Revisiting Observations of Arctic Sea-ice Motion and Deformation To Investigate Bounds of Sea-ice Variability.
Abstract
The Arctic sea ice is an important part of the northern polar climate system. Individual records of sea-ice drift in the Arctic were obtained through the last century. Observa- tions with high spatial or temporal coverage start in the 1970's when remote observa- tions of sea-ice motion are available from satellite-based instruments and in situ from drifting buoys. In the climatology of Arctic sea-ice drift the clockwise Beaufort Gyre, a northward motion off the Siberian Coast, and a south-eastward drift from the North Pole towards Fram Strait, have been identified. During recent decades this picture of Arctic ice motion has shifted away from the baseline state in response to changed at- mospheric conditions. Here we investigate high-resolution time-series of ice motion derived from IABP drifting buoys to identify further patterns of preferred ice motion in the Arctic. These can be associated with atmospheric regimes by correlating the two- dimensional variance of the buoy-derived ice velocities with the horizontal gradient of the mean sea-level pressure. Changes in the spatial pattern of regional meander coeffi- cients for the sea-ice motion provide further evidence for repeated transitions between patterns of ice motion in dependence to the atmospheric forcing. This is supported by dynamic frequency spectra of sea-ice divergence, which suggest damping of subdaily deformation cycles during low AO years. For regions with persistent buoy coverage (e.g., the western Arctic) time-series of sea-ice motion and deformation characteris- tics have been constructed. The identification of a dominant spatial pattern of sea-ice motion and deformation in response to changing atmospheric forcing is then used to explain the variability seen in Arctic ice extent and volume.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27..285H