TY - JOUR

T1 - Rossby Waves on Non-zonal Flows

T2 - Vertical Focusing and Effect of the Current Stratification

AU - Gnevyshev, Vladimir G.

AU - Badulin, Sergei I.

AU - Koldunov, Aleksey V.

AU - Belonenko, Tatyana V.

N1 - Publisher Copyright: © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/8

Y1 - 2021/8

N2 - This paper considers the interaction of Rossby waves with large-scale flows. We focus on the case of a non-zonal baroclinic plane-parallel flow with vertical shear. We develop short-wave asymptotics for linear waves in the vicinity of the critical layer. Vertical wave modes (eigenfunctions) of the corresponding boundary problem are presented in terms of Hermite polynomials. In addition to the classical case, when the wave modes are focused on the absolute minimum of the vertical profile of the baroclinic flow velocity, we show that there is another option when a mode is formed with focusing not on the minimum, but the absolute maximum of the vertical profile of the background flow velocity. The new option makes it possible to implement new dynamical regimes that are considered in the paper. We obtain a new criterion that limits the number of vertical modes and, thus, determines regimes of the mode localization in depth or its de-localization. Theoretical criteria of different regimes of Rossby wave dynamics in the non-zonal baroclinic are presented in terms of two dimensionless variables: B associated with "an effective β -parameter" and S= N2/ f2 (N is the Brunt–Väisälä frequency, and f is the Coriolis parameter). The analysis of experimental data shows the relevance of theoretically predicted effects.

AB - This paper considers the interaction of Rossby waves with large-scale flows. We focus on the case of a non-zonal baroclinic plane-parallel flow with vertical shear. We develop short-wave asymptotics for linear waves in the vicinity of the critical layer. Vertical wave modes (eigenfunctions) of the corresponding boundary problem are presented in terms of Hermite polynomials. In addition to the classical case, when the wave modes are focused on the absolute minimum of the vertical profile of the baroclinic flow velocity, we show that there is another option when a mode is formed with focusing not on the minimum, but the absolute maximum of the vertical profile of the background flow velocity. The new option makes it possible to implement new dynamical regimes that are considered in the paper. We obtain a new criterion that limits the number of vertical modes and, thus, determines regimes of the mode localization in depth or its de-localization. Theoretical criteria of different regimes of Rossby wave dynamics in the non-zonal baroclinic are presented in terms of two dimensionless variables: B associated with "an effective β -parameter" and S= N2/ f2 (N is the Brunt–Väisälä frequency, and f is the Coriolis parameter). The analysis of experimental data shows the relevance of theoretically predicted effects.

KW - adhering

KW - barotropic and baroclinic modes

KW - critical layer

KW - overshooting phenomenon

KW - Rossby waves

KW - WKBJ approximation (geometric optics)

KW - zonal and non-zonal baroclinic flows

KW - HORIZONTAL INHOMOGENEITIES

KW - BAROCLINIC INSTABILITY PARAMETERS

KW - BOTTOM TOPOGRAPHY

KW - PYCNOCLINE

KW - MEAN FLOW

KW - INTERNAL WAVES

KW - DYNAMICS

KW - SURFACE

KW - PROPAGATION

UR - http://www.scopus.com/inward/record.url?scp=85108975401&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/bad1f85a-01d1-34a4-b7de-35e0afb35d4d/

U2 - 10.1007/s00024-021-02799-8

DO - 10.1007/s00024-021-02799-8

M3 - Article

AN - SCOPUS:85108975401

VL - 178

SP - 3247

EP - 3261

JO - Pure and Applied Geophysics

JF - Pure and Applied Geophysics

SN - 0033-4553

IS - 8

ER -