Sea Ice Group

The sea ice group is part of the Marine Modeling and Analysis Branch of the Environmental Modeling Center. Our responsibility, loosely speaking, is ice anywhere in the world, particularly ice which is floating on water. We start with remote sensing, analysis, and data assimilation of sea ice information to obtain the best possible (automated) estimates of current sea ice conditions. Once we have sea ice conditions, which are of interest in their own right, we then use the information to improve the weather forecast model(s), and to run sea ice forecast models.

We emphasize automated regarding our analysis because our work supports sea ice analysis by the NWS Alaska Region, and a wide variety of users in the US and world. These users bring other data sets and methods to the analysis which may not be automatable, and can result in significant improvements in the final products relative to the strictly automatic. You may see the current day's automated analysis at http://polar.ncep.noaa.gov/seaice/Analyses.html. The 3 times per week Alaska Region analysis is at http://pafc.arh.noaa.gov/ice.php.

After running a daily analysis for a number of days, we start to have a lengthy period of coverage and start thinking about climatic uses. The automated analyses are therefore used by some climate groups, both for analysis and modeling. Our analyses are available from September 1995 to the present at http://polar.ncep.noaa.gov/seaice/Historical.html, via anonymous ftp to ftp://polar.ncep.noaa.gov/pub/cdas, and from 1979 to 1996 (as used by the NCAR/NCEP Climate Reanalysis Project. 1979 to 30 November 1991 was developed by Atsushi Nomura, then at the ECMWF) in ftp://polar.ncep.noaa.gov/pub/ice/reanl.ice . Because of interest in the sea ice climatology, climate change, and improving both sea ice and sea surface temperature analyses, longer time series with improved (and more consistent) methods will become available in the future.

The automated analysis have been used by the NWS global atmospheric models for their sea ice conditions since February, 1998. The automated analysis provides a daily, 1/2 degree resolution in latitude and longitude, condition for the models as opposed to the former method, which gave a 2 degree condition once per week. During spring and fall, the sea ice edge can move by 200 km (2 degrees) in a week. The new analysis is capable of resolving this fact for the weather models.

In addition to knowing where the ice is now, we would like to know where it is going to be. Sea ice coverage is important for shipping and fishing, as well as for weather forecast models. To support that effort we are developing a number of sea ice models. The simplest one, which is surprisingly useful in operations, is a sea ice drift model. This is currently operational for 16 day guidance. The developmental model is a model which predicts sea ice motion, concentration changes, and ice thickness. While still developmental it is available only to certain internal users. Once we're satisfied that the model makes sense, we will make it publicly viewable.


Sea Ice Group Publications

NCEP.EMC.Seaice@noaa.gov
Last Modified 6 June 2001