This is the most recent version of these data.
The Arctic and Antarctic Research Institute (AARI) in St. Petersburg, Russia, produces sea ice charts for safety of navigation in the polar regions and for other operational and scientific purposes. Arctic charts from 1933 through 2006 are collected in this data set. Chart frequency and spatial coverage varies, but charts were compiled every 10 days during the navigation season, and monthly for the rest of the year, over most of the series. There is a gap with no charts from 1993 through 1996. Chart coverage focuses on the Northern Sea Route, although later charts extend into the central Arctic. The charts were compiled from a variety of data sources, with heavy reliance on regular reconnaissance flights for most of the series until 1992.