The acoustic tomography approach provides an indirect measure of the temperature of an ocean volume. The technique provides an integrated measure of temperature along the sound propagation paths. The variety of paths between a transmitter and a receiver, as well as the large number of instruments deliver information on the variability of the thermal content of the insonified volume.

The European Union’s Copernicus-funded TRUSTED project (Towards Fiducial Reference Measurements of Sea-Surface Temperature by European Drifters) has deployed over 100 state of the art drifting buoys for improved validation of Sea Surface Temperature (SST) from the Sentinel-3 Sea and Land Surface Temperature Radiometers (SLSTR). These buoys are manufactured by NKE. The TRUSTED drifting buoys data and metadata are distributed in qualtity control NetCDF files, as a subset of DBCP drifting buoys GDAC (Global Data Assembly Centre). Coriolis DAC  (Data Assembly Centre) routinely collects, decodes, quality controls, preserves and distributes data and metadata as NetCDF-CF files. The TRUSTED buoys have specific features managed by Coriolis DAC python data processing chain: a high resolution temperature sensor in addition to the classic drifting buoy temperature sensor. The high sampling and high resolution observations are distributed in specific variables TEMP_HR, TEMP_HR_SPOT, TEMP_HR_XX (XX is the percentile sample).  

Advanced Along-Track Scanning Radiometer multimission data have been reprocessed to provide update retrievals of Sea Surface Temperature (SST) to produce the AATSR Reprocessing for Climate (ARC) dataset.

X : eXpendable; B : Bathy; T: Thermograph. Thermal profile measurement with real-time transmission

GOSUD aims at assembling in-situ observations of the world ocean surface collected by a variety of ships and at distributing quality controlled datasets.  At present time the variables considered by GOSUD are temperature and salinity. The GOSUD data are mostly collected using thermosalinographs (TSG) installed on research vessels, on commercial ships and in some cases on sailing exploration ships GOSUD manages both near-real time data and delayed mode (reprocessed) data.

Routine operation over a period shorter than 5 years (Enhanced Observation Period, EOP)

The RAFOS float technique (the reverse acronym of SOund Fixing And Ranging) is used to obtain sub-surface trajectories of floats by acoustic location. These floats are immersed at a constant depth and drift with the body of water in which they are immersed. The floats record the arrival time of the sound signals emitted by a network of fixed acoustic sources placed on moorings. They regularly come to the surface to transmit the data that they have recorded.

Measurements by drifting surface buoys. This system is a drifting mooring consisting of a surface buoy fastened to a floating anchor by a cable (trip line, buoy rope). It has to monitor as precisely as possible the water volume in which the floating anchor is immersed. The surface buoys are traced by Argos satellites.

The Mytilobs network, carried out by IFREMER (French Research Institute for Exploitation of the Sea), is a national network dedicated to building long-term physiological variations time series of blue mussels (Mytilus edulis), across a large spatial scale. This observation network, initially designed to survey production yields, also provides valuable data to track environmental variations of coastal ecosystems. Mussels exhibit high phenotypic plasticity in response to environmental variations. Collection of data describing phenotypic variations, over an extended period, reveals small-scale climate and habitat variations. With its broad deployment across time and space, the data produced under Mytilobs will be useful for the establishment of a baseline condition when studying the effect of a perturbation affecting an ecosystem’s functioning. Finally, the monitoring of mussel biometric traits and mortality was coupled with high-frequency measurements of salinity, temperature, and sea level, complementing this multi-layer observational framework.

The COriolis Ocean Dataset for Reanalysis (hereafter "CORA") product is a global dataset of in situ temperature and salinity measurements. The CORA observations comes from many different sources collected by Coriolis data centre in collaboration with the In Situ Thematic Centre of the Copernicus Marine Service (CMEMS INSTAC).  The observation integrated in the CORA product have been acquired both by autonomous platforms (Argo profilers, fixed moorings , gliders , drifters, sea mammals) , research or opportunity vessels (CTDs, XBTs, ferrybox).  From the near real time CMEMS In Situ Thematic Centre product validated on a daily and weekly basis for forecasting purposes, a scientifically validated product is created. It s a "reference product" updated on a yearly basis since 2007. This product has been controlled using an objective analysis (statistical tests) method and a visual quality control (QC). This QC procedure has been developed with the main objective to improve the quality of the dataset to the level required by the climate application and the physical ocean re-analysis activities. It provides T and S weekly gridded fields and individual profiles both on their original level with QC flags and interpolated level. The measured parameters, depending on the data source, are : temperature, salinity. The reference level of measurements is immersion (in meters) or pressure (in decibars).  CORA contains historical profiles extracted from the EN.4 global T&S dataset, World Ocean Atlas, SeaDataNet, ICES and other data aggregators . The last version of the CORA product are also available freely from the Copernicus WEB site :   - Global Ocean- CORA- In-situ Observations Yearly Delivery in Delayed Mode - Global Ocean- Delayed Mode gridded CORA- In-situ Observations objective analysis in Delayed Mode