A reconstruction of summer sea ice conditions in the Labrador Sea using Hudson's Bay Company ships' log-books, 1751 to 1870

Abstract

The sailing ships' log-books contained in the Hudson's Bay Company Archives were used to reconstruct summer sea ice conditions in the Labrador Sea from 1951 to 1870. This reconstruction involved the development of an ice severity index, derived from a content analysis of the word roots and phrases in the ice descriptions, and the comparison of historic encounters with the presence of ice in the same sector in 1965. The icy severity index obtained for the Labrador Sea did not demonstrate a significant relationship with other ice severity indices derived for Hudson Strait and Hudson Bay. The ice severity index displayed some similarities to ice severity derived for other regions of the Labrador Sea. A highly significant volcanic signal was found in the ice severity index indicating a relationship between volcanic dust and the atmospheric circulation responsible for late ice retreat in the Labrador Sea. The number of icebergs sighted each year was also estimated for the period 1751 to 1870.