The oceanic tides in the South Atlantic Ocean

The finite element ocean tide model of Le\udProvost and Vincent (1986) has been applied to the simulation of the M₂\udand K₁ components over the South Atlantic Ocean. The discretisation\udof the domain, of the order of 200 km over the deep ocean, is refined down to 15\udkm along the coasts, such refinement enables wave propagation and damping over\udthe continental shelves to be correctly solved. The marine boundary conditions,\udfrom Dakar to Natal, through the Drake passage and from South Africa to\udAntarctica, are deduced from in situ data and from Schwiderski's solution and\udthen optimised following a procedure previously developed by the authors. The\udsolutions presented are in very good agreement with in situ data: the root mean\udsquare deviations from a standard subset of 13 pelagic stations are 1.4 cm for M₂\udand 0.45 cm for K₁, which is significantly better overall than\udsolutions published to date in the literature. Zooms of the M₂\udsolution are presented for the Falkland Archipelago, the Weddell Sea and the\udPatagonian Shelf. The first zoom allows detailing of the tidal structure around\udthe Falklands and its interpretation in terms of a stationary trapped Kelvin\udwave system. The second zoom, over the Weddell Sea, reveals for the first time\udwhat must be the tidal signal under the permanent ice shelf and gives a solution\udover that sea which is generally in agreement with observations. The third zoom\udis over the complex Patagonian Shelf. This zoom illustrates the ability of the\udmodel to simulate the tides, even over this area, with a surprising level of\udrealism, following purely hydrodynamic modelling procedures, within a global\udocean tide model. Maps of maximum associated tidal currents are also given, as a\udfirst illustration of a by-product of these simulations