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Contents 1. Introduction 1.1. The overall functioning 1.2. The problems about the circulation 2. The data sets 2.1. The remotely sensed data sets 2.2. The in situ data sets 3. The circulation of the surface water 3.1. AW in the western basin 3.2. AW in the eastern basin 4. The circulation of the intermediate and deep waters 4.1.

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Molecular dynamics simulations of Li+BF4 - in liquid ethylene carbonate, propylene carbonate, and dimethyl carbonate at low concentration are reported. Structural, thermodynamical, and dynamical properties have been obtained at 323 and 348 K in ethylene carbonate, 298 and 323 K in propylene carbonate, and 298 K in dimethyl carbonate. The diffusion coefficient of the lithium cation is found to be very similar in the three solvents ((0.3−0.6) × 10-9 m2 s-1 in this temperature range). This behavior is linked to the structure of the first solvation shell, which contains four strongly bound solvent molecules in a tetrahedral arrangement in all three cases. No exchange of solvent molecules between the first and the second solvation shells of the lithium ion have been observed during the 100-ps simulations. In the three carbonates, the fluoroborate ion is bound to 19 or 20 solvent molecules in the first solvation shell, the coordination shell being much less structured than in the case of the lithium ion, and the diffusion coefficient exhibits a more significant solvent and temperature dependence.

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Two new parametrizations of a recent ab initio polarizable anisotropic site potential for water are presented. The new versions improve the description of the electrostatic interactions, add an explicit charge-transfer term, and use more accurate dispersion coefficients from the recent literature. To assess the merits of the new models, the potential energy surface of the dimer is analyzed and a comparison is made with 12 other polarizable potentials for water in the literature, most of them being currently used in computer simulation. The structure, energy, and harmonic intermolecular frequencies of the stationary points have been determined and compared with the best available ab initio calculations. The energy barriers and pathways for hydrogen atom interchange within the dimer are discussed. The second virial coefficient B(T) of steam between 373 and 973 K, including first-order quantum corrections, is reported. For all the models, the quantum corrections are found to be significant at the lowest temperatures, amounting to 10−15% at 373 K. Roughly 90% of the quantum corrections arise from the rotational degrees of freedom. Among the potentials considered, only those presented in the present work and a few others are really successful in reproducing the experimental results for B(T) in that temperature range.

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