Seasonal Ensemble Forecasts of Arctic Sea Ice


The accelerated decline of arctic sea ice in recent years presents both challenges and opportunities. There will be enhanced fishing, resource extraction, and marine transportation in the Arctic Ocean but there also will be challenges for the local Native subsistence communities who use the ice cover as a hunting platform. To assist in the planning and management of economic and subsistence activities in the north polar regions, it is important to develop capabilities for seasonal forecasts of arctic sea ice. We plan to improve our existing seasonal ensemble forecasting system and use the system to predict sea ice conditions in the arctic and subarctic seas with lead times ranging from one month to three seasons. The ensemble forecasting system is based on a synthesis of a model, NCEP/NCAR reanalysis data, and satellite observations of ice concentration. The model is the Pan-Arctic Ice-Ocean Modeling and Assimilation System (PIOMAS, Zhang and Rothrock, 2003). The ensemble predictions are constructed by using the NCEP/NCAR atmospheric forcing from the previous 7 years (corresponding to 7 ensemble members) and the PIOMAS retrospectively estimated,  with assimilation of satellite ice concentration data, ice and ocean conditions at a given date at which ensemble predictions start. Details about the ensemble prediction procedure may be found in Zhang et al., 2008.
The September 2014 arctic sea ice extent is predicted to be 5.1 +/- 0.4 million square kilometers (this prediction and the animation below are updated on 8/1/2014)

Animations of Hind/Forecasts
Hindcast/Forecast of 2014 arctic
sea ice (forecast starts on 8/1/2014)
Zoom on NW- Passage