Daily observations of human ice observers at predefined stations

The data comprises all German ice observing stations as well as ice stations of international fairways of the Baltic and North Sea. Following the Baltic ice code the parameters given are: amount and arrangements of sea ice (ice concentration) ; stage of ice development (ice thickness); topography or form of ice; and navigation conditions in ice. This oberservations were coded and were extracted from old filing cards, compilations, monthly reports and GTS messages.