The dynamical role of upper layer salinity in the Mediterranean Sea

Abstract

Abstract. The Mediterranean Sea (MED) is a semi-enclosed basin with an excess amount of evaporation compared to the water influx through precipitation at the surface and river runoff on the land boundaries. The deficit in the water budget is balanced by the inflow in the Strait of Gibraltar and Turkish Straits System connecting the Mediterranean with the less saline Atlantic Ocean and the Black Sea, respectively. There is evidence that the Mediterranean region is a hotspot in a warming climate, which will possibly change the water cycle significantly, but with large uncertainties. Therefore, it is inevitable to monitor the evolution of the essential ocean variables (EOVs) to respond to the associated risks and mitigate the related problems. In this work, we evaluate the evolution of the salinity content and anomaly between 0–300 m in the Mediterranean Sea during the last decades using the Copernicus Marine Service reanalysis and in situ objective analysis products. The results show an increasing mean salinity with a stronger trend in the eastern Mediterranean (EMED) basin. The spread of the products implies a larger variability in the western Mediterranean (WMED) basin, while the standard deviation is lower in the eastern side, especially in the Ionian and the Levantine basins.