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| Reinaud, Jean N.; Carton, Xavier. |
| We investigate numerically the nonlinear interactions between hetons. Hetons are baroclinic structures consisting of two vortices of opposite sign lying at different depths. Hetons are long-lived. They most often translate (they can sometimes rotate) and therefore they can noticeably contribute to the transport of scalar properties in the oceans. Heton interactions can interrupt this translation and thus this transport, by inducing a reconfiguration of interacting hetons into more complex baroclinic multipoles. More specifically, we study here the general case of two hetons, which collide with an offset between their translation axes. For this purpose, we use the point vortex theory, the ellipsoidal vortex model and direct simulations in the... |
| Tipo: Text |
Palavras-chave: Baroclinic flows; Geophysical and geological flows; Quasi-geostrophic flows. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00333/44401/44157.pdf |
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| Menesguen, Claire; Mcwilliams, J.c.; Molemaker, M. Jeroen. |
| Oceanic large- and meso-scale flows are nearly balanced in forces between Earth’s rotation and density stratification effects (i.e. geostrophic, hydrostatic balance associated with small Rossby and Froude numbers). In this regime advective cross-scale interactions mostly drive energy toward larger scales (i.e. inverse cascade). However, viscous energy dissipation occurs at small scales. So how does the energy reservoir at larger scales leak toward small-scale dissipation to arrive at climate equilibrium? Here we solve the linear instability problem of a balanced flow in a rotating and continuously stratified fluid far away from any boundaries (i.e. an interior jet). The basic flow is unstable not only to geostrophic baroclinic and barotropic instabilities,... |
| Tipo: Text |
Palavras-chave: Baroclinic flows; Critical layers; Stratified flows. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00128/23906/21847.pdf |
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| Wang, Peng; Mcwilliams, James C.; Menesguen, Claire. |
| The linear instability of several rotating, stably stratified, interior vertical shear flows (U) over bar (z) is calculated in Boussinesq equations. Two types of baroclinic, ageostrophic instability, AI1 and AI2, are found in odd-symmetric (U) over bar (z) for intermediate Rossby number (R-0). AI1 has zero frequency; it appears in a continuous transformation of the unstable mode properties between classic baroclinic instability (BCI) and centrifugal instability (CI). It begins to occur at intermediate R-0 values and horizontal wavenumbers (k, l) that are far from l = 0 or k = 0, where the growth rate of BCI or CI is the strongest. AI1 grows by drawing kinetic energy from the mean flow, and the perturbation converts kinetic energy to potential energy. The... |
| Tipo: Text |
Palavras-chave: Baroclinic flows; Instability; Waves in rotating fluids. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00211/32230/30753.pdf |
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