In 1995, the National Ice Center (NIC) digitized the 1972 – 1994 unclassified hardcopy sea ice chart archive using services provided by the National Climatic Data Center (NCDC) in Asheville, NC. NCDC digitized all charts using a digitizing tablet and customized software on a personal computer. The charts were digitized as vector data, and then converted to ASCII gridded fields in the World Meteorological Organization’s Sea Ice in Gridded Format (WMO SIGRID). This data was released in July 1996 on the Arctic and Antarctic Sea Ice Data CD-ROM version 1.0.
In 1996, NIC agreed to undertake an Arctic data re-analysis and conversion project which would make its historical or "legacy" data more useful for environmental research under the auspices of the Gore-Primakov Commission Environmental Working Group (EWG). In undertaking this legacy data digitization project, NIC intended to review and correct all its historical weekly ice analyses in order to provide the most accurate data possible for the production of an ice climatology in the Arctic. NIC contracted Naval Research Laboratory (NRL) to import the "raw" ASCII SIGRID files into an ARC/INFO GIS gridded format in a polar stereographic projection to facilitate data viewing, revision and climatology computation.
In January 1997, the NIC became aware that many SIGRID files still contained errors in ice code attribute information and in some cases, depiction of ice region boundaries, and undertook a major Arctic data correction. This extensive data correction is now complete.
The NIC plans to re-issue this corrected Arctic data on a CD-ROM in January 2000. This re-release will include the following:
During the development and subsequent release of the new "NIC Historical Ice Data
CD-ROM" Arctic data from 1972-1994 will be made available via our website. The data
is organized by year and contains the following formats:
After January 2000, this data is available by requesting the CD-ROM via NIC official archive center NSIDC.