The Mediterranean, a major research laboratory for Global warming in need of a GO-SHIP program
17 June 2011, CIESM News

The Mediterranean Sea strongly affects the climate of the surrounding lands. To define its impact and interaction with atmospheric forcing, basin-wide repeat surveys of this sea are of primary importance. In this context the Mediterranean Science Commission (CIESM) invited 17 international scientists (1), all experts of the region, to a brainstorming Workshop in Supetar, on the island of Brac, Croatia, from 11 to 14 May 2011 where they designed a Med SHIP program, and planed repeat basin-wide hydrographic surveys for climatic studies in the Mediterranean Sea.

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One of the main scientific challenges currently ahead is to understand long-term variability and climate change issues, such as trends in temperature, sea level rise and occurrence of high impact extreme weather events. The Mediterranean Sea - this miniature ocean with a complicated topography - is very appropriate for studying some processes important for general oceanic and climatic research. Composed of several sub-basins separated by straits and channels of different depths, this sea is very sensitive to large atmospheric changes. Its complex morphology contributes to the predominance of mesoscale features such as 50 - 100 km gyres and eddies that modify and interact with the basin-wide water circulation. In the past two decades, dense water formation linked to cold winter episodes has been observed both through cascading along canyons and through the open-ocean convection reaching and spreading over the deep layer of the Mediterranean. The inflowing fresher Atlantic Water and outflowing saltier Mediterranean waters at the Strait of Gibraltar further influence the dynamics of bottom waters.

Studying the Mediterranean general circulation and its interannual and decadal variability is essential to get insight into the global climate impact at the regional and global scales. In order to document the changes in the basin hydrology and biogeochemistry, many technological and innovative tools are nowadays available to scientists and at work in various national/regional programs: CTDs and different types of sensors deployed during oceanographic campaigns, gliders, floats, moorings, satellites, etc. What is missing is a single international platform that would, as in the case of GO-SHIP (2) (http://www.go-ship.org/), enable the integration of data obtained by different measurement techniques and distinct national/international campaigns. There is also a need to exchange on a permanent basis information on planned national cruises in order to avoid duplications and to develop scientific syntheses and interpretation of hydrographic data, in partnership with global research programs.

To monitor variability in space and time, the design of continuous coordinated repeat basin-wide hydrographic surveys in place for at least the next 10 years was discussed during the workshop with strong recommendations that a future Med SHIP program should inter alia optimize national shiptime resources, enable merging and interpreting collected data at international level, define priorities in training, capacity building with a particular focus on developing countries so as to enhance cooperation and facilitate the exchange and sharing of data between northern and southern countries.

To implement a GO-SHIP like program in the region, some recommendations were adopted which take into account the specificity of the Mediterranean. To obtain a synoptic view of Mediterranean hydrology, different surveys need to be carried out, including:
          o High-frequency lines (3 years), generally North-South lines and low-frequency lines (6 years) along an East-West hydrographic transect along the longitudinal axis of the Mediterranean;
          o High frequency surveys using different platforms (ships and gliders mostly) at sub-basin and mesoscale in order to follow the variability of structures/processes that are influencing the basin scale circulation. To document and understand the water property distributions, their changes, and drivers including physical and biogeochemical properties, the survey shall consider relevant key areas.

Download CIESM Workshop Monograph n43

(1) Participating scientists invited by CIESM: Marta Álvarez, Giuseppe Civitarese, Miroslav Gacic (Chair, CIESM Committee on Physics and Climate of the Ocean), Mokhtar Guerfi, Daniel Hayes, Nurit Kress, Zivana Nincević, Piero Lionello, Emin Ozsoy, Vangelis Papathanassiou, Michel Rixen, Mohammed Said, Katrin Schroeder, Toste Tanhua, Maciej Telszewski, Isabelle Taupier-Letage and Joaquín Tintoré.
(2) GO-SHIP: The Global Ocean Ship-based Hydrographic Investigations Program  brings together scientists with interests in physical oceanography, the carbon cycle, marine biogeochemistry and ecosystems, and other users and collectors of ocean interior data to develop a sustained global network of hydrographic sections as part of the Global Ocean / Climate Observing System.

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Further info:

CIESM, the Mediterranean Science Commission, is supported by 22 Member Governments to promote international research in the Mediterranean and Black Seas. The Commission covers a broad spectrum of marine disciplines, relying on a pool of vast human resources: over 4,000 marine scientists from some 550 research institutes in more than 30 countries. On this basis, CIESM produces authoritative, impartial reports on the status and trends of Mediterranean marine systems, together with sharp recommendations on priorities for action, research and development on a large range of sensitive issues concerning the whole Mediterranean Basin.

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