Geometric and radiometric Calibration of a rotating multi-beam Lidar using a rotating tilted Platform

We developed a 24-year record revealing how river ice on the six largest Arctic rivers has changed under a warming climate. Using satellite images from the MODIS Terra and Aqua sensors, we monitored daily ice cover and seasonal freeze-up and breakup timing. On average, over 65 % of river segments show later freeze-up (~ 9 d), earlier breakup (~ 8 d), and shorter ice seasons (~ 14 d), revealing a clear signal of rapid warming across Arctic river systems.