A fjord dataset for multidisciplinary applications: Thirteen years of ocean observations in Sermilik Fjord, Southeast Greenland

Abstract. As global atmosphere and ocean temperatures rise and the Greenland Ice Sheet loses mass, the glacial fjords of Kalallit Nunaat/Greenland play an increasingly critical role in our climate system. Fjords are pathways for freshwater from ice melt to reach the ocean and for deep, warm, nutrient–rich ocean waters to reach marine–terminating glaciers, supporting abundant local ecosystems that Greenlanders rely upon. Research in Greenland fjords has become more interdisciplinary and more observations are being collected in fjords than in previous decades. However, there are few long–term (> 10 years) datasets available for single fjords. Additionally, observations in fjords in general are often spatially and temporally disjointed, utilize multiple observing tools, and are rarely provided in formats that are easily used across disciplines or audiences. We address this issue by providing standardized, gridded summer season hydrographic sections for Sermilik Fjord in Southeast Greenland, from 2009–2023. Gridded data facilitate the analysis of coherent spatial patterns across the fjord domain, and are a more accessible and intuitive data product compared to discrete profiles. We combined ship–based conductivity, temperature, and depth (CTD) profiles with helicopter–deployed eXpendable CTD (XCTD) profiles from the ice mélange region to create objectively mapped (or optimally interpolated) along–fjord sections of conservative temperature and absolute salinity. From the gridded data, we derived a summer season climatological mean and root mean square deviation, summarizing typical fjord conditions and highlighting regions of variability. This information can be used by model and laboratory studies, fjord intercomparison studies, biological and ecosystem studies in the fjord, and provides context for interpreting previous work. All original profile observations, gridded data, and climatological products are publicly available in netCDF format at Arctic Data Center and GitHub. The code used has also been made available to facilitate continued updates to the Sermilik Fjord gridded data product and applications to other fjord systems.