ALBERT

Description: An experiment, carried out in the Middle Adriatic in late May 2017, documented the existence of a dense water dome in the area between the island of Blitvenica (close to the east coast) and the island of Jabuka (in the open sea). The yo-yo CTD measurements showed that the dome center was located at a distance of about 20 km from the coast while the vmADCP measurements revealed that the surface circulation around the dome was cyclonic. The temperature above the dome was slightly lower than farther off, as documented by in situ and remotely-sensed data. At the same time, a decrease of temperature close to the east coast was documented by bottom probes and satellite images. The meteorological data and modeling results showed that during the May 2017 experiment the northern winds prevailed, implying that the observations could be interpreted in terms of simultaneous occurrence of open-sea and coastal upwelling. With the aim of verifying the interpretation, a number of schematized numerical experiments were conducted. To begin with, the modelled wind fields were decomposed into the curl and curl-free components by using the Helmholtz-Hodge decomposition. Subsequently, the components were used to impose the forcing on the Adriatic model, assuming flat bottom and realistic bathymetry. The simulations showed that the wind curl was responsible for the occurrence of open-sea upwelling whereas the curl-free wind component supported the development of coastal upwelling.