Oceanographic monitoring in Hornsund fjord, Svalbard

Abstract. Several climate-driven processes take place in the Arctic fjords. These include ice-ocean interactions, changes in biodiversity and ocean circulation patterns, as well as coastal erosion phenomena. Conducting long-term oceanographic monitoring in the Arctic fjords is, therefore, essential for better understanding and predicting global environmental shifts. Here we address this issue by introducing a new hydrographic dataset from Hornsund, a fjord located in south-western part of Svalbard archipelago. Hydrographic properties have been monitored with vertical temperature, salinity and depth profiles in several lo- cations across the Hornsund fjord from 2015 to 2023. From 2016 onward dissolved oxygen and turbidity data are available for the majority of casts. The dataset contributes to the so far infrequent observations especially in spring and autumn and extends the observations typically concentrated in the central fjord to the areas adjacent to the tidewater glaciers. Because sediment discharge from glaciers and land is an inseparable part of the glacier-ocean interactions, the suspended sediment concentration in the water column as well as the daily sedimentation rate adjacent to the tidewater glaciers are monitored with regular water sampling and bottom-moored sediment traps. Here we present the planning and execution of the monitoring campaign from the collection of the data to the post-processing methods. All datasets are publicly available at the repositories referred to in the Data availability section of this manuscript.