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We present a new product composed of a set of thermohaline climatic indices from 1950 to 2015 for the Mediterranean Sea such as decadal temperature and salinity anomalies, their mean values over selected depths, decadal ocean heat and salt content anomalies at selected depth layers as well as their long time series. It is produced from a new high-resolution climatology of temperature and salinity on a 1=8 regular grid based on historical high-quality in situ observations. Ocean heat and salt content differences between 1980-2015 and 1950-1979 are compared for evaluation of the climate shift in the Mediterranean Sea. The two successive periods are chosen according to the standard WMO climate normals. The spatial patterns of heat and salt content shifts demonstrate that the climate changes differently in the several regions of the basin. Long time series of heat and salt content for the period 1950 to 2015 are also provided which indicate that in the Mediterranean Sea there is a net mean volume warming and salinification since 1950 that has accelerated during the last two decades. The time series also show that the ocean heat content seems to fluctuate on a cycle of about 40 years and seems to follow the Atlantic Multidecadal Oscillation climate cycle, indicating that the natural large-scale atmospheric variability could be superimposed onto the warming trend. This product is an observation-based estimation of the Mediterranean climatic indices. It relies solely on spatially interpolated data produced from in situ observations averaged over decades in order to smooth the decadal variability and reveal the long-term trends. It can provide a valuable contribution to the modellers' community, next to the satellite-based products, and serve as a baseline for the evaluation of climate-change model simulations, thus contributing to a better understanding of the complex response of the Mediterranean Sea to the ongoing global climate change. The product is available in netCDF at the following sources: annual and seasonal T =S anomalies (https://doi.org/10.5281/zenodo.1408832), annual and seasonal T =S vertical averaged anomalies (https://doi.org/10.5281/zenodo.1408929), annual and seasonal areal density of OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1408877), annual and seasonal linear trends of T =S, OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1408917), annual and seasonal time series of T =S, OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1411398), and differences of two 30-year averages of annual and seasonal T =S, OHC/OSC anomalies (https://doi.org/10.5281/zenodo.1408903). © Author(s) 2018.

The basic characteristics of a large multi-parameter ocean data base for the Mediterranean and the Black Sea are described. The data base has been developed through a close cooperation between National Oceanographic Data Centres (NODCs) of the IOC/UNESCO and specialized marine research institutes, within the framework of the MEDAR/MEDATLAS Concerted Action, supported by the European Union (EU). The data used in developing the data base have been collected by about 150 scientific laboratories from 33 countries and consist of vertical profiles of in-situ temperature, salinity and bio-chemical parameters. In all, the data base includes 285 879 qualified hydrographic stations of bathythermographs, thermistors, CTDs and bottle casts. As regards the studied regions, these data increase greatly (almost twice) the volume of the ocean data made available to the user community, compared to earlier initiatives. They are published on a set of four CDRoms, which include other products such as a Cruise Inventory, a Climatological Atlas of gridded numerical fields with vertical sections, maps (static and animated to illustrate the annual cycle), as well as, a selection and visualisation software. Although there are still some gaps before a complete data service can be provided, this important concerted action has contributed in developing data management standards and methods, in drawing attention to the necessity of acquiring professional data archiving systems and finally in increasing data and information circulation in the Mediterranean and the Black Sea.