Variation in Average Surface Velocity Estimation of Tidal and Mountain glacier using optical and SAR microwave Remote Sensing.

Glacier melting or accumulation is a key indicator of the ongoing climate change. Arctic and Himalayan glaciers form an important part of the cryoshphere. Kongsbreen, Kronoebreen and Infantfonna are some among the fast flowing tidal glaciers in Svalbard Region. The Bhadal glacier, Kangra in the Himalayan Region is a significant mountainous glacier feeding the Bhadal Nala. Both have been an area of research for decades to understand the variations in climate. Due to remoteness of the study regions, an attempt has been made to use remote sensing techniques to estimate the glacier surface velocity of these glaciers at both of the regions. In the present study, both the optical and the SAR satellite data were used to estimate glacier velocity. The Optical Feature Tracking method is used to estimate glacier velocity with LANDSAT 8 OLI optical dataset on annual scale. Also the Offset Tracking method which makes use of Synthetic Aperture Radar (SAR) datasets was also used to estimate the seasonal change in the velocity in these glaciers at seasonal scale. Using Optical Feature Tracking the maximum surface velocity of the Kongsbreen, Kronebreen and Infantfonna glaciers combined is estimated to be 2.49m/day (2016-2017), 2.54m/day (2017-2018) and 2.69m/day (2018-2019). The maximum average velocity using Offset Tracking Method is 2.57m/day (2017), 2.54 m/day (2018), 2.72 m / day (2019). The results for the Bhadal Glacier will be presented later on. The increase in velocity is suggestive of decrease or loss of glacial mass for both the regions. It has been observed that for Tidal glaciers the results of Optical Feature Tracking and Offset Feature Tracking are quite comparable whereas for the Mountain Glacier Offset Feature Tracking provides more accurate value as Optical Feature Tracking is subjected to less coherence. Overall results are suggestive of impact of climate change on the glaciers as both of them have increased rate of melting. KEYWORDS: Svlabard, DinSAR, Glacier Surface Velocity, Offset Velocity, Optical Feature Tracking, Bhadal Glacier