SITHOS (Sea Ice Thickness Observation System) is also a three-year EU Framework 5 project. The Nansen Environmental Remote Sensing Centre (NERSC) will co-ordinate six institutions in the development of an integrated system for measuring sea ice thickness in the Arctic Ocean. Several approaches for obtaining ice thickness will be used, including novel flexural-wave methods, remote sensing and electromagnetic induction techniques. SAMS’ role is to provide data from UK submarines and aid in the development of the novel tiltmeter-based instruments. Data will be used to improve sea ice models and validate the new CRYOSAT satellite sensors. The resulting synoptic thickness monitoring network will be used to investigate the postulated dramatic thinning in the Arctic Ocean sea ice cover as a result of climate change.