Surface and Bottom Aggregated In Situ Temperature and Salinity Datasets for the Northwest Atlantic Ocean for 2000-2024

Data from multiple sources collected within the Northwest Atlantic (34°N-77°N to 45°N-63°W) of oceanographic temperature and salinity are standardized and aggregated into two depth bins: surface and bottom. Observations were compiled from differing instruments and deployment methods, including buoy, flowthrough, and vertical profiles, and subsequently separated into "profiles". Buoy data were separated into 1-hour temporal bins to create a quasi-profile. For data collected from a flowthrough system at a fixed intake depth (i.e., TSG), quasi-profiles were created through spatial binning. Data collected using flowthrough systems were put onto an 80x94 grid, and observations within each grid cell were averaged to create hourly spatial bins. Glider data from the World Ocean database were already split into individual profiles when downloaded. Finally, vertical profiles were extracted using the direction of observations (i.e., up or downcast) and a unique profile identifier, like a station ID or coordinates. Only upcasts were retained for further processing. We define the surface layer as the top mixed layer of water that interacts with the atmosphere, or the mixed layer. Not all data types (i.e. buoy and flowthrough) have a vertical component; therefore, a modeled product was used to aid in separating the surface signature in the data. GLobal Ocean ReanalYsis and Simulation project (GLORYS12V1) modeled climatological mixed layer depth was acquired from Copernicus Marine Service at a 0.083 degree spatial resolution (datasetID: cmems_mod_glo_phy_my_0.083deg-climatology_P1M-m). As mixed layer depths are highly variable, a climatological mixed layer depth was used in place of a daily mixed layer depth to standardize the surface bin temporally. Once observations were grouped into profiles, each profile was matched to a climatological mixed layer depth using a Euclidean distance nearest-neighbor search. The bottom layer is defined as water within 10 meters of the bathymetric bottom. For each profile, observations within the defined depth bin were averaged to created a single mean value. This dataset is a standardized, comprehensive dataset of in situ temperature and salinity observations for surface and bottom depths for the Northwest Atlantic.