Origin and pathways of Winter Intermediate Water in the Northwestern Mediterranean Sea using observations and numerical simulation

Abstract

The study of water masses worldwide (their formation, spreading, mixing, and impact on general circulation) is essential for a better understanding of the ocean circulation and variability. In this paper, the formation and main pathways of Winter Intermediate Water (WIW) in the Northwestern Mediterranean Sea (NWMED) are investigated during the winter‐spring 2011 using observations and numerical simulation. The main results show that the WIW, formed along the continental shelves of the Gulf of Lion and Balearic Sea, circulates southward following five preferential pathways depending on the WIW formation site location and the oceanic conditions. WIW joins the northeastern part of the Balearic Sea, or flows along the continental shelves until joining the Balearic Current (maximum of 0.33 Sv in early‐April) or further south until the Ibiza Channel entrance. Two additional trajectories, contributing to water mass exchanges with the southern part of the Western Mediterranean Sea, bring the WIW through the Ibiza and Mallorca Channels (maxima of 0.26 Sv in late‐March and 0.1 Sv in early‐April, respectively). The circulation of WIW over the NWMED at 50–200 m depth, its mixing and spreading over the Western Mediterranean Sea (reaching the south of the Balearic Islands, the Algero‐Provencal basin, the Ligurian and the Alboran Seas) suggest that the WIW may have an impact on the ocean circulation by eddy blocking effect, exchange of water masses between north and south subbasins of Western Mediterranean Sea through the Ibiza Channel or modification of the ocean stratification.

Scales and dynamics of Submesoscale Coherent Vortices formed by deep convection in the northwestern Mediterranean Sea

“…The WIW can also be formed on the continental shelves of the Gulf of Lions and the Balearic Sea [Vargas-Yañez et al, 2012;Juza et al, 2013].…”

From basin to sub-basin scale assessment and intercomparison of numerical simulations in the Western Mediterranean Sea

“…As highlighted by Heslop et al (2012), Juza et al (2013) and in Fig. 11a, the 504 observed T/S diagram reveals the typical water masses of the WMED (AW, LIW, WMDW) and the 505 presence of WIW in the Ibiza Channel at 50-200m (Fig.…”

“…11d). Juza et al (2013) have shown, using 506 a regional high-resolution simulation, that the main part of the WIW going through the Ibiza 507…”

Hydrography and circulation west of Sardinia in June 2014

“…Based on historical data, the mean potential temperature and salinity of the core in summer in the Sardinian Sea are 17.71 • C and 37.61 with a standard deviation of 2.87 • C and 0.33, respectively (Sparnocchia et al, 1994). WIW consists of cooled and homogenized MAW formed in winter during cold wind events in the northern WMED (Juza et al, 2013). It is characterized by local minima in potential temperature and salinity at about 150 to 200 m depth, with magnitudes depending on the formation conditions.…”

“…WIW mainly follows the path of MAW westward along the European continental slope and across the Algerian Basin (Millot, 1999;Benzohra and Millot, 1995). An additional pathway of WIW directly connecting the formation area to the Algerian Basin is expected to be induced by frontal eddies associated with the North Balearic Front (Millot, 1999;Fuda et al, 2000). This North Balearic Front separates the Atlantic Water reservoir in the south from the saltier and denser waters in the north (Olita et al, 2013).…”