The English version of our glossary is currently under construction and will be regularly updated.
“Altimeter missions” are used to measure the elevation of the Earth’s surface, and therefore also the elevation of the sea-ice surface.
Laser, lidar and radar altimeters are used in aircraft and on satellites to measure their altitude above our planet’s physical surface. Lidar and laser altimeters emit collimated pulses of light and measure the time it takes for reflected pulses to reach a receiver. This transit time, cut in half, is then converted into units of distance. Radar altimeters work in much the same way but use radio frequencies.