SAR interferometry and Speckle tracking approach for glacier velocity estimation using ERS-1/2 and TerraSAR-X spotlight high resolution data

Glacier retreat and advance is general phenomenon in Himalayan region due to change in climatic conditions. For quantifying the global warming effects on local scale glacier system monitoring and estimating its dynamic geophysical parameters viz. movement and volume change are important. In this study glacier movement estimation is attempted in north western Himalayan region using spaceborne InSAR technique, which is based on preserving the coherence between two acquisitions of the same scene. It is observed that ERS-1/2 tandem data give high correlation over Gangotri glacier and Siachen glacier and movement in LOS direction is deciphered. However, with the use of SAR Speckle tracking method two dimensional (Azimuth and range directions) velocities of glaciers can be obtained. In this study attempt has been made to measure 2-D velocity components of Gangotri glacier. New generation TerraSAR-X (TS-X) high resolution spotlight mode (HS), single look slant range complex (SSCs) data of 28^th August, 2008, 08^th September, 2008, 19th September, 2008 and 30^th September, 2008 are exploited for this study. Interferogram, coherence image and intensity image are generated. It is observed that Interferometric SSC data of 28^th August, 2008 and 08th September, 2008 give some fringes outside glacier area and complete decorrelation is shown on the Gangotri glacier due to high movement of glacier.