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 (forecast starts on 8/1/2014).

Movie: hindcast/forecast of 2014 Arctic sea ice (forecast starts on 8/1/2014)
(To view the movie frame by frame, download it and use the free QuickTime Player to open it)


Movie: Zooming of the Chukchi and Beaufort seas
(To view the movie frame by frame, download it and use the free QuickTime Player to open it)


Movie: Zooming of the Northwest Passage region
(To view the movie frame by frame, download it and use the free QuickTime Player to open it)


Ensemble forecast of 9/2014 ice thickness and standard deviation (SD)
(white line is satellite observed ice edge for 9/2013 and black line is model predicted ice edge for 9/2014)


Comparison of the NCEP/NCAR surface air temperature (SAT) between 2014 and 2013.


Hindcast of September Arctic sea ice
 — white (black) line is satellite (model) observed (simulated) ice edge —

Links to some other activities for seasonal outlook of arctic sea ice

Work at NSIDC.
Work by Ron Lindsay
Work by Ignatius Rigor et al.

Important notice

The purpose of the seasonal predictions of arctic sea ice is for scientific research and education only. There are many uncertainties with the predictions and the results must be viewed with caution. The work is conducted at the Polar Science Center, Applied Physics Laboratory, University of Washington. Support is provided by NSF. Neither the Government nor the University of Washington nor any individual person makes any warranty, expressed or implied, or assumes any responsibility or liability for the use of the prediction results or any other results in this web site.


Zhang, J., and D.A. Rothrock: Modeling global sea ice with a thickness and enthalpy distribution model in generalized curvilinear coordinates, Mon. Wea. Rev., 131(5),  681-697, 2003.

Zhang, J., M. Steele, R.W. Lindsay, A. Schweiger, and J. Morison, Ensemble one-year predictions of arctic sea ice for the spring and summer of 2008, Geophys. Res. Lett., 35, L08502, doi:10.1029/2008GL033244, 2008.