Mediterranean anomaly map of Sea Surface Salinity

'''DEFINITION''' Mediterranean Sea Surface Salinity is the salinity of the 1st model layer (depth 1m). The map of the 2019 Sea Surface Salinity anomaly is evaluated with respect to the 1993 – 2014 climatology in the Mediterranean Sea and is based on the Mediterranean Sea Reanalysis product (MEDSEA_MULTIYEAR_PHY_006_004, Escudier et al., 2010). A positive anomaly means that the sea surface salinity is saltier than the reference, whereas a negative anomaly indicates a fresher sea surface salinity with respect to the reference one.

'''CONTEXT''' The Mediterranean Sea is a semi-enclosed sea connected to the Atlantic Ocean to the west through the Gibraltar Strait and connected to the Black Sea to the east through the Marmara Sea and the Dardanelles strait. Water introduced into the basin through the Gibraltar and Dardanelles Straits and the rivers is balanced by water loss at the surface due to excess evaporation with respect to precipitation and runoff. The salinity that results from this water balance is characterized by surface values at the Gibraltar inflow ~36.5 PSU and values ~ 39 PSU in the Levantine basin. In this context, the mean annual surface salinity anomaly, evaluated with respect to a reference period (1993-2014), is provided to monitor its horizontal variability. The monitoring of the surface salinity anomaly can provide indication on the salinification occurring in the Mediterranean Sea and on the mostly impacted areas. The scientific context of this OMI is proposed in Mulet et al., (2018).

'''CMEMS KEY FINDINGS''' In 2019, higher than average values are found almost everywhere in the Mediterranean Sea, thus confirming the basin salinification shown in previous studies (Rixen et al., 2005; Vargas-Yanez et al. 2010; Borghini et al. 2014; Schroeder et al. 2016; Skliris et al. 2018 among the others). Maximum values are evident in the north Adriatic Sea and Aegean Sea, while lower than average values mainly occur in the Southern Central basin, Algerian basin, in the north Aegean Sea and in front of the Po river in the North Adriatic Sea. The Ionian and north Aegean Sea negative salinity anomalies were already evident in the 2018 sea surface salinity anomaly map. Such anomalies occurred in the 90’s as precursor signals of the anticyclonic change of the basin scale circulation in the Ionian Sea (Pinardi et al., 2015).