scholarly journals Observation and simulation of wave breaking in the southern hemispheric stratosphere during VORCORE

2013 ◽  
Vol 31 (4) ◽  
pp. 675-687
Author(s):  
M. Moustaoui ◽  
H. Teitelbaum ◽  
A. Mahalov
Keyword(s):  
Wave Breaking ◽  
Rossby Waves ◽  
Surf Zone ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Stationary Wave ◽  
Linear Wave ◽  
Rossby Wave Breaking ◽  
Wind Speeds ◽  
Antarctic Polar Vortex

Abstract. An interesting occurrence of a Rossby wave breaking event observed during the VORCORE experiment is presented and explained. Twenty-seven balloons were launched inside the Antarctic polar vortex. Almost all of these balloons evolved in the stratosphere around 500K within the vortex, except the one launched on 28 October 2005. In this case, the balloon was caught within a tongue of high potential vorticity (PV), and was ejected from the polar vortex. The evolution of this event is studied for the period between 19 and 25 November 2005. It is found that at the beginning of this period, the polar vortex experienced distortions due to the presence of Rossby waves. Then, these waves break and a tongue of high PV develops. On 25 November, the tongue became separated from the vortex and the balloon was ejected into the surf zone. Lagrangian simulations demonstrate that the air masses surrounding the balloon after its ejection were originating from the vortex edge. The wave breaking and the development of the tongue are confined within a region where a planetary Quasi-Stationary Wave 1 (QSW1) induces wind speeds with weaker values. The QSW1 causes asymmetry in the wind speed and the horizontal PV gradient along the edge of the polar vortex, resulting in a localized jet. Rossby waves with smaller scales propagating on top of this jet amplify as they enter the jet exit region and then break. The role of the QSW1 on the formation of the weak flow conditions that caused the non-linear wave breaking observed near the vortex edge is confirmed by three-dimensional numerical simulations using forcing with and without the contribution of the QSW1.

scholarly journals Energetic particle induced intra-seasonal variability of ozone inside the Antarctic polar vortex observed in satellite data

2015 ◽  
Vol 15 (6) ◽  
pp. 3327-3338 ◽  
Author(s):  
T. Fytterer ◽  
M. G. Mlynczak ◽  
H. Nieder ◽  
K. Pérot ◽  
M. Sinnhuber ◽  
...  
Keyword(s):  
Geomagnetic Activity ◽  
Seasonal Variability ◽  
Transport Model ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Quiet Time ◽  
Significance Level ◽  
Antarctic Polar Vortex ◽  
Ap Index ◽  
The Antarctic

Abstract. Measurements from 2002 to 2011 by three independent satellite instruments, namely MIPAS, SABER, and SMR on board the ENVISAT, TIMED, and Odin satellites are used to investigate the intra-seasonal variability of stratospheric and mesospheric O3 volume mixing ratio (vmr) inside the Antarctic polar vortex due to solar and geomagnetic activity. In this study, we individually analysed the relative O3 vmr variations between maximum and minimum conditions of a number of solar and geomagnetic indices (F10.7 cm solar radio flux, Ap index, ≥ 2 MeV electron flux). The indices are 26-day averages centred at 1 April, 1 May, and 1 June while O3 is based on 26-day running means from 1 April to 1 November at altitudes from 20 to 70 km. During solar quiet time from 2005 to 2010, the composite of all three instruments reveals an apparent negative O3 signal associated to the geomagnetic activity (Ap index) around 1 April, on average reaching amplitudes between −5 and −10% of the respective O3 background. The O3 response exceeds the significance level of 95% and propagates downwards throughout the polar winter from the stratopause down to ~ 25 km. These observed results are in good qualitative agreement with the O3 vmr pattern simulated with a three-dimensional chemistry-transport model, which includes particle impact ionisation.

scholarly journals Quantifying Asymmetric Wave Breaking and Two-Way Transport

2004 ◽  
Vol 61 (22) ◽  
pp. 2735-2748 ◽  
Author(s):  
Noboru Nakamura
Keyword(s):  
Wave Breaking ◽  
Polar Vortex ◽  
Effective Diffusivity ◽  
The Other ◽  
Stratospheric Polar Vortex ◽  
Air Masses ◽  
Rossby Wave Breaking ◽  
Advection Diffusion Equation ◽  
Extratropical Tropopause ◽  
Asymmetric Wave

Abstract Effective diffusivity calculated from a scalar field that obeys the advection–diffusion equation has proved useful for estimating the permeability of unsteady boundaries of air masses such as the edge of the stratospheric polar vortex and the extratropical tropopause. However, the method does not discriminate the direction of transport—whereas some material crosses the boundary from one side to the other, some material does so in the other direction—yet the extant method concerns only the net transport. In this paper, the diagnostic is extended to allow partitioning of fluxes of mass and tracer into opposing directions. This is accomplished by discriminating the regions of “inward” and “outward” wave breaking with the local curvature of the tracer field. The utility of the new method is demonstrated for nonlinear Kelvin– Helmholtz instability and Rossby wave breaking in the stratosphere using a numerically generated tracer. The method successfully quantifies two-way transport and hence the direction of wave breaking—the predominantly equatorward breaking of Rossby waves in the extratropical middle stratosphere, for example. Isolated episodes of mixing are identified well, particularly by the mass flux that primarily arises from the tracer filaments. Comparison of different transport schemes suggests that the results are reasonably robust under a varying subgrid representation of the model.

scholarly journals Vortex Layer on the β-Plane in the Miles – Ribner Formulation. Pole on the Real Axis

2021 ◽  
Vol 28 (5) ◽  
Author(s):  
V. G. Gnevyshev ◽  
T. V. Belonenko ◽  
◽  
Keyword(s):  
Rossby Waves ◽  
Zonal Flow ◽  
Stationary Wave ◽  
Linear Wave ◽  
Background Flow ◽  
Pure Radiation ◽  
New Class ◽  
Vortex Layer ◽  
Wave Disturbances ◽  
Definition Of

Purpose. The problem of a non-zonal vortex layer on the β-plane in the Miles – Ribner formulation is considered. It is known that in the absence of the β-effect, the vortex layer has no neutral eigenmodes, and the available two ones (varicose and sinusoidal) are unstable. Initially, generalization of the problem to the β-plane concerned only the zonal case. The problem for a non-zonal vortex layer is examined for the first time in the paper. It is known that in the WKB approximation for the linear wave disturbances (regardless of whether a zonal or non-zonal background flow is considered), there is an adiabatic invariant in the form of the law of the enstrophy (vorticity) conservation. For the zonal vortex layer, the enstrophy conservation law also holds, and no vorticity exchange occurs between the waves and the flow in the zonal case. The non-zonal vortex layer has qualitatively different features; particularly, it does not retain enstrophy. Thus, as a result, there appears a new class of solutions which can be interpreted as pure radiation of the Rossby waves by a non-zonal flow. Generalizing the vortex layer problem on the β-plane to the non-zonal case constitutes the basic aim of the present study. Methods and Results. A new class of linear stationary wave solutions, namely the Rossby waves, is found. It is shown a non-zonal flow can be directed in one way, whereas the stationary wave disturbances can move in the opposite (contrary) direction. The coexistence of such solutions for the shear non-zonal flow and stationary wave disturbances takes place due to the influence of the external force and mathematically comes from a non-self-adjoining character of the linear operator for a non-zonal background flow. Conclusions. There exists a new class of solutions that can be interpreted as pure radiation of the Rossby waves by a non-zonal flow. There is no such solution for a zonal flow. It is just non-zoning that gives the effect of pure radiation and corresponds to the classical definition of radiation. This approach makes it possible to eliminate inconsistency in terminology, when instabilities are mistakenly called radiation, and radiation – pure radiation.

scholarly journals A New Three Dimensional Dissipative Boussinesq Equation for Rossby Waves and Its Multiple Soliton Solutions☆

2021 ◽  
Author(s):  
Liguo Chen ◽  
Liangui Yang
Keyword(s):  
Rossby Waves ◽  
Boussinesq Equation ◽  
Three Dimensional ◽  
Soliton Solutions ◽  
Boussinesq Equations ◽  
Auxiliary Equation ◽  
Linear Wave ◽  
Auxiliary Equation Method ◽  
Multiple Soliton Solutions ◽  
New Equation

Abstract A new three dimensional nonlinear dynamic theoretical model is derived from fluid mechanics system. In this paper, From the quasi-geostrophic barotropic potential vorticity equation, we obtain a three dimensional dissipative Boussinesq equation by the reduced perturbation method, i.e.utt +e1uxx +e2(u2)xx + e3utxy + e4uxxxx + e5uxxyy = 0. It is emphasized that the new equation is different from the existing Boussinesq equations, which describe the three dimensional nonlinear Rossby waves in the atmosphere. Moreover, we explore the dispersion relation of the linear wave through the new equation. Using the trial function and auxiliary equation method, the two kinds of soliton solutions of the equation are obtained successfully. Finally, the formation mechanism of Rossby waves is discussed by multiple soliton solutions.

Gravity wave focusing on the Antarctic polar vortex using Gaussian-beam approximation in horizontally non-uniform flows

2021 ◽  
Author(s):  
Claudio Rodas ◽  
Manuel Pulido
Keyword(s):  
Gaussian Beam ◽  
Wave Field ◽  
Gravity Wave ◽  
Polar Vortex ◽  
Linear Wave ◽  
Beam Approximation ◽  
Nonuniform Flows ◽  
Antarctic Polar Vortex ◽  
Ray Path ◽  
The Antarctic

AbstractRay path theory is an asymptotic approximation to the wave equations. It represents efficiently gravity wave propagation in non-uniform background flows so that it is useful to develop schemes of gravity wave effects in general circulation models. One of the main limitations of ray path theory to be applied in realistic flows is in caustics where rays intersect and the ray solution has a singularity. Gaussian beam approximation is a higher-order asymptotic ray path approximation which considers neighboring rays to the central one and thus it is free of the singularities produced by caustics. A previous implementation of the Gaussian beam approximation assumes a horizontally uniform flow. In this work, we extend the Gaussian beam approximation to include horizontally nonuniform flows. Under these conditions the wave packet can undergo horizontal wave refraction producing changes in the horizontal wavenumber, which affects the ray path as well as the ray tube cross-sectional area and so the wave amplitude via wave action conservation. As an evaluation of the Gaussian beam approximation in horizontally nonuniform flows a series of proof-of-concept experiments is conducted comparing the approximation with the linear wave solution given by the WRF model. A very good agreement in the wave field is found. An evaluation is conducted with conditions that mimic the Antarctic polar vortex and the orography of the Southern flank of South America. The Gaussian beam approximation nicely reproduces the expected asymmetry of the wave field. A much stronger disturbance propagates towards higher latitudes (polar vortex) compared to lower latitudes.

scholarly journals Transport out of the Antarctic polar vortex from a three-dimensional transport model

2002 ◽  
Vol 107 (D11) ◽  
pp. ACL 8-1-ACL 8-8 ◽  
Author(s):  
Shuhua Li ◽  
Eugene C. Cordero ◽  
David J. Karoly
Keyword(s):  
Transport Model ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Antarctic Polar Vortex ◽  
The Antarctic

scholarly journals On the role of Rossby wave breaking in the quasi‐biennial modulation of the stratospheric polar vortex during boreal winter

2020 ◽  
Vol 146 (729) ◽  
pp. 1939-1959
Author(s):  
Hua Lu ◽  
Matthew H. Hitchman ◽  
Lesley J. Gray ◽  
James A. Anstey ◽  
Scott M. Osprey
Keyword(s):  
Rossby Wave ◽  
Wave Breaking ◽  
Polar Vortex ◽  
Boreal Winter ◽  
Stratospheric Polar Vortex ◽  
Rossby Wave Breaking

scholarly journals Insights into the three-dimensional Lagrangian geometry of the Antarctic polar vortex

2017 ◽  
Vol 24 (3) ◽  
pp. 379-392 ◽  
Author(s):  
Jezabel Curbelo ◽  
Víctor José García-Garrido ◽  
Carlos Roberto Mechoso ◽  
Ana Maria Mancho ◽  
Stephen Wiggins ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Strong Mixing ◽  
Mixing Processes ◽  
Stratospheric Polar Vortex ◽  
Vertical Extension ◽  
Antarctic Polar Vortex ◽  
The Antarctic ◽  
Lagrangian Geometry

Abstract. In this paper we study the three-dimensional (3-D) Lagrangian structures in the stratospheric polar vortex (SPV) above Antarctica. We analyse and visualize these structures using Lagrangian descriptor function M. The procedure for calculation with reanalysis data is explained. Benchmarks are computed and analysed that allow us to compare 2-D and 3-D aspects of Lagrangian transport. Dynamical systems concepts appropriate to 3-D, such as normally hyperbolic invariant curves, are discussed and applied. In order to illustrate our approach we select an interval of time in which the SPV is relatively undisturbed (August 1979) and an interval of rapid SPV changes (October 1979). Our results provide new insights into the Lagrangian structure of the vertical extension of the stratospheric polar vortex and its evolution. Our results also show complex Lagrangian patterns indicative of strong mixing processes in the upper troposphere and lower stratosphere. Finally, during the transition to summer in the late spring, we illustrate the vertical structure of two counterrotating vortices, one the polar and the other an emerging one, and the invariant separatrix that divides them.

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