Estimates of Arctic Sea Ice Extent and Concentration from 1901-1956 Now Available

This new data set of image and shapefiles provides estimates of Arctic sea ice extent and concentration from 1901 to 1956 created from a collection of historic, hand-drawn sea ice charts from the Danish Meteorological Institute (DMI). The original DMI charts are based on compiled observations of ice conditions reported by a variable network of national organizations, shore-based observers, scientific expeditions, and ships. These were used to create sea ice extent and concentration fields for each summer month from 1901 to 1956 by manual, subjective interpretation of scanned versions of the charts. To access the data and learn more about it, see the Arctic Sea Ice Concentration and Extent from Danish Meteorological Institute Sea Ice Charts, 1901-1956 Web page.