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

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 combining ̃4 km from the calving front of Kronebreen, Svalbard. The radar measures a horizontal width of ̃700 m of the front, and a range of 300 m. The latter includes the calving front and 250 m 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 (̃2.5 m d-1) during the entire period. Two large calving events were identified during this survey, removing 25 m of ice in the radar range direction normal to the ice front. The velocity of the front slowed to a stable 2.5 m d-1 after the events. During another data series the velocities were stable (̃2.5 m d-1) nd 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.