The northern Adriatic circulation regimes in the future winter climate
Dunic, Natalija ; Supic, Nastjenjka ; Sevault, Florence ; Vilibic, Ivica
Reliability of climate change projections in coastal and shallow seas may be largely influenced by complex air-ocean-land interactions, like in the northernmost shelf of the Mediterranean, the Northern Adriatic (NAd). However, classification of winter characteristics in the NAd may be simplified following the observed cross-basin bottom density distributions. Two main types of winter circulation occur: (i) type A, when the basin is strongly affected by the freshwater load and (ii) type B, in which the dense water formation is occurring. Neutral winter circulation type with characteristics between types A and B is called type C. This paper evaluates a usage of such a classification in climate models, defines the best proxy index for the winter NAd characteristics and then quantifies winter regimes in the future climate. The latter is assessed by regional coupled atmosphere-ocean model CNRM-RCSM4 for three different scenarios. Acknowledging an offset in density differences, the historical climate run perfectly fits the observations. The number of type C circulation, i.e. with low cross-basin density differences, is projected to increase in the future climate, in particular in RCP4.5 scenario. The number of type A circulation is showing a decrease in all climate scenarios, while type B circulation is decreasing in RCP4.5 and RCP8.5 scenarios. As two main circulation types are conjoined with large differences in biogeochemical properties and fish stocks, these projected changes may have a substantial impact to the future productivity of this least oligotrophic basin in the Eastern Mediterranean.</p>
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