Forecast of Sea Ice Conditions

The state of the Arctic climate system is rapidly changing. These changes are impacting ecosystems, coastal communities, and economic activities. High-quality predictions of the sea-ice conditions are of outstanding interest. In the  Sea-Ice Outlook (SIO), for example, various international research groups are applying different approaches to predict the Arctic summer minimum sea-ice extent in September from the beginning of the melting season in May/June on. AWI is participating in the SIO since 2008 by using a coupled sea-ice ocean model (NAOSIM) forced by atmospheric surface boundary conditions of the past (ensemble approach).

While the strongest greenhouse gas induced changes are currently observed in the Arctic, it is also the area of the largest natural variability leading to a very low theoretically predictability. However, nobody knows at the moment exactly how large or low the predictability is. The methods applied for sea-ice predictions depend on the time-scales of the forecasts. For the very long time-scales (multi-decadal to century long) Earth System Models (coupled atmosphere-sea ice-ocean-land models) forced by greenhouse gas emissions are used. For shorter time-scales the quality of predictions depends much stronger on the initial state as for instance in weather prediction where a large network of atmospheric and land surface observations of different kinds is combined with an atmospheric model. With respect to the sea ice many of the data streams necessary for high-quality predictions are still in an infant state (CryoSat -2).