This article examines the dynamical coupling between the stratosphere and troposphere by considering the effect of direct perturbations to stratospheric potential vorticity on the evolution of midlatitude baroclinic instability in a simple extension of an Eady model. A simulation in which stratospheric potential vorticity is exactly zero is used as a control case, and both zonally symmetric and...

The two main principles underlying the use of isentropic maps of potential vorticity to represent dynamical processes in the atmosphere are reviewed, including the extension of those principles to take the lower boundary condition into account. The first is the familiar Lagrangian conservation principle, for potential vorticity (PV) and potential temperature, which holds approximately when adve...

Monthly mean NCEP reanalysis potential vorticity fields at the 650 K isentropic level over the Northern and Southern Hemispheres between 1979 and 1997 were studied using multivariate analysis tools. Principal component analysis in the T-mode was applied to demonstrate the validity of such statistical techniques for the study of stratospheric dynamics and climatology. The method, complementarily...

The use of eddy flux of thickness between density surfaces has become a familiar starting point in oceanographic studies of adiabatic eddy effects on the mean density distribution. In this study, a dynamical analogy with the density thickness flux approach is explored to reexamine the theory of nonzonal wave–mean flow interaction in two-dimensional horizontal flows. By analogy with the density ...

Introduction: Potential vorticity (hereafter PV) is a dynamical tracer which is a product of the absolute vorticity and static stability of the atmosphere. PV can be redistributed but neither created or destroyed on an isentropic surface in the absence of friction and diabatic processes [1]. The conservation principle explains why PV is used to study polar vortices on Earth. PV contains informa...

Introduction: Potential vorticity (hereafter PV) is a dynamical tracer which is a product of the absolute vorticity and static stability of the atmosphere. PV can be redistributed but neither created or destroyed on an isentropic surface in the absence of friction and diabatic processes [1]. The conservation principle explains why PV is used to study polar vortices on Earth. PV contains informa...

Nambu proposed a generalization of Hamiltonian dynamics in the form dF/dt = {F,H,Z}, which conserves H and Z because the Nambu bracket {F,H,Z} is completely antisymmetric. The equations of fluid dynamics fit Nambu’s form with H the energy and Z a quantity related to potential vorticity. This formulation makes it easy, in principle, to construct numerical fluidmodels that conserve analogues of H...

3 Anatoly Abrashkin and Efim Pelinovsky 4 5 a National Research University Higher School of Economics (HSE), Nizhny Novgorod 6 603155, Russia 7 b Institute of Applied Physics, 603950, 46 Ulyanov str., Nizhny Novgorod, Russia 8 c Nizhny Novgorod State Technical University, Nizhny Novgorod, Russia 9 10 11 Abstract: 12 The nonlinear Schrödinger equation (NLS equation) describing weakly 13 rotation...

We discuss here the evolution of vorticity and potential vorticity (PV) for a bottom current crossing a marine channel in shallow-water approximation, focusing on the effect of friction and mixing. The purpose of this research is indeed to investigate the role of friction and vertical entrainment on vorticity and PV spatial evolution in channels or straits when along-channel morphology variatio...

A theory for the transport of a tracer in flow dominated by turbulence and jets is developed and tested. Such a system can be taken as a model either for the stirring of true tracers in the atmosphere and ocean, or, less obviously, for the stirring of baroclinic potential vorticity by non-zonal flow in the ocean. The flow is generated by two-dimensional turbulence with a mean vorticity gradient...