Abstract

Kongsfjorden is located in West Spitsbergen, Svalbard archipelago. Its hydrography is influenced by the West Spitsbergen Current (WSC) transporting warm and saline Atlantic Water (AW) toward the Arctic basin. We assessed changes in fjord water properties over two decades (1999–2020) using summer hydrographic surveys performed by the Norwegian Polar Institute in the fjord, the adjacent shelf, and open ocean regions. The heat content (HC) and salinity within the fjord have increased driven by a larger inflow of AW. These trends are consistent with observations in neighboring Isfjorden but not mirrored in the properties of the WSC over the same timeframe. Therefore, hydrographic changes in these two fjords can be attributed to larger AW intrusions rather than variations in the upstream WSC properties. We hypothesize that the increased HC in Kongsfjorden is driven by shifts in the synoptic wind patterns and larger glacier meltwater release enhancing fjord shelf exchanges. Idealized modeling experiments revealed that although these modifications contribute by increasing the fjord’s HC, they explain only a small portion of the observed changes, suggesting that the availability of Atlantic Water on the shelf is the dominant factor.

Key Points

• The heat content (HC) in Kongsfjorden waters has increased over in 1999–2020 mainly due to an increasing contribution of Atlantic Waters
• Positive temperature and salinity trends in Kongsfjorden match those observed in nearby Isfjorden but not those of the Atlantic current
• Changes in the coastal wind field and glacier meltwater runoff contribute to increase HC by altering circulation patterns