Long-term mooring observations of full depth water column structure spanning 17 months, collected in a temperate shelf sea (Celtic Sea).

Data presented here were collected as part of the UK Shelf Sea Biogeochemistry project at a site in the central Celtic Sea, at a nominal location of 49.32N and -8.49E, in a mean water depth of 145.4 m. The study site was chosen to portray the general characteristics of a seasonally stratifying shelf sea, and was therefore located well away from any topographic features (such as sea mounts or the continental shelf edge) and tidal mixing fronts. Here, five consecutive deployments of a temperature-salinity (TS) chain mooring led to a continuous time series of full depth water column structure spanning 17 months from March 2014 to July 2015.