Glider monitoring reveals high sub-seasonal variability at a key ‘choke' point in the thermohaline circulation of the Western Mediterranean

• Main Authors: Heslop, Emma, Ruiz, Simón, Allen, John T., López-Jurado, José Luis, Tintoré, Joaquín
• Format: Conference Object
• Language: English
• Published: European Geosciences Union 2013
• Subjects: Arctic; Drake Passage; Southern Ocean; North Atlantic
• Online Access: http://hdl.handle.net/10261/123218

Trabajo presentado en la EGU General Assemby 2013, celebrada del 7 al 12 de abril de 2013 en Viena (Austria) It is becoming increasingly important to understand sub-seasonal variability in our ocean circulation, in order to place historical observations in context and detect the signature of climatic oscillations and change, and to improve the biogeochemical modelling of our ocean system. Flow variability and dynamic processes at inter-basin ‘choke’ points in the circulation system, such as Drake Passage in the Southern Ocean and the Fram Straits between the Arctic Sea and the North Atlantic Ocean, have an influential role in the patterns of heat, salt and watermass exchange between ocean basins and are particularly important locations to monitor variability at a variety of scales. The Ibiza Channel in the Western Mediterranean is one such ‘choke’ point in the basin scale circulation of the Mediterranean Sea, where an important north south exchange of water masses is known to influence the spawning grounds of commercially important fish stocks. Here autonomous underwater gliders are proving particularly effective at capturing the signature of sub-seasonal variability and the dynamics of an sub-basin exchange, previously only monitored at a seasonal level through ships surveys or at a coarse resolution with sparse moorings. Here we show the results of monthly glider monitoring of the Ibiza Channel in 2011– 2012, although due to technical issues the glider timeseries is not continuous for the whole period, we are nevertheless able to see days-weeks variability in the transport of different watermasses, on a scale comparable to that of the previously identified seasonal cycle. With the high spatial and temporal resolution of glider data, potential ‘modes’ of circulation are also identified with the aim of simplifying the complex pattern of flows previously observed at this dynamically complex location. This high variability is placed in the context of historical observations from the Instituto Español de ...