Interannual Variations of Surface Currents and Transports in the Sicily Channel Derived From Coastal Altimetry

Fatma Jebri, Bruno Zakardjian, Florence Birol, Jérôme Bouffard, Loïc Jullion, Cherif Sammari
2017 Journal of Geophysical Research - Oceans  
A 20 year coastal altimetry data set (X-TRACK) is used, for the first time, to gain insight into the 10 long-term interannual variations of the surface circulation in the Sicily Channel. First, a spectral along with a 11 time/space diagram analysis are applied to the monthly means. They reveal a regionally coherent current 12 patterns from track to track with a marked interannual variability that is unequally shared between the 13 Atlantic Tunisian Current and Atlantic Ionian Stream inflows in
more » ... he Sicily Channel and the Bifurcation Tyrrhe-14 nian Current outflow northeast of Sicily. Second, an empirical altimetry-based transport-like technique is 15 proposed to quantify volume budgets inside the closed boxes formed by the crossing of the altimetry tracks 16 and coastlines over the study area. A set of hydrographic measurements is used to validate the method. 17 The inferred altimetry transports give a well-balanced mean eastward Atlantic Waters baroclinic flow of 0.4 18 Sv and standard deviations of 0.2 Sv on a yearly basis throughout the Sicily Channel and toward the Ionian 19 Sea, which is fairly coherent with those found in the literature. Furthermore, the analysis allows to quantify 20 the intrusions of Atlantic Waters over the Tunisian Shelf (0.12 6 0.1 Sv) and highlights two main modes of 21 variability of the main surface waters path over the Sicily Channel through the Bifurcation Atlantic Tunisian 22 Current and Atlantic Ionian Stream systems. Some physical mechanisms are finally discussed with regards 23 to changes in the observed currents and transports. 24 25 26 27 28
doi:10.1002/2017jc012836 fatcat:sarjtigebjcxljgyzawp6hiisi