On the Ionian thermohaline properties and circulation in 2010-2013 as measured by Argo floats

Abstract

       From all available Argo floats and altimetry data, the surface, intermediate (350 m depth) and deep (1000 m) circulation patterns in the Ionian Sea were analysed in detail for four consecutive years (2010, 2011, 2012 and 2013). In addition, thermohaline properties from float measurements were described and compared considering among all, the Dense Water Overflow from the Adriatic, particularly the one due to the strong winter air-sea heat loss in 2012. In the flow field, energetic closed circulation structures with the spatial scale of about 100 km were present during the entire study period. More specifically, the Pelops Gyre is observed from the surface down to more than 1000 m depth. A multi-lobe anticyclonic feature in the centre of the Ionian basin located to the north of the Mid Ionian Jet was also well evident in the same depth interval. The sub-basin-wide cyclonic circulation in the northern Ionian was clearly documented only in the close vicinity of the basin flanks at all the three levels. The most prominent signal of the Adriatic Dense Water (AdDW) was evidenced at about 1000 m depth in the northwestern portion of the basin in late spring 2012. Afterwards, very likely the AdDW progressively sank along its way southward and its signal was not recorded anymore because of the limited range of the float profiles (max 2000 m).