Long term glider monitoring: the Ibiza Channel Endurance Line

thumbnail image - Long term glider monitoring: the Ibiza Channel Endurance Line
19 de febrero de 2014

The long term glider monitoring of the endurance line in the Ibiza Channel, a well established hot spot for biodiversity in the Mediterranean, continues in 2014 with a new glider mission. On 7th February 2014 a G2 Slocum Deep glider (operates to 1000 m depth) was launched and will spend the next month at sea, monitoring the channel. Data has been collected by gliders along this endurance line since 2011 and this will be our 19th successful deep glider mission in the channel.

In 2013, SOCIB gliders with in kind support from IMEDEA (CSIC-UIB), carried out over 242 mission days, covering 2,800 miles and collecting 4.578 vertical profiles of the ocean, from surface to 1,000 m depth. Data collected include physical (temperature, salinity and estimated integrated current) and biogeochemical data (oxygen and fluorescence), that are allowing us to better understand the state of ocean currents, the variability of the oceanic circulation, and the role of the ocean in climate and in seasonal atmospheric forecasting among other key topics for science and society. IMEDEA (CSIC-UIB) initiated glider activities in 2006 and since then, around 21,893 vertical profiles have been collected in the western Mediterranean.



The Ibiza Channel is a narrow (80 km) channel that lies between the mainland of Spain and Ibiza, where more saline waters from the north flow south and fresher waters from the south flow north. This exchange of waters is known to affect local ecosystems, for example the spawning grounds of Atlantic Bluefin Tuna (Alemany et al., 2010 ).

Data collected by our gliders, in combination with an earlier record of ships data from IEO (recently described in Balbín et al., 2013), has enabled us to establish the existence of a high frequency variability in the exchange of water masses through the channel (Heslop et al., 2012.). A variability at a weekly/monthly time scale that is of the same order as the seasonal variability established more than a decade ago, by this showing the importance of monitoring at small scales. In this manner gliders have shown themselves to be an ideal and complementary platform to ships for oceanographic research. Of particular importance is the gliders ability to operate under extreme atmosphere-ocean conditions, such as those occurring in Spain during January and February 2014, where explosive cyclogenesis (February 9-10 2014, with a sea level pressure decrease by 24 hPa or more in 24 hours) has affected the western Mediterranean. The data collected by gliders is unique in establishing a better understanding of atmosphere-ocean interactions under extreme events, when sea conditions make it difficult/impossible for research ships to operate.

The Ibiza channel Endurance line (including all the laboratory work, pressure chamber and at sea testing activities required for its maintenance) is a key component of SOCIB Glider Facility sustained activities (included in SOCIB Implementation Plan) with in kind support from IMEDEA (CSIC-UIB) and also with partial support from EU funded projects such as PERSEUS (http://www.perseus-net.eu),  MyOcean (http://www.myocean.eu), and JERICO (http://www.jerico-fp7.eu) -in this case,  also with specific participation in TNA glider activities-.


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