Ground-based interferometric radar for velocity and calving-rate measurements of the tidewater glacier at Kronebreen, Svalbard

Abstract

Abstract This paper presents the first attempt to measure the calving rate and flow velocity of the front of a glacier using ground-based high-range resolution interferometric radar at a high temporal rate (2 Hz). The radar, operating at 5.75 GHz, is located ∽4 km from the calving front of Kronebreen, Svalbard. The radar measures a horizontal width of ∽700m of the front, and a range of 300 m. The latter includes the calving front and 250m up-glacier. We find that the glacier surface provides permanent scatterers, so spatially continuous movements at the front and at locations further up-glacier can be tracked. For ∽8 hours we measured a large increase in velocity at the calving front, which extended 30 m up-glacier, while further up-glacier the velocity was stable (∽2.5md–1) during the entire period. Two large calving events were identified during this survey, removing 25m of ice in the radar range direction normal to the ice front. The velocity of the front slowed to a stable 2.5md–1 after the events. During another data series the velocities were stable (∽2.5md–1) and no calving events were identified. The method is promising for carrying out studies of processes at a calving front, as it provides spatially continuous, high-frequency accurate velocities from a safe distance to the glacier.