Fram Strait Sea Ice Volume Export Estimated Between 2003 and 2008 from Satellite Data

In the light of a reduced Arctic summer time sea ice extent it is of particular interest to monitor the sea ice volume flux out of the Arctic Ocean. Sea ice export through Fram Strait accounts for the largest portion of the total Arctic sea ice export and amounts to about 10% of the total sea ice mass of the Arctic Ocean. Interannual perturbations in the sea ice transport through Fram Strait can modify the major water mass formation processes in the Greenland Sea and further downstream with consequences for the deep water formation and global ocean circulation.

Satellite-based estimates of monthly winter sea ice volume exports through Fram Strait for the years 2003 to 2008 are presented. These are obtained from individual satellite observations of sea ice thickness, area, and drift. First, sea ice freeboard is inferred from ICESat laser altimeter observations and then converted to ice thickness estimates. Sea ice area and drift are derived from AMSR-E 89 GHz data. Retrieved sea ice thickness estimates compare within 0.5 m with the few ULS data available in the Fram Strait. The mean, minimum, and maximum observed monthly Fram Strait sea ice volume export amounts to 217, 92, and 420 km3/month, respectively. In comparison to former Fram Strait sea ice volume export estimates obtained during the 1990s our estimates are slightly smaller (-33 km3/month) but are within the natural variability and no significant change of the total amount of Fram Strait sea ice export can be observed.