Surface circulation of the eastern Mediterranean Levantine basin: Insights from analyzing 14 years of satellite altimetry data

Abstract

[1] The complex multiscale system circulation of the Levantine Eastern Mediterranean (EM) basin is analyzed by applying various spatiotemporal statistical methods on the AVISO 14 years (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006) data set of satellite altimetry sea level anomalies. The Rossby deformation radius at the EM is at the order of 10 km, which is also the horizontal satellite resolution. Therefore, the geostrophic currents, derived from the satellite altimetry measurements, represent well the basin and the mesoscale circulations. The long-term averaged mean dynamic topography (MDT) is found to capture the different eddy activity regions in the EM; however, these regions are highly turbulent. The instantaneous currents in these regions can be different from the MDT-derived currents, by the same order of magnitude. Furthermore, the turbulence intensity appears to be nonperiodic, despite of the seasonal and long-term steric periodic variability. Because these eddies interact with the basin circulation flow, they modify it continuously. The major exception of this sporadic behavior is the Ierapetra eddy, southeast of Crete. It appears to be forced by shear of the summer Etesian winds, created when the Crete mountain ridges block these winds and cause a funneling effect. It has a persistent seasonal signature that dominates the variance of the entire Levantine basin.

Neolithic Voyages to Cyprus: Wind Patterns, Routes, and Mechanisms

“…The velocity of this anticlockwise current is between 15 and 20 cm/sec (0.3-0.4 knots), strengthening to 25 cm/sec (0.5 knots) in the Cyprus-Syria passage and in the Cilician and Antalya basins (Gerin et al 2009;Menna et al 2012:50). Currents derived from altimeter data (Amitai et al 2010) also suggest that the surface currents are overall weaker than 25 cm/sec (0.5 knots). It is however underlined that "this complex circulation cannot be simply characterized in terms of timeaverages or of seasonal variability" (Menna et al 2012:55).…”

“…Therefore, Atlantic water enters the western Mediterranean through the Strait of Gibraltar on the surface layer, and flows towards the eastern Mediterranean in a cyclonic (anticlockwise) manner (Alhammoud et al 2005;Hamad et al 2006;Nielsen 1912). The prevalent current around Cyprus, between the island and the Levant coast to the east and north, is also anticlockwise, but varies in time due to the presence of mesoscale eddies (eddies with a spatial scale of few tens of nm) and meandering of the currents (Amitai et al 2010;Hamad et al 2006). Some of these eddies are semi-permanent and can affect the crossing from the mainland to Cyprus, such as the "Shikmona" eddy (Amitai et al 2010;Ayoub et al 1998).…”

“…The prevalent current around Cyprus, between the island and the Levant coast to the east and north, is also anticlockwise, but varies in time due to the presence of mesoscale eddies (eddies with a spatial scale of few tens of nm) and meandering of the currents (Amitai et al 2010;Hamad et al 2006). Some of these eddies are semi-permanent and can affect the crossing from the mainland to Cyprus, such as the "Shikmona" eddy (Amitai et al 2010;Ayoub et al 1998). However, for discussion in the present paper, we note that for the most part, surface currents are relatively weak and are not expected to significantly affect sea crossing.…”

“…Wind stress and thermohaline fluxes produce a complex and dynamic velocity field that varies on a wide range of temporal and spatial scales. We review here the important aspects of the surface currents in the Levantine basin, based on current measurements, surface drifters (Gerin et al 2009;Menna et al 2012;Poulain et al 2012), currents calculated based on satellite data (Amitai et al 2010;Poulain et al 2012), and numerical models (Hamad et al 2006).…”

Oil spill contamination probability in the southeastern Levantine basin

“…The meandering of the along-slope current has been shown to be related to the exchange of coastal and deep water in either the detachment of the anticyclonic Shikmona eddy near Haifa bay (Gertman et al, 2010) or the formation of filaments of coastal waters intruding to deep waters (Efrati et al, 2013). Beyond the slope area, the flow is not characterized by a single permanent feature, but rather by an area populated with dynamic meso-scale eddies (Amitai et al, 2010). The circulation in this area, on average, is anticyclonic, but can be locally interrupted by cyclonic mesoscale patterns.…”