Hydrography and circulation west of Sardinia in June 2014

Knoll, Michaela, Borrione, Ines, Fiekas, Heinz-Volker, Funk, Andreas, Hemming, Michael P., Kaiser, Jan, Onken, Reiner, Queste, Bastien and Russo, Aniello (2017) Hydrography and circulation west of Sardinia in June 2014. Ocean Science, 13 (6). pp. 889-904. ISSN 1812-0784

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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 vessel-mounted 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<σΘ/(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.

    Item Type: Article
    Faculty \ School: Faculty of Science > School of Environmental Sciences
    University of East Anglia > Faculty of Science > Research Groups > Atmospheric Chemistry
    University of East Anglia > Faculty of Science > Research Groups > Climate, Ocean and Atmospheric Sciences
    University of East Anglia > Faculty of Science > Research Groups > Marine and Atmospheric Sciences
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    Depositing User: Pure Connector
    Date Deposited: 15 Nov 2017 06:06
    Last Modified: 25 Jul 2018 14:17
    URI: https://ueaeprints.uea.ac.uk/id/eprint/65448
    DOI: 10.5194/os-13-889-2017

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