26 years of mooring data from Olympic Coast National Marine Sanctuary

Olympic Coast National Marine Sanctuary (OCNMS) off Washington State was designated by the National Oceanic and Atmospheric Administration (NOAA) in 1994 and is embedded in the northern California Current (NCC) system, which is affected by climate fluctuations such as marine heat waves, El Niño, hypoxia, ocean acidification, and changes in timing of the spring transition to upwelling conditions. There is a need to better understand the climatological conditions in the Sanctuary, especially considering the presence of four Coastal Treaty Tribes with treaty-protected rights to marine resources on the Olympic Coast. Oceanographic moorings at five cross-shelf lines along the Olympic Coast have measured surface and subsurface water properties from 2000 to present. Measurements focus on the summer upwelling season, when hydrographic conditions fluctuate on the time scale of local wind events and remotely-generated coastal trapped waves, and biogeochemical stressors like hypoxia and ocean acidification tend to worsen. Additionally, temperature sensors deployed at the Teahwhit Head site and, in more recent years, at the Makah Bay site in 42 meters water depth remain in the water throughout the year to measure winter temperatures. This article provides a description of the OCNMS mooring program and our efforts to combine 26 years of water temperature, salinity, dissolved oxygen, pressure, and velocity data into quality-controlled time series available via Zenodo at https://doi.org/10.5281/zenodo.19751759.