摘要:

A high vertical resolution model is used to examine the instability of a baroclinic zonal flow and a finite amplitude topographically forced wave. Two families of unstable modes are found, consisting of zonally propagating most unstable modes, and stationary unstable modes. The former have time scale and spatial structure similar to baroclinic synoptic disturbances, but are localized in space due to interaction with the zonally asymmetric forcing. These modes transport heat efficiently in both the zonal and meridional directions. The second family of stationary unstable modes has characteristics of modes of low frequency variability of the atmosphere. They have time scales of 10 days and longer, and are of planetary scale with an equivalent barotropic vertical structure. The horizontal structure resembles blocking flows. They are maintained by available potential energy of the basic wave, and have large zonal heat fluxes. The results for both families of modes are interpreted in terms of an interaction between forcing and baroclinic instability to create favoured regions for eddy development. Applications to baroclinic planetary waves are also considered.

ISSN:0309-1929    

DOI:10.1080/03091928708208813

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The linear instability of a weakly non-zonal barotropic flow is investigated numerically using the spectral method and analytically via WKB theory. The basic steady-state is the consequence of the interaction of a constant mean zonal wind and a sinusoidal topography. The (numerically determined) slowest growing eigenmode is stationary, on the scale of the topography and depends crucially on a form drag mechanism. The fastest growing eigenmode, on the other hand, does not involve a form drag mechanism but depends rather on the presence of local shears inherent in the basic flow itself. A large part of the discussion involves an analysis of the structure and energetics of the fastest growing eigenmode.

ISSN:0309-1929    

DOI:10.1080/03091928708208814

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The problem of unsteady long waves generated by any horizontal and symmetrically distributed, time-periodic surface wind on a rotating ocean is analysed for large times and distances. Uniform asymptotic estimates of the surface displacement in the unsteady state are obtained. The steady-state wave and velocity fields at any distance are also determined. Some characteristics of the unsteady and steady motions are described. Also noted are the features that distinguish the motion from its one-dimensional analogue for which a non-uniform analysis in the unsteady state along with a large-distance form of the surface elevation are already known.

ISSN:0309-1929    

DOI:10.1080/03091928708208815

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Small amplitude oscillations of a uniformly rotating, density stratified, Boussinesq, electrically conducting, non-dissipative fluid are examined in the geometry of a spherical shell. The basic magnetic field is assumed to be toroidal and is allowed to be an arbitrary axisymmetrical function of space. The basic density distribution is allowed to be an arbitrary function of space, consistent with the gravitational potential and the toroidal magnetic field. Conserved energy integrals are constructed and these constraints are used to determine sufficient conditions for stability. The stable waves are, in general, spatially trapped. Explicit expressions are obtained for the “turning surfaces” that delineate the regions in which waves are trapped. These expressions are used to illustrate trapped hydromagnetic waves in the Earth's fluid core.

ISSN:0309-1929    

DOI:10.1080/03091928708208816

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Edited by F. D. Kahn, VNU Science Press, Utrecht, 1985. viii + 329 pp. $58 (ISBN 90 6764053 0).

ISSN:0309-1929    

DOI:10.1080/03091928708208817

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Edited by T. C. Lin. Science Press, Beijing and VNU Science Press, Utrecht, 1984. xvi+ 1154pp. $143 (ISBN 90 6764 005 0).

ISSN:0309-1929    

DOI:10.1080/03091928708208818

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

By Paul Melchior. Pergamon Press, 1986. vi + 256 pp. $19.95 (ISBN 0080326064).

ISSN:0309-1929    

DOI:10.1080/03091928708208819

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor