Sea-ice is formed from ocean water that freezes, whether along coasts or to the sea floor (fast ice) or floating on the surface (drift ice) or packed together (pack ice). The most important areas of pack ice are the polar ice packs. Because of vast amounts of water added to or removed from the oceans and atmosphere, the behavior of polar ice packs have a significant impact of the global changes in climate.
Copernicu Sentinel-1's SAR mission and Sentinel-3's SLSTR mission support sea-ice monitoring. SLSTR also monitors sea-ice temperature. Sentinel-3's ALT mission supports sea-ice monitoring.