CryoSat-2 Estimates of Sea Ice Freeboard in the Greenland Sea of Arctic

Abstract:

Arctic region is one of the most important parts that contribute to the global climate system. As an important climatic indicator, sea ice has also undergone dramatic changes. Due to the limitations of poor geographical conditions and a lack of in-situ observations, knowledge about Arctic sea ice has not been explored well for a long time, furthermore it is especial difficult to get a high quality of Arctic Sea ice thickness information.

Equipped with a Ku-band SIRAL, CryoSat-2 has been launched in 2010 as an important European Space Agency Earth Explorer Opportunity mission. CryoSat-2 has the advantage of measuring the thickness of polar sea ice and monitoring changes in the ice sheets that blanket Greenland and Antarctica with high precision.

In this paper, the CryoSat-2/SIRAL radar altimeter data were used to retrieve the sea ice thickness in the Greenland Sea, Arctic, validated with the Ice, Cloud, and Land Elevation (ICESat) laser altimeter measurements from National Aeronautics and Space Administration (NASA) and Beaufort Gyre Experiment Program (BGEP) Upward Looking Sonar (ULS) measurements. Results show that the sea ice freeboard in Greenland Sea has a remarkable seasonal variation and presents an evident regional characteristics. As it show below, during the frozen season in autumn and winter the sea ice freeboard concentrated in around 0.23m , the average freeboard in Greenland Sea in June decreased to around 0.18m, the minimum freeboard 0.12m appeared in September. In the Western Greenland Sea near the Greenland and the Fram Strait with higher-latitude where multi-year ice occupy most has a larger freeboard around 0.3m in winter. In the south-eastern Greenland Sea with lower-latitude and shallow sea water, the freeboard composed by first-year ice concentrated in around 0.1m in winter. At the same time, the sea ice area also had seasonal variations, its maximum was in January and March, and minimum was in September.