CHARACTERISTICS AND CIRCULATION OF THE SURFACE AND INTERMEDIATE WATERMASSES OFF ALGERIA

During the Mediprod-5 experiment, conducted off Algeria between simila r to 0 and 5 degrees E in 1986-1987, similar to 100 CTD casts were mad e in May-June 1986 down to similar to 800 decibars. Their analysis is supported by results from current meters set in place for similar to 9 months in the same area. The flow of Modified Atlantic Water (MAW) of f Algeria, namely the Algerian Current, was initially (near 0-2 degree s E) structured as a narrow (similar to 30 km) and deep (similar to 40 0 m) coastal vein (transport similar to 1.7 Sv). It became wider and t hinner to the east, with its core slightly detached from the coast. Th is current was first expected to generate coastal anticyclonic eddies and second to interact strongly with open sea anticyclonic eddies. Two such mesoscale eddies were sampled. Geostrophic calculations and drif ting buoy trajectories dearly show that the whole Algerian Current was deflected seawards due to interaction with an open sea eddy. Spatial gradients of the temperature minimum of the Winter Intermediate Water (WIW), and of the temperature and salinity maxima of the Levantine Int ermediate Water (LIW), are consistent with historical data. They indic ate that both waters how eastwards along the Algerian continental slop e. These data sets allow completion of our circulation diagrams. In th e eastern Alboran Sea, the old MAW, the WIW and the LIW, flowing from the north along the Spanish continental slope, more or less collide wi th the MAW that has recently entered through the Strait of Gibraltar. Therefore, all or a part of them is entrained off Algeria and, as a wh ole, they roughly flow cyclonically along the continental slope in mos t of the western Mediterranean Sea. The distribution of these water ma sses in the Algerian Basin is strongly dependent on the Algerian Curre nt and on the various kinds of mesoscale anticyclonic eddies encounter ed there.