The retrospective investigation consists of a model hindcast for more than a half century using ‘reality-based’ atmospheric forcing to drive the model. The reality-based forcing consists of 1948-2004 NCEP/NCAR reanalysis forcing. This part of the research focuses on GOAL 1.
Data sets from the retrospective investigation can be found here.
Five movies:
You might find interest in five movies. The first movie(1) shows the seasonal and interannual variability of model simulated sea ice thickness and satellite observed ice edge from 1979 to 2003. The movie displays the decline of arctic sea ice since 1979. The second movie(2) illustrates the shrinking of arctic summer (September) sea ice, while the third movie(3) shows the variability of winter (March) sea ice. The fourth , movie(4) shows the variability of the Atlantic Water layer circulation in the Arctic Ocean. The latest movie movie(5) shows the rapid retreat of arctic sea ice in summer 2007 and 2008.
Comparison with satellite ice concentration:
 The above figure shows monthly mean model simulated sea ice thickness (m) and satellite observed ice edge (white line) for 9/1979 and 9/2003. The model results indicate a significant reduction in arctic sea ice in 2003, in comparison with 1979. |
 This reduction is also illustrated by the following satellite observations of the minimum ice concentration for 1979 (left) and 2003 (right). |
| Comparison with submarine ice draft: |
 The above figure shows that the simulated ice draft is in a reasonably good agreement with submarine observations of ice draft along the tracks of submarine cruises in 1987-1997. W: winter cruise; S: summer cruise. |
Sea ice volume and NAO: |
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| The above figure shows the simulated ice volume for the northern hemisphere (NH) and the North Atlantic Oscillation (NAO) index. The simulated NH ice volume has been decreasing steadily since 1960s while the NAO has shifted to a generally positive phase. According to the model, there were a few low-ice years in the 1950s, but 2002-2003 had the least sea ice in the NH. |
Animations: