Automated sea ice concentration analysis history at NCEP 1996-2012

In the years since the first implementation of sea ice concentration analysis, the analysis system has evolved. While the basics remain the same, there have been many changes in details – weather filtering, which instruments are used, how they are used, land masks, and so forth have all changed somewhat or very much. This note documents the evolution of the system from 1996, when the original note was published, until 2012, the date of the last major changes to the system.