Tilted convective plumes in numerical experiments

Achim Wirth (1) , Bernard Barnier (1)

1 LEGI - Laboratoire des Écoulements Géophysiques et Industriels [Grenoble]

The dynamics of a single convective plume in an isothermal ocean is investigated by numerically inte- grating the three dimensional Boussinesq equations. Our study emphasizes on the important consequences of a non-vanishing angle between the axis of rotation and the buoyancy force (gravity). Experiments are performed for four different values of the angle corresponding to open-ocean convection at latitude: 90° N, 60° N, 45° N and 0° N. We show that the horizontal component of the rotation vector leads to qualitative and quantitative changes in the convective dynamics of a single plume. Plume structures are aligned along the axis of rota- tion rather than the direction of gravity (tilted convection), the vertical velocity of the plume is reduced, and the mixing is enhanced by the horizontal component of the rotation vector. These results suggest that in future parametrisations of ocean convection the effect of the horizontal component of the rotation vector should be included.

Mots clés: Geophysical fluid dynamics; ocean convection; traditional approximation

Domaines: Océan, Atmosphère

Achim Wirth, Bernard Barnier. Tilted convective plumes in numerical experiments. Ocean Modelling, 2006, 12 (1), pp.101-111. ⟨10.1016/j.ocemod.2005.04.005⟩. ⟨hal-00546299⟩