Sea ice index comprising data extracted from historical records of ship observed ice positions during Weddell Sea voyages between 1820-1843. Extracted data comprise information on the expedition ship and lead, type of document, the date on which the observation was made, the ship''s latitude and longitude at the time of the observation, comments on sea ice and sea ice present (1 if deemed present, 0 if not).

Publication assisted by Leverhulme Emeritus Fellowship EM-2022-042 to Professor Grant R. Bigg: "Extending the Southern Ocean marine ice record to the eighteenth century".