摘要:

We discuss the problem, of the energy balance of a planetary atmosphere: whether the atmospheric structure is under radiative control or whether it is significantly influenced by large scale fluid motions.

ISSN:0016-7991    

DOI:10.1080/03091927009365766

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

It is shown that, even for vanishingly small diffusivities of momentum and heat, a rotating stratified zonal shear flow is more unstable to zonally symmetric disturbances than would be indicated by the classical inviscid adiabatic criterion, unless σ, the Prandtl number, = 1. Both monotonic instability, and growing oscillations ("overstability") are involved, the former determining the stability criterion and having the higher growth rates. The more σ differs from 1, the larger the region in parameter space for which the flow is stable by the classical criterion, but actually unstable.

ISSN:0016-7991    

DOI:10.1080/03091927009365767

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

The “viscous overturning” mechanism, described in its simplest form by the linearized instability theory of the previous paper, is discussed in relation to certain numerical solutions recently obtained by G. P. Williams for steady thermally driven axisymmetric convective flow of water (Prandtl number = 7) in a rotating annulus differentially heated in the horizontal, in the “upper symmetric regime” parameter range. Viscous overturning plays an important and clearly identifiable role in the flows A3B, A4 and A5, which have free‐slip side walls and top surface, and a less clearcut role in A3 and B2, for which only the top surface is free. The discussion leads to various predictions about annulus flows not yet studied in detail.

ISSN:0016-7991    

DOI:10.1080/03091927009365768

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

A study is made to determine the stability properties of a baroclinic zonal current on which small amplitude three‐dimensional non‐geostrophic disturbances are superimposed. The flow is assumed to be bounded to the north and south by rigid vertical walls and the Rossby numberRois taken to be small compared to unity. It is then shown that if the perturbation quantities are expanded in power series inRothe leading or zero order terms in the series correspond to the quasi‐geostrophic solution obtained by Eady (1949) and that the higher order terms represent the “non‐geostrophic” effects neglected by the latter.

ISSN:0016-7991    

DOI:10.1080/03091927009365769

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Two models of floating heat sources are studied. In the first model the motion of two line heat sources constrained to float at an arbitrary depth in a viscous fluid is determined in the limit of small convection velocities. It is found that the sources drift apart and at great separation attain a constant velocity proportional to the square root of the heat flux. The second model is a floating block heat source, presumed to be very long compared to its depth. It is found to exhibit periodic excursions between the end walls of the fluid container with the same dependence of velocity on heat flux as the line sources. A series of experiments are described which exhibit various features of the theory. The numerical values found when the theory is applied to the earth suggest that the idealized flows may be useful in the interpretation of continental drift.

ISSN:0016-7991    

DOI:10.1080/03091927009365770

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

If a vertically oriented hypodermic syringe with the plunger removed is filled with salt water and partially submerged in a beaker of fresh water, then under the proper conditions, the system develops finite amplitude oscillations. These oscillations appear as a downward jet of salt water, followed by an upward jet of fresh water, and so on for many cycles. The geometry of the syringe determines the period of the oscillations: a long, small diameter needle yields a slow, viscous flow; a short, large diameter needle yields fast inviscid pumping. Theoretically, a time‐dependent Hagen‐Poiseuille pipe flow model describes the oscillations; furthermore, the oscillations can be divided into two modes, depending on whether viscous or non‐linear damping predominates. When viscous damping predominates, the geometry of the syringe determines the period of the oscillations, which are independent of the density difference ?ρ except as the viscosity varies with density. When non‐linear damping predominates, the period is proportional to (?ρ)1/2. Experiments confirm the existence of both modes.

ISSN:0016-7991    

DOI:10.1080/03091927009365771

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Tidal pressures and currents were measured with self‐contained capsules dropped to the sea floor for one month at distances of 175, 190, and 500 nautical miles from San Diego. These observations, together with a one‐week bottom pressure record by Filloux at 750 n miles, and three half‐week bottom current records by Isaacset al,at intermediary distances, were analyzed for tidal components by cross‐correlation with a noise‐free reference time series. (For short records this method has some merit over classical tide analysis.) It was found that the tide decays seaward to e‐1times the coastal amplitude over a distance of order 1000 km for the semidiurnal species, slower for the diurnal species. Tidal currents turn counterclockwise, and are polarized with maximum flow parrallel to shore in the direction of tidal propagation (320°T) at local high tide. The current amplitude is roughly 2 cm/sec for the semidiurnal component, 1 cm/sec for the diurnal component. Superimposed baroclinic tidal currents lead to poor signal: noise ratios (between 1:1 and 10:1) for the barotropic currents. In contrast, the ratio is typically 1000:1 for the bottom pressures and generally exceeds that for coastal tide stations of comparable duration. Published I.H.B. tidal constants for exposed Californiacoastalstations indicate “upshore” (towards 320°T) propagation at 140 m/sec for semidiurnal tides. 214 m/sec for diurnal tides.

ISSN:0016-7991    

DOI:10.1080/03091927009365772

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

Second order effects due to the presence of a first order free oscillation at a single frequency in a variable depth rotating ocean are examined. It is found that the second order Lagrangian mean velocity (mass transport velocity) satisfies the linearized equations for unforced steady geostrophic motion. This implies that if the ocean basin is laterally bounded and contains no closed geostrophic contours, the second order Lagrangian mean velocity vanishes everywhere.

ISSN:0016-7991    

DOI:10.1080/03091927009365773

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

摘要:

This paper describes the linear response of an inviscid two‐layer model of a deep ocean on anf‐plane to a hurricane translating across the surface at constant speed. The forcing is a localized, radially‐symmetric pattern of positive wind stress curl and negative pressure anomaly. Only the steady state response is considered. The principal result is the identification of an internal wake in the lee of the storm, present when the translation speed of the storm exceeds the baroclinic long wave speed. The amplitude of the wake depends on the length of time over which the stress is experienced at a given point. The angle of the wedge filled by the wake is small, an effect due to the fact that the scale of a hurricane is typically larger than the baroclinic radius of deformation. After the wake disperses, a geostrophically balanced baroclinic ridge remains along the storm track.

ISSN:0016-7991    

DOI:10.1080/03091927009365774

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor

ISSN:0016-7991    

DOI:10.1080/03091927009365765

出版商:Taylor & Francis Group    

年代:1970

数据来源: Taylor