Extreme Western Intermediate Water formation in winter 2010

Vargas‐Yáñez, Manuel; Zunino, Patricia; Schröeder, Katrin; López-Jurado, José Luís; Plaza, Francisco; Serra, Mariano; Castro, C.; García-Martínez, M.C.; Moyá, Francina; Salat, Jordi

doi:10.1016/j.jmarsys.2012.05.010

Cited by 44 publications

(46 citation statements)

References 18 publications

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“…Several repeat CTD stations showed that the eddy moved northward during the experiment with a mean velocity of about 0.014 m s −1 . The observed core values of the eddy (Table 2) were in agreement with previous observations of WIW in the northern WMED (Vargas-Yáñez et al, 2012;Juza et al, 2013), the Alboran Sea (Allen et al, 2008), and the Algerian Basin (Benzohra and Millot, 1995) (Table 2), but to our knowledge no WIW eddy with such low temperatures and salinities has been documented in the Sardinian Sea in the past.…”

Section: Wiw/tmlsupporting

confidence: 91%

“…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. Values of 12.35 • C and 38.3 are observed in the zone of formation (Benzohra and Millot, 1995;Vargas-Yáñez et al, 2012). WIW mainly follows the path of MAW westward along the European continental slope and across the Algerian Basin (Millot, 1999;Benzohra and Millot, 1995).…”

Section: Introductionmentioning

confidence: 96%

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Hydrography and circulation west of Sardinia in June 2014

Knoll¹,

Borrione

Fiekas³

et al. 2017

Ocean Sci.

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Abstract. In the frame of the REP14-MED sea trial in June 2014, the hydrography and circulation west of Sardinia, observed by means of gliders, shipborne CTD (conductivity, temperature, depth) instruments, towed devices, and vesselmounted ADCPs (acoustic doppler current profilers), are presented and compared with previous knowledge. So far, the circulation is not well-known in this area, and the hydrography is subject to long-term changes. Potential temperature, salinity, and potential density ranges as well as core values of the observed water masses were determined. Modified Atlantic Water (MAW), with potential density anomalies below 28.72 kg m −3 , showed a salinity minimum of 37.93 at 50 dbar. Levantine Intermediate Water (LIW), with a salinity maximum of about 38.70 at 400 dbar, was observed within a range of 28.72<σ /(kg m −3 ) < 29.10. MAW and LIW showed slightly higher salinities than previous investigations. During the trial, LIW covered the whole area from the Sardinian shelf to 7 • 15 E. Only north of 40 • N was it tied to the continental slope. Within the MAW, a cold and saline anticyclonic eddy was observed in the southern trial area. The strongest variability in temperature and salinity appeared around this eddy, and in the southwestern part of the domain, where unusually low saline surface water entered the area towards the end of the experiment. An anticyclonic eddy of Winter Intermediate Water was recorded moving northward at 0.014 m s −1 . Geostrophic currents and water mass transports calculated across zonal and meridional transects showed a good agreement with vessel-mounted ADCP measurements. Within the MAW, northward currents were observed over the shelf and offshore, while a southward transport of about 1.5 Sv occurred over the slope. A net northward transport of 0.38 Sv across the southern transect decreased to zero in the north. Within the LIW, northward transports of 0.6 Sv across the southern transects were mainly observed offshore, and decreased to 0.3 Sv in the north where they were primarily located over the slope. This presentation of the REP14-MED observations helps to further understand the long-term evolution of hydrography and circulation in the Western Mediterranean, where considerable changes occurred after the Eastern Mediterranean Transient and the Western Mediterranean Transition.

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Section: Wiw/tmlsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 96%

Hydrography and circulation west of Sardinia in June 2014

Knoll¹,

Borrione

Fiekas³

et al. 2017

Ocean Sci.

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“…Similar T/S hydrological signatures to the "coastal waters" described in this work (Figs. 10, 11) have been reported by Dufau-Julliand et al (2004) over the inner GoL shelf and by Vargas-Yáñez et al (2012) in coastal areas under the influence of the other major western Mediterranean river, the Ebro. The surface and shelf/coastal origin of this water mass was also evidenced by its high dissolved oxygen content and particle load (Fig.…”

Section: Mechanisms and Sources Implied In The Observed Particle Fluxesmentioning

confidence: 90%

Sediment transport along the Cap de Creus Canyon flank during a mild, wet winter

et al. 2013

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Cap de Creus Canyon (CCC) is known as a preferential conduit for particulate matter leaving the Gulf of Lion continental shelf towards the slope and the basin, particularly in winter when storms and dense shelf water cascading coalesce to enhance the seaward export of shelf waters. During the CASCADE (CAscading, Storm, Convection, Advection and Downwelling Events) cruise in March 2011, deployments of recording instruments within the canyon and vertical profiling of the water column properties were conducted to study with high spatial-temporal resolution the impact of such processes on particulate matter fluxes. In the context of the mild and wet 2010–2011 winter, no remarkable dense shelf water formation was observed. On the other hand, the experimental setup allowed for the study of the impact of E-SE storms on the hydrographical structure and the particulate matter fluxes in the CCC. The most remarkable feature in terms of sediment transport was a period of dominant E-SE winds from 12 to 16 March, including two moderate storms (maximum significant wave heights = 4.1–4.6 m). During this period, a plume of freshened, relatively cold and turbid water flowed at high speeds along the southern flank of the CCC in an approximate depth range of 150–350 m. The density of this water mass was lighter than the ambient water in the canyon, indicating that it did not cascade off-shelf and that it merely downwelled into the canyon forced by the strong cyclonic circulation induced over the shelf during the storms and by the subsequent accumulation of seawater along the coast. Suspended sediment load in this turbid intrusion recorded along the southern canyon flank oscillated between 10 and 50 mg L⁻¹, and maximum currents speeds reached values up to 90 cm s⁻¹. A rough estimation of 10⁵ tons of sediment was transported through the canyon along its southern wall during a 3-day-long period of storm-induced downwelling. Following the veering of the wind direction (from SE to NW) on 16 March, downwelling ceased, currents inside the canyon reversed from down- to up-canyon, and the turbid shelf plume was evacuated from the canyon, most probably flowing along the southern canyon flank and being entrained by the general SW circulation after leaving the canyon confinement. This study highlights that remarkable sediment transport occurs in the CCC, and particularly along its southern flank, even during mild and wet winters, in absence of cascading and under limited external forcing. The sediment transport associated with eastern storms like the ones described in this paper tends to enter the canyon by its downstream flank, partially affecting the canyon head region. Sediment transport during these events is not constrained near the seafloor but distributed in a depth range of 200–300 m above the bottom. Our paper broadens the understanding of the complex set of atmosphere-driven sediment transport processes acting in this highly dynamic area of the northwestern Mediterranean Sea

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“…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].…”

Section: Eddies Characterization and Classification 321 Anticyclonmentioning

confidence: 99%

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

et al. 2016

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Since 2010, an intense effort in the collection of in situ observations has been carried out in the northwestern Mediterranean Sea thanks to gliders, profiling floats, regular cruises, and mooring lines. This integrated observing system enabled a year‐to‐year monitoring of the deep waters formation that occurred in the Gulf of Lions area during four consecutive winters (2010–2013). Vortical structures remnant of wintertime deep vertical mixing events were regularly sampled by the different observing platforms. These are Submesoscale Coherent Vortices (SCVs) characterized by a small radius (∼5–8 km), strong depth‐intensified orbital velocities (∼10–20 cm s−1) with often a weak surface signature, high Rossby (∼0.5) and Burger numbers O(0.5–1). Anticyclones transport convected waters resulting from intermediate (∼300 m) to deep (∼2000 m) vertical mixing. Cyclones are characterized by a 500–1000 m thick layer of weakly stratified deep waters (or bottom waters that cascaded from the shelf of the Gulf of Lions in 2012) extending down to the bottom of the ocean at ∼2500 m. The formation of cyclonic eddies seems to be favored by bottom‐reaching convection occurring during the study period or cascading events reaching the abyssal plain. We confirm the prominent role of anticyclonic SCVs and shed light on the important role of cyclonic SCVs in the spreading of a significant amount (∼30%) of the newly formed deep waters away from the winter mixing areas. Since they can survive until the following winter, they can potentially have a great impact on the mixed layer deepening through a local preconditioning effect.

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Extreme Western Intermediate Water formation in winter 2010

Cited by 44 publications

References 18 publications

Hydrography and circulation west of Sardinia in June 2014

Hydrography and circulation west of Sardinia in June 2014

Sediment transport along the Cap de Creus Canyon flank during a mild, wet winter

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

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