Variability of fast-ice thickness in Spitsbergen fjords

Abstract

Detailed measurements of sea-ice thickness and snow on sea ice were recorded at different locations in fjords along the western coast of Spitsbergen, the largest island in the Svalbard archipelago, in 2004. Data corresponding to the ice situation before and after melt onset were collected for Kongsfjorden and Van Mijenfjorden, while Hornsund was investigated once during early spring. Profiles of total thickness (snow plus ice thickness) were measured, together with some snow-thickness measurements. Total thicknesses were measured with a portable electromagnetic instrument and at selected sites by drilling. The three fjords show some differences in measured thicknesses, connected to individual conditions. However, total thickness does not differ substantially between the three fjords before melt onset. The modal total thickness for all three fjords before melt onset was 1.075 m, and the corresponding modal snow thickness was 0.225 m (bin width 0.05 m). Long-term Kongsfjorden ice-thickness data since 1997 show that the maximum ice thickness varies significantly interannually, as observed at other Arctic sites. The average maximum ice thickness for Kongsfjorden was 0.71 m (years 1997-98, 2000 and 2002-05), and the respective average maximum snow thickness was 0.22 m. In Kongsfjorden, 2004 was the year with highest maximum total thickness and snow thickness relative to the other years.