Sea ice and icebergs

The major topic of this chapter is space-borne synthetic aperture radar (SAR) surveillance of ocean regions that are permanently or seasonally covered with ice. Surveys of sea ice conditions are required for production of ice charts, and sequences of SAR images are used for monitoring movement and deformation of the ice. Ice charts show the regional distribution of open water areas and different ice types, often supplemented by additional information such as areal fractions of ice types and floe sizes. Ice drift is displayed in maps of vector fields, which may be complemented with data quantifying their errors or reliability and the degree of deformation. A less extensive but nevertheless important topic of this chapter is the surveillance of icebergs. Ice charts and information on ice movements and iceberg occurrences are essential for the safety of ship traffic and offshore operations, and for several scientific questions. Issues addressed here concern methods for retrieving information about ice conditions, using different SAR systems and technologies.