摘要:

The classical barotropic ocean model of Veronis (1966) is re-examined to verify the possible existence of Fofonoff's (1954) steady free inertial mode with linear functional relationship between the potential vorticity and the steamfunction with inertial boundary layers along the ocean basin. It is found that Fofonoffs particular solution cannot be realized physically since the flow develops barotropic instability. When nearly inviscid steady state solutions are possible, the functional relation between the potential vorticity and the streamfunction is determined by the wind stress distribution and viscous dissipation.

ISSN:0309-1929    

DOI:10.1080/03091928508208784

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

The theory of baroclinic instability is extended to include strong horizontal shears. The f-plane and anelastic approximations are used, but the assumption that the Rossby number is small is relaxed. Although this problem is nongeostrophic, much of the standard theory, including necessary conditions for instability and a semicircle theorem, generalize readily for disturbances of low zonal wavenumber.

ISSN:0309-1929    

DOI:10.1080/03091928508208785

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We consider vertical magneto-acoustic-gravity waves in an atmosphere under a constant magnetic field, and show that (Figure 1), in addition to the Alfvén wave, there exists a hydromagnetic-gravity wave, which is of fourth-order in the general case of an oblique magnetic field, and reduces to a second-order acoustic/magnetosonicgravity wave respectively for a vertical/horizontal magnetic field. A method is developed to solve exactly linear wave equations with certain types of variable (e.g., exponential) coefficients, describing waves of any order and arbitrary frequency in strongly stratified media. The method relies on the transformation of the wave equation into a standard type [equation (11a)], which on inspection is seen to have general properties such as: (i) cut-off frequencies and related wave components (Figure 2, Table I); (ii) the asymptotic amplitude and phase laws holding at high-altitudes (Table II); (iii) the existence and location of critical levels (Figure 3, Table III). The method also yields exact, explicit solutions, in the form of rapidly converging series, for high-order functions of the first, second and third kinds, which can be interpreted as generalizations of the second-order Bessel, Neumann and Hankel functions. These functions specify the four particular integrals of the general hydromagnetic gravity wave equation, a pair for each of the dynamic and magnetic components (Table V), which are coupled beyond the leading order. Simplified formulae are obtained in the initial and asymptotic regimes, at low- and high-altitude respectively, demonstrating (Table IV): (a) the evolution of all wave variables, viz. horizontal and vertical displacements, mass density and magnetic field perturbations, and gas and magnetic pressures; (b) the equipartition or biasing of the kinetic, compressional, potential and magnetic energy densities. The exact solutions specify the eigen-frequencies and waveforms of standing modes (Figure 4), and the amplitude and phases of propagating waves (Figures 5, 6, 7), demonstrating the dependence upon wave frequency, plasma β and magnetic field inclination.

ISSN:0309-1929    

DOI:10.1080/03091928508208786

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Recent calculations suggest that the bulk of the solar magnetic field may be stored in a thin convectively stable region situated between the convection zone proper and the radiative zone. Determining the stability properties of such a field is therefore important with implications for both the generation and escape of magnetic flux. The magneto-Boussinesq equations are used to perform a linear stability analysis of a static plane layer. Several new instability mechanisms are revealed showing previous ideas concerning magnetic buoyancy instabilities to be over simplified. The most important result is that instability may occur even for fields whichincreasewith height. Detailed results are presented for 2 and 3 dimensional motions for a weakly stratified magnetic field together with a simple calculation for the 2 dimensional instability of a strongly varying field.

ISSN:0309-1929    

DOI:10.1080/03091928508208787

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

We apply the MHD energy principle to the stability of a magnetized atmosphere which is bounded below by much denser fluid, as is the solar corona. We treat the two fluids as ideal; the approximation which is consistent with the energy principle, and use the dynamical conditions that must hold at a fluid-fluid interface to show that if vertical displacements of the lower boundary are permitted, then the lower atmosphere must be perturbed as well. However, displacements which do not perturb the coronal boundary can be properly treated as isolated perturbations of the corona alone.

ISSN:0309-1929    

DOI:10.1080/03091928508208788

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Edited by D. M. Burridge and E. Kallen. Springer-Verlag, 1984, xii+274 pp. Price: U.S. $17.50. ISBN 3 540 12827 1.

ISSN:0309-1929    

DOI:10.1080/03091928508208789

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

By Ronald T. Merrill and Michael W. McElhinny. Academic Press, 420 pp. Paperback: $30.00/£17.50 (UK only) ISBN: 0 12 491242 7 Hardback $67.50/$39.50 (UK only) ISBN: 0 12 491240 0 1983.

ISSN:0309-1929    

DOI:10.1080/03091928508208790

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

By W. Menke. Academic Press, 1984, 280 pages. Price: U.S. $42.50. ISBN 0 124 90920 5.

ISSN:0309-1929    

DOI:10.1080/03091928508208791

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Edited by A. A. Galeev and R. N. Sudan. North-Holland Publishing Company, 1984, about 850 pages. Price: Dfl. 420.00 (U.S. $190.50). ISBN 0 444 86645 0.

ISSN:0309-1929    

DOI:10.1080/03091928508208792

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Edited by A. Nishida. D. Reidel Publishing Company, xii+348 pp. Cloth Dfl. 130,-/US $49.50 (ISBN 0 8130 0601 5) 1982.

ISSN:0309-1929    

DOI:10.1080/03091928508208793

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor