Velocity Anomaly of David Glacier, East Antarctica, Observed by Double-Differential INSAR

This research observed variation of flow velocity on the David Glacier, East Antarctica observed by using Sentinel-1A satellite. Because of the 12-day revisit cycle, relatively slow-flowing area was observed. Using double-differential InSAR (DDInSAR) technique, we could find the circular shaped velocity anomaly. We combined the ascending and descending DDInSAR images to figure out the direction of the true displacement over the anomaly. As a result, the circular anomaly appears mainly to be a vertical movement, not in the flow direction. This vertical movement in the David Glacier, where subglacial lakes are known to exist, can be thought of as a signal of water level change of a subglacial lake forming a subglacial channel system.