bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the motion of a cyclone embedded in a uniform flow
Authors: Adem Julián , Lezama Pedro 
Published: January 2012

Using the barotropic model, an analytical expression for the motion of a cyclone embedded in a uniform flow is obtained. The solution contains as parameters the radius of the vortex, the maximum velocity in the vortex, the velocity of the uniform flow and the variation of the Coriolis parameter.
It is shown that, if the variation of the Coriolis parameter is neglected, a cyclone initially embedded in a uniform flow moves with the velocity of the flow. However, superimposed with that motion there always exists a north-westward translation due to the variation of the Coriolis parameter that in some cases represents a non-negligible percentage of the total displacement of a hurricane.
A Calculation of the Effect of Large-Scale Heat Sources on Southern Hemisphere Sub-Tropical Wind Flow
Authors: De Lisle J. F. , Harper J. F. 
Published: January 2012

The quasi-stationary effects of large-scale heat sources on a baroclinic model atmosphere in which low-level zonal easterly winds decreasing with height are surmounted by Zonal westerly winds increasing with height are calculated. Two cases are considered : (1) where the surface of zero zonal wind is parallel to the bottom boundary, (2) where it slopes upwards from this boundary towards the north.
The latter case incorporates roughly the more important features of the mean summer sub-tropical flow in the Australian region.
The results found by calculation were compared with the effects produced in the general circulation in summer by the Australian continent and similarities were found.
Trapping of Low Frequency Oscillations in an Equatorial “Boundary Layer”
Authors: Stern Melvin E. 
Published: January 2012

A thin layer of water (thickness h) and its spherical boundaries (mean radius R) rotate with uniform angular velocity Ω. Using an asymptotic expansion in the parameter h/R ⪡ 1 we investigate the inertial oscillations of “large scale” disturbances at the equator. It is found that the vertical constraints on the motion inhibit the lateral (poleward) propagation of low frequency energy. Solutions of the non-separable eigenvalue problem give standing oscillations whose longest period is (R/h)½ (2π/Ω) and which are self-confined within a distance of order (Rh)½ on either side of the equator. This axial symmetric calculation is probably valid for disturbances whose eaet-west wave-length is large compared with the width of the “boundary layer” (Rh)½. t is suggested that a trapped wave can transfer energy to a mean flow at the equator, as the result of the correlation between the velocity components of the eigenfunction.
In the bottom water of the equatorial ocean, where, the stratification is small, there might be oscillations whose period is of the order of a month and which extended some 300 km north and south of the equator. When the static stability is appreciable the effect can only be expected if, on thie time scale, the fluid dissipates temperature perturbations much more rapidly than momentum.
A preliminary Investigation of the Daily Meridional Transfer of Atmospheric Water Vapour between the Equator and 40°N
Authors: Van de Boogaard Henry M. E. 
Published: January 2012

As a preliminary investigation into the daily variation of the meridional flux of atmospheric water vapour between the equator and 40°N, the transport has been computed from the analysed fields of specific humidity (q) and the v-component of the wind field. The analysis is based on the observations taken at a single synoptic time. The computations confirm earlier results that the bulk of the flux takes place between the 860 mb pressure surface and the surface of the earth. Between the 500 mb pressure surface and the upper limits of the Hadley and Ferrel cells the flux amounts to about 10 % of the total flux.
It is further shown that the Hadley cell circulation is the most important agent for transporting water vapour equatorward. North of 30°N the eddy flux is the dominant factor but appears to be of a much weaker intensity than the Hadley cell flux.
The computed values of the difference between the zonally averaged evaporation and precipitation (E - P) , for five-degree latitude belts, obtained in this study, show greater intensity in the equatorial belt than those obtained empirically by other authors (e.g. Jacobs). Palmen obtained a similar result some time ago.
Harmonic analyses show that in the equatorial belt proper, no definite wave number can be ascribed to the eddy vapour transport. In the subtropics, wave numbers one and two appear to be the active agents, whilst beyond 30°N wave numbers four and six take over.
A two-layer frictional model of wind-driven motion in a rectangular oceanic basin
Authors: Welander Pierre 
Published: January 2012

A study is made of the circulation in a two-layer ocean with rectangular boundaries driven by a zonal wind stress. The dynamics is linear, with bottom and interface stresses. A non-linearity arises from finite variations in layer depths. In the case where the lower layer is much deeper than the upper layer the equations can be integrated exactly. The solution gives a directly wind-driven gyre in the upper layer, with an interior Sverdrup regime and a western boundary current. In the lower layer there is no interior motion but a recirculating boundary current develops. The total transport is thereby intensified near the coast while a counter-transport develops at the outer edge. The boundary current width varies with the current depth and the latitude.The key parameter in the model is ε = (D/F)(H/h0), where D and F are the “frictional depths” applicable at the interface and the bottom, H and h0 are the total depth and the upper layer depth. Numerical examples are worked out for a sinusoidal wind stress distribution in the case ε = 1.
Atmospheric Effects on Cosmic Radiation, Air-mass Absorption and Meson
Decay
Authors: Lindholm F. 
Published: January 2012

The percentage variations of twenty-four hour means of C. R. in Stockholm (magn.
lat 58°) amount to ± 5% of the mean value over a quiet period of two months' duration.
The two atmospheric effects, the mass absorption due to ionisation and the meson decay,
contribute ± 4%. The residual variations, in excess of statistical fluctuations of 0.1%,
depend upon other factors, such as geomagnetic activity and solar influences. The
true absorption coefficient for zenith radiation (β) is calculated to have a value of
1.27 · 10–3 cm2/g and the rate of decay (β′) is found to be about 0.060 pr km. The meson
producing layer is attributed to the 200 mb surface, the highest level reached by the
daily radiosonde ascents in Stockholm. The most reliable decay value is obtained by
considerations of the thermal structure of air-mass changes in travelling deep
depressions.
Variation in the Earth’s Angular Velocity Resulting from Fluctuations in
Atmospheric and Oceanic Circulation
Authors: Munk W. H. , Miller R. L. 
Published: January 2012

Fluctuations in the circulation of the atmosphere are associated with very small
anomalies in the angular velocity of the earth. The seasonal component of these
anomalies has been computed from weather maps, and is found to agree, with respect to
magnitude and phase, with anomalies first reported by STOKYO in 1936 on the basis of
astronomic observations. The effects of fluctuations in the oceanic circulation, and of
shifting of air and water masses, have been estimated to account for not more than 15
per cent of the observed effect. The detection of shorter period fluctuations is
presently limited by the accuracy of astronomic time determination. The developments of
an atomic clock and of the photographic zenith tube open the possibility of determining
anomalies persisting for only two weeks, and of providing a new tool for obtaining an
index of integrated atmospheric circulation.
The Lowest of the Ionized Layers of the Upper Atmosphere
Authors: Stranz Dietrich 
Published: January 2012

The “Stockwerk-Gliederung” of the Earth’s atmosphere introduced by PENNDORF and
FLOHN is a promising method to describe the different atmospheric regions from the
nearest to the ground up to the highest levels. The region above the upper inversion (at
ca. 75 km) up to 100 km height is generally called the D-layer which means the lowest of
the ionized regions in the upper atmosphere of the Earth. The behaviour of the
D-layer, its most reasonable theory of formation, and its function with regard to the
propagation of electromagnetic waves are discussed. Features related to
solar-terrestrial phenomena are shown. Theories and ideas by various authors are
compared with each other. The complete investigation from which this paper gives an
extract is being published elsewhere.
Structure of Shear Lines near the Tropopause in Summer
Authors: Newton C. W. , Phillips N. A. , Carson J. E. , Bradbury D. L. 
Published: January 2012

A detailed study is made of a shear line in the tropopause region. A summer case was purposely selected, in which the lower half of the atmosphere was relatively barotropic, in order to minimize the role that could possibly be played by a subsiding cold air mass in producing a vertical stretching and consequent concentration of vorticity in the higher atmosphere.
During the period studied, the circulation over North America was characterized by the existence of two distinct jet streams, the southernmost of which, though initially having the form of a sinusoidal trough, appears to “buckle”, forming a very sharp trough separating two jet streams of opposite direction. A possible mechanism is suggested for the production of strong northerly flow leading up to shear-line formation, which depends upon a mutual interaction between the mass and velocity fields of the jet-stream systems located at different latitudes.
An attempt to determine whether potential absolute vorticity is conserved during formation of the shear line is not wholly conclusive, but indicates a reasonable possibility that vorticity may be generated in the free atmosphere.
Application of Barotropic Tendency Equation to Medium-Range Forecasting
Authors: Clapp Philip F. 
Published: January 2012

The simple barotropic vorticity equation has been used to compute height tendencies on a few 5-day mean 500 mb charts. The results are approximately as good as similar computations made on synoptic flow patterns despite the fact that the time interval between observed charts is 5 times as great. The order of magnitude of the computed tendencies may be considerably improved provided some account is taken of the effects of transformation of potential into kinetic energy, surface friction and non-adiabatic heating. A first approximation to these factors may be obtained by setting them equal to their climatological or normal values.
A simple method for integrating the barotropic equation is derived upon assuming that the anomalies of the large-scale flow patterns may be approximated by a relatively small number of Rankine vortices.
Some Aspects of the Flow of Stratified Fluids: II. Experiments with a Two-Fluid System
Authors: Long Robert R. 
Published: January 2012

A description is given of the flow of two superimposed layers of fluid over a barrier. This represents a partial experimental investigation of a problem considered theoretically in Part I.
In general three regimes of motion are possible: If the velocities of the fluids are sufficiently small the interface is little disturbed except for a slight depression over the barrier. If the velocities are sufficiently high the interface swells symmetrically over the obstacle. At intermediate speeds a hydraulic jump occurs in the lee of the barrier and the lower layer increases in depth upstream.
Two occurrences do not fit into the above description: If the obstacle is small compared to the depth of the lower layer, weak lee waves appear at low speeds, increasing in amplitude as the approach velocity of the fluid is increased. This seems to be the only case in which perturbation theory provides an adequate prediction of the flow. The second anomalous occurrence is the appearance of a “jump down” or hydraulic “drop” in the lee when the speed of the fluid is moderately high, the obstacle large, and the upper fluid relatively thin.
The description of the experiments is supplemented by a theoretical discussion, employing the assumption of a hydrostatic pressure distribution. In general this theory provides a satisfactory explanation of the observed behavior. The paper concludes with a discussion of meteorological implications.
Upper Mean Flow over the North Atlantic during January 1952
Authors: Hubert William , Dagel Yngve 
Published: January 2012

Three mean atmospheric cross sections, one along the eastern coast of North America near longitude 80° West, one extending from Hudson’s Bay out over the western Atlantic and the third along the western coasts of Europe and North Africa for January 1952 are presented. Four distinct currents are discussed in some detail; they are:

A polar stratospheric jet stream which is most clearly defined over Scandinavia where it shows up as a separate current centered near latitude 62° North. The maximum winds are above the 100-mb level.
A tropospheric jet stream in middle latitudes which weakens appreciably between the eastern coast of North America and western Europe but can be traced through all three cross sections (central potential temperature about 335° A).
A well-defined maximum over North Africa at latitude 24° North which has no clear connection with any maxima over North America and may form over the Atlantic Ocean. This current is centered at a potential temperature of approximately 345° A.
A mean low-latitude west-wind maximum over Panama at 45,000 feet near latitude 11° North. Mean observed wind profiles at Albrook Field, Panama and at Swan Island indicate that this really is a separate current and not the south edge of the middle-latitude jet stream. The central potential temperature in this maximum is about 355° A.
Wave Motion in a Rotating Couette Flow of a Viscous Fluid
Authors: Kao Shih-Kung 
Published: January 2012

With the assumption of non-divergence horizontal flow, a certain class of solutions of the nonlinear hydrodynamic equations are obtained for a viscous Couette flow on an earth whose variation of Coriolis parameter with latitude is constant. These solutions yield waves of transient type, of which the amplitude, wave velocity, and the inclination of the trough and ridge lines vary with time.
For Couette flow with both lateral and vertical velocity-shears, the vertical profile of the amplitude of the waves can either be exponential in z or independent of z, whereas for Couette flow with lateral velocity-shear only it permits to be independent of z, a sinusoidal function, or a hyperbolic sine or cosine of z. These waves will eventually disappear in a Couette flow regardless the fluid is viscous or not, although under certain conditions waves may be amplified within a certain time interval.
Pressure field, geostrophic deviation, meridional transports of energy and westerly momentum are obtained for such a flow system. For reasonable values of the constants for atmospheric systems, geostrophic deviation can be as high as one order magnitude smaller than the actual wind speed.
On the Maintenance of the Trade Winds
Authors: Malkus Joanne Starr 
Published: January 2012

A relation between the large-scale features of the lower trade stream and the effects of small-scale convective motions is investigated. The small-scale processes impose constraints upon the over-all circulation through non-adiabatic heating and the production of shearing stresses. These constraints may be formulated in terms of a theoretical model describing the mean flow in a section along the northern portion of the Pacific trade, which has previously been studied observationally in some detail.
In a simplified frictionless model with non-adiabatic heating the flow exhibits qualitatively many of the important features of the trades, such as subsidence, and a downstream acceleration, increased vertical wind shear, and pressure drop. The motion and pressure fields become numerically related to the heating as observed, however, only upon the introduction of frictional stresses. It is found possible to describe the frictional stress distribution in the lower trades without resorting to direct measurements, which thus provide a later independent check of the model.
The last sections of the paper consider possible quasi-steady rearrangements between the fields of motion, heating, and stress which might be regarded as steps in the slow fluctuations of the system about its average condition. This is done to inquire whether changes in any one of these properties will produce readjustments in the others acting to restore the mean or to accelerate the departure from it. Although such an analysis is handicapped by lack of knowledge concerning the interaction between the heating and stress distributions, one sample calculation suggests that a reduction of heating acts to relieve the subsidence and might thus be expected to restore the convection and thereby the heating. A stable coupling between small- and large-scale motions in the low-level trades is thus indicated, which may play a role in maintaining the high steadiness of the flow. The fact that the wind steadiness vanishes rapidly above the convective layer is clarified if this model is acceptable.
A Heuristic Theory of Large-Scale Turbulence and Long-Period Velocity Variations in Barotropic Flow
Authors: Thompson Philip Duncan 
Published: January 2012

By combining an equation for the conservation of zonal momentum with the eddy vorticity equation for nondivergent barotropic flow through a channel, it has been found possible to express the time variations of the longitude-averaged zonal wind in terms of the mean zonal wind itself and certain statistics of the eddy velocity field. In large-scale turbulence-where the characteristic dimension of the eddies is comparable with the entire “width” of the flow— these eddy statistics take on the properties of autocorrelation functions; thus, they depend primarily on the overall scale of the eddies and intensity of turbulence, rather than on details of the flow pattern. Changes in the scale and intensity of large-scale turbulence are related to changes in the mean zonal flow through the principles of conservation of total kinetic energy and variance of vorticity. Under a general hypothesis regarding the “stability” of the eddy statistics, the equations for the zonally-averaged motion comprise a complete system of nonlinear equations, which can be integrated by finite-sum and-difference methods. Accordingly, these equations constitute a mathematical theory of large-scale “free” turbulence, and provide the basis for a numerical method of predicting the zonally-averaged motion.
With the assumption that the eddy scale is invariant, the equation governing the mean zonal wind takes a form related to that of the classical wave equation. Numerical integrations of this equation verify that extremes of mean zonal wind (e.g., pronounced jets) maintain their identity over long periods of time, and migrate either northward or southward (or in both directions at once) in a very regular way—a phenomenon that has been observed by Riehl bt al. (1950). The results also show that a strong jet in the mean westerlies tends to split into two weaker jets, which then move in opposite directions to produce the separated double jet structure typical of widespread blocking. The latter has been described as a characteristic denouement from strong zonal flow by Cressman (1950). The theoretical speed of migration of extremes in the mean zonal wind is found to agree closely with the observed speed in a case where published data are available.
Since these features of long-period velocity variations—the most striking and regular discovered to date—have a characteristic time scale of a week or two, numerical prediction methods based on the present theory show some promise of aiding in the preparation of extendedrange forecasts.
Spectrum and Cross Spectrum Analysis of Hemispheric Westerly Index
Authors: Panofsky H. A. , Wolff P. 
Published: January 2012

The following tentative conclusions are drawn from the results of cross spectrum analysis applied to the hemispheric 500-mb zonal index at latitudes of 25° N, 40° N, and 60° N.
1. Most of the variations of the indices at 40° N and 60° N are produced by oscillations with periods of the order of 25 days. This result is obtained from two independent samples of data, each at least 2 1/2 years in length. At latitude 25° N, longer periods seem to be predominant. High-frequency fluctuations with periods of the order of five days may also be important, but have been filtered out by the analysis.
2. The indices at latitudes 60° N and 40° N are correlated negatively. Most of this correlation is again contributed by oscillations with a period of the order of 25 days. The correlation between latitudes 25° N and 40° N is also negative, but so small as to be hardly significant. Again, both sets of observations agree fairly well in furnishing these results.
3. There is an indication of a slight lag of the long-period variation of index at latitude 40° N behind that at 60° N.
Raindrop Measurements during Project Shower
Authors: Blanchard D. C. , Spencer A. T. 
Published: January 2012

Raindrop size distributions have been obtained on the island of Hawaii with filter papers and with a device called a drop recorder. The drop recorder automatically exposes a section of dyed paper tape to the rain at approximately two-minute intervals. The maximum sized drop found on each of the more than 4,000 samples has been plotted as a function of time. It is shown that a fair correlation exists between the maximum sized drop and rain intensity.
Over 300,000 drops m−3 < 0.2 mm diameter have been found in very light rains at altitudes of 5,500 feet on the volcanos of Mauna Kea and Mauna Loa.
The Global Architectural Influences on London
Authors: Fraser Murray 
Published: January 2012

AbstractLondon today has become ‘a laboratory and testing ground’ for neoliberal capitalism, attracting investment from the Middle East, Russia, India, the Far East and Australasia as well as the US. Murray Fraser describes the urban impact of economic globalisation in the capital, while exploring ways that it might potentially be countered. Copyright © 2012 John Wiley & Sons, Ltd.
Trompes L'Oeil
Authors: Devereux Mike 
Published: January 2012

AbstractMike Devereux sets out to explode the myth that London is an organic, unplanned city shaped by economic forces, and Paris is, in contrast, a planned city moulded by the state. He describes the many similarities that the two cities share and how planning ideas in fact ‘flowed between the capitals’ during the Haussmann era. Copyright © 2012 John Wiley & Sons, Ltd.