Seasonal surface displacement derived from DInSAR, Rankin Inlet, Nunavut

Abstract

This map shows the relative ground surface displacement between the major terrain units during one summer in the area of Rankin Inlet. The ground displacement was derived using differential interferometric synthetic aperture radar (DInSAR) data for the summer of 2015. DInSAR data came from the Canadian RADARSAT-2 satellite which operates with a C-band SAR. Stable ground represents locations where either no vertical change was calculated or where displacement was within the expected range of error (± 1.0 cm). Downward displacement represents, in general, ground surface lowering (subsidence) on the order of 1.0 to 2.5, 2.5 to 4.0, 4.0 to 6.0, 6.0 to 8.5, and 8.5 to 14.0 cm. Other possible causes of apparent downward displacement could be associated with downward surface water table movement throughout the summer and sediment erosion. Upward displacement represents a surface rise of 1.0 to 5 cm, which is only 0.3% of the total coverage of the DInSAR map. Areas of no data result from a loss of interferometric coherence. These are typically water and other relatively smooth surfaces from which there is no radar return, or where there has been significant ground surface disturbance and the radar returns cannot be correlated.