Measurement of sea ice

Measurement of sea ice is important for safety of navigation and for monitoring the environment, particularly the climate. Sea ice extent interacts with large climate patterns such as the North Atlantic oscillation and Atlantic Multidecadal Oscillation, to name just two, and influences climate in the rest of the globe.

The amount of sea ice coverage in the arctic has been of interest for centuries, as the Northwest Passage was of high interest for trade and seafaring. There is a longstanding history of records and measurements of some effects of the sea ice extent, but comprehensive measurements were sparse till the 1950s and started with the satellite era in the late 1970s. Modern direct records include data about ice extent, ice area, concentration, thickness, and the age of the ice. The current trends in the records show a significant decline in Northern hemisphere sea ice and a small but statistically significant increase in the winter Southern hemisphere sea ice.

Furthermore, current research comprises and establishes extensive sets of multi-century historical records of arctic and subarctic sea ice and uses, among others high-resolution paleo-proxy sea-ice records.^[1] The arctic sea ice is a dynamic climate-system component and is linked to the Atlantic multidecadal variability and the historical climate over various decades. There are circular changes of sea ice patterns but so far no clear patterns based on modeling predictions.