Interannual variations of freshwater content in Hornsund

Abstract

Salinity measurements have been used to calculate the freshwater content in Hornsund for the years 2001 to 2014. In 2011 there was significantly higher freshwater content in the fjord, compared to the other years, with a total freshwater content of 1.08 km3, when calculated with a reference salinity of 34.2. The high freshwater content in 2011 was attributed to the inflow of sea ice and sea ice meltwater of Barents Sea origin, that had been advected into the fjord from the shelf. The lowest amount of freshwater was found in July 2014. No good relashionship between estimations of variations in terrestial runoff and freshwater content in the fjord was found. The distribution of freshwater in Hornsund seems to be governed by wind conditions and the rotational dynamics in the fjord. The fractional contributions of meteoric water, sea ice meltwater, and seawater was calculated based on δ^18O and salinity measurements in September 2013. Significant amounts of meteoric water was found in the surface waters of the bays Burgerbukta and Brepollen. The δ^18O in Brepollen, the innermost bay of Hornsund, showed unusually high values compared to other δ^18O measurements taken in and around Svalbard. This was attributed to the possible existence of a hydrothermal vent or significant amounts of sea ice meltwater in the bay.