around 48 hours with drifting sediment traps, pumping devices and measurements (using bottles, camera, nets) aimed at quantifying primary, regenerated and export productions of N, C, Si and S, and at getting some basic information concerning zooplankton and secondary production (this last point being presently a weakness of the proposal).
PARTICIPANTS
In France, the physical oceanography component of the project will be mostly carried by scientists at LPO/IFREMER (Brest), LODYC (Paris), LEGOS (Toulouse), French Met Office (Toulouse), LPCM (Villefranche), EpSHOM (Brest) and CELENV (Toulouse). The major laboratories involved in the biogeochemical component are LPCM and LOBE (Villefranche), COM and LMM (Marseilles), IUEM (Brest), SHOM (Brest), LEGOS (Toulouse) and LODYC (Paris). The project will establish links with MERCATOR, the real-time operational oceanography project, and with CLIPPER, a French WOCE program aimed at simulating the global circulation of the Atlantic Ocean in an eddy resolving (1/6°) model.
In the UK, two projects have being proposed and are at different stages of planning. The Southampton Oceanographic Center plans to contribute with a profiling mooring (first in late 1999-early 2000; then in late 2000-autumn 2001) and with tritium/helium surveys. An other project is being proposed by the University of East Anglia and collaborative institutions, which will include release of a tracer SF6 and the investigation of its later distribution from the French POMME cruises and from a dedicated process study cruise.
Other collaborations are sought and welcome.
Legends for figures
Figure 1. Subduction of modal water in the North-East Atlantic. The shaded area represents the low potential vorticity water subducted under the seasonal pycnocline. The dashed line is the maximum depth of the winter mixed layer. (From Paillet and Arhan, 1996a).
Figure 2. The POMME experiment. Top : the dased line is the subduction line. The symbols illustrate the mooring positions. Middle : CTD survey to be performed during the first leg of the winter and spring cruises. Bottom : more detailed long stations are to be performed during the second leg, for biogeochemical observations.
Figure 3. The position of the moorings, with tomography sources and recievers. S1 and S2 will have the autonomous SARA receivers; JH1 and JH2 will be the new Janus Helmholtz sources at 400 and 250 Hz, while E will be a erato transceiver (WRC). All those moorings will have various other instrumentation, including upward looking ADCP on S1, E, and S2, currentmeters, temperature and salinity sensors, and sound sources for the rafos-type vcm floats. The nominal separation of the moorings vary from 300 to 600 km.
