Measuring Arctic Sea Ice Motion in Real Time With Photogrammetry

The U.S. Naval Research Laboratory (NRL) has been collecting sea ice data in the Arctic, off the northern coast of Alaska, with an airborne system employing a radar altimeter, lidar, and a photogrammetric camera in an effort to obtain wide swaths of measurements coincident with CryoSat-2 track footprints. Because the satellite tracks traverse regions of moving pack ice, and the aircraft speed and measurement footprint are smaller than that of the satellite, it is necessary to know the local ice motion in order to plan and fly a full-coverage survey. With the advent of functional and real-time orthographic photogrammetric systems, we have developed a Real-Time Ice Motion Estimation (RTIME) system that permits the rapid determination of sea ice motion. RTIME enables tracking of specific patches of ice, allowing direct comparison of airborne data to satellite data on a point-by-point basis. This system should be of utility to other Arctic airborne science programs.