR technique. By removing the vertical tidal deflection from the DInSAR signals, we derived the tide-corrected ice velocity and strain rate of CGT. The crevasses in CGT formed perpendicular to the axis of the most tensile strain rate, from which we found that they were generated by the gravitational ice flow and not by the vertical tidal deflection.