The formation of orographic wakes and vortices is studied within the context of numerically simulated viscous flow with uniform basic-state wind and stability past elongated free-slip ridges. The viscosity and thermal diffusivity are sufficiently large that the onset of small-scale turbulence is suppressed. It is found in Part I of this study that wake formation in the viscous flow is closely t...

In this study, the relation between the interior and the surface dynamics for nonlinear baroclinically unstable flows is examined using the concepts of potential vorticity. First, it is demonstrated that baroclinic unstable flows present the property that the potential vorticity mesoscale and submesoscale anomalies in the ocean interior are strongly correlated to the surface density anomalies. ...

A Poisson regression between the observed climatology of tropical cyclogenesis (TCG) and largescale climate variables is used to construct a TCG index. The regression methodology is objective and provides a framework for the selection of the climate variables in the index. Broadly following earlier work, four climate variables appear in the index: low-level absolute vorticity, relative humidity...

[1] We present an experimental and numerical study of a rotating fluid with a zonal flow produced from small-scale eddies, a common feature of many planetary systems. The apparatus consists of a water-filled annular tank with a sloped bottom. Flow is forced mechanically at small, nonaxisymmetric scales. Potential vorticity is materially conserved and well-mixed. This implies the existence of no...

We conduct long simulations with a Hamiltonian particle-mesh method for ideal fluid flow, to determine the statistical mean vorticity field. Lagrangian and Eulerian statistical models are proposed for the discrete dynamics, and these are compared against numerical experiments. The observed results are in excellent agreement with theoretical models, as well as the continuum statistical mechanica...

A new approach to consider balance dynamics for modelling slow vortical motion is suggested within the rotating shallow water primitive equations. Instead of a traditional approach using divergence and ageostrophic vorticity as fast variables, the velocity is exactly expressed as a sum of the gradient part, described by a Bernoulli function, and the rest, an agradient part, proportional to the ...