SAR interferometry and offset tracking approaches for glacier movement estimation in the Himalaya

We have used the repeat pass Synthetic Aperture Radar (SAR) intensity tracking for two dimensional (2-D) glacier surface motion estimation using X-band data. It has been observed that the viability of SAR interferometry (InSAR) often is limited by coherence loss over glaciers in land locked regions using SAR data pairs of more than one-day temporal baseline. An alternative to InSAR is the intensity tracking approach, which relies on intensity cross-correlation for estimation of subpixel surface motion in range and azimuth directions. In this work we have applied this approach for two-dimensional glacier surface motion estimation in northwestern (NW) Himalayas, using TerraSAR-X (TS-X) spotlight mode high-resolution data pairs of 11 day, 22 day and 33 day temporal separation of August- September, 2008. Gangotri glacier motion in NW Himalayas are studied and analyzed over short period and it has been observed that its motion was 10 cm/day. The technique is found to be highly appropriate for monitoring the flow rate of glaciers in Himalayas and can be used to routine monitoring of glacier characteristics and dynamics.