This polygon shapefile contains ice observations in the Arctic region for March 18, 1968. The ACSYS Historical Ice Chart Archive presents historical sea-ice observations in the Arctic region between 30ºW and 70ºE. The earliest chart dates from 1553, and the most recent from December 2002.
If you use this data, please refer to it using this citation:
ACSYS, 2003. ACSYS Historical Ice Chart Archive (1553-2002). IACPO Informal Report No. 8. Tromsø, Norway: Arctic Climate System Study.