bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Moving Flame Experiment
Authors: Stern Melvin E. 
Published: January 2012

When a flame is rotated around the outside bottom rim of a cylindrical pan of water initially at rest, D. Fultz has observed that the fluid acquires a net vertical component of angular momentum opposite to the rotation of the heat source. We have repeated this experiment in a cylindrical annulus in order to restrict the radial motions and have found that the same phenomenon occurs. Using a simple model based on the latter experiment we investigate the mechanism by which a fluid can acquire and maintain this momentum, considering that friction is the only force which can exert a net torque about the vertical.
The effects of the heat source are replaced by a forced temperature field which has sinusoidal variations in the circumferential direction and which rotates about the vertical axis at a constant rate. The correlation between vertical and horizontal velocity components in the equilibrium state has been computed from the linearized two-dimensional vorticity equation. It is shown that when the viscosity is small or when the speed of the heat source is large there is a convergence of horizontal momentum towards the center of the channel which is balanced by the viscous stress of the induced mean motion. The total momentum of the fluid is computed from the conservation principle and is found to vary inversely as the square root of the molecular viscosity and inversely as the 5/2 power of the speed of the heat source.
An Advective Model of the Ocean Thermocline
Authors: Welander Pierre 
Published: January 2012

A theoretical study is made of the density field and the associated velocity field produced in an unlimited ocean by a prescribed density distribution at the surface. It is assumed that all motions take place under geostrophic and hydrostatic balance, and that the density is simply advected by the motions occurring. The computation is carried out for a spherical earth. The theory gives a depth of penetration of the surface disturbances of the order of 1000 m, if one assumes a relative density variation of the order 10−3 and a characteristic velocity below the boundary layer of the order 1 cm. sec−1. The depth of penetration is proportional to the sine of the latitude. Assuming a stable ocean with a surface density increasing from the equator to the pole the theory gives a meridional distribution of density of the form observed in the real oceans. The associated zonal velocities are westerlies at high latitudes, easterlies near the equator.
To permit a more precise check of the theory by laboratory experiments the corresponding solution is derived for a rotating “dishpan”. The solution is found to be of the same type as the one studied in the spherical case, but it is pointed out that fundamental differences between the spherical and parabolic cases are likely to occur in more general solutions than those studied here.
The Band Structure of the Atmosphere
Authors: Kuettner Joachim 
Published: January 2012

A general characteristic of the atmosphere is its streakiness. It manifests itself in many phenomena such as the “cloudstreets” of polar outbreaks and tradewinds, the radar bands of hurricanes and certain precipitation patterns, the squall lines and the jet stream cirrus.
The banded structure can be traced back to convection in heated air flows with a curved velocity profile of rather uniform direction. The typical vertical curvature was found to be 10−7 (cm−1 sec−1). A preliminary note deals with some theoretical considerations.
Synoptic cloud analysis by weather satellites will greatly profit from the wide spread existence of cloud bands.
On the Dynamics and Energy Transformations in Steady-State Hurricanes
Authors: Malkus J. S. , Riehl H. 
Published: January 2012

A dynamic model of the inflow layer in a steady mature hurricane is evolved, relating wind speed, pressure gradient, surface shearing stress, mass flow, and convergence. The low-level air trajectories are assumed to be logarithmic spirals. With this hypothesis, properties such as maximum wind and central pressure are determined through choice of a parameter depending on the inflow angle: a moderate hurricane arises with inflow angles of about 20°, while 25° gives an intense or extreme storm.
Most of this study treats the moderate storm. In order to maintain its core pressure gradients, an oceanic source of sensible and latent heat is required. As a result, latent heat release in the inner hurricane area occurs at higher heat content (warmer moist adiabats) than mean tropical subcloud air. The heat transfer from the ocean and the release of latent heat in the core determine the pressure gradient along the trajectory, and this prescribes the particular trajectory selected by the air among an infinite number available from the logarithmic spiral family.
This selection principle is evolved using recent work on “relative stability” of finite aniplitude thermal circulations. Of an infinite number of dynamically possible spirals, the one is realized which maximizes the rate of kinetic energy production under the thermodynamic constraints, here formulated in terms of the relation between heat release and pressure gradient.
Finally, rainfall, efficiency of work done by the storm, and kinetic energy budgets are examined in an attempt to understand the difference between the hurricane—a rare phenomenon—and the common sub-hurricane tropical storm.
Further Examples of Stationary Planetary Flow Patterns in Bounded Basins
Authors: Faller Alan J. 
Published: January 2012

Laboratory experiments which supplement those presented by STOMMEL, ARONS and FALLER (1958) are described. Extension of the analysis to include the effects of bottom friction shows that the characteristic spreading of zonal currents, apparent in the original experiments, is due to bottom friction combined with the radial depth variation. The experiments confirm the theoretical prediction of an intense “recirculation” from the western boundary (similar to the “wind-spun vortex” of MUNK, 1950) when a localized interior source or sink is present. Application of the basic concepts of the earlier paper to the geometrically more complicated case with a partial radial barrier gave good agreement between theory and experiment, but the limiting effects of bottom friction were made evident in other examples.
An eastern boundary current was found to occur in a situation geometrically similar to the intrusion of Mediterranean water into the Atlantic Ocean. Simple transformations illustrate the application of the equations developed in polar coordinates to the flow of a uniform fluid on a sphere, and examples of “recirculation” and the spread of zonal flow are worked out for a barotropic ocean of uniform depth.
Radiocarbon Concentration in Pacific Ocean Water
Authors: Bien G. S. , Rakestraw N. W. , Suess H. E. 
Published: January 2012

Results of C14 determinations in surface water from the Pacific were in agreement with those reported by Rafter and Fergusson. However, abnormal C14 concentrations seem to exist locally, for which no oceanographic explanation can be given. It seems premature to draw conclusions from existing determinations as to the rate of increase of C14 in surface ocean water resulting from the uptake of C14 produced in the atmosphere by atomic bombs.
Samples from a constant depth of about 3,500 meters show a C14 content decreasing from south to north. This decrease may be attributed to radioactive decay of C14 during the time of migration. From this the northward component of the rate of water movement of about 0.06 cm/sec can be calculated. The C13 determinations, for the purpose of correcting the C14 values for isotope fractionation effects. were found to be remarkably consistent, although made on reburned acetylene.
On the Distribution of Temperature Relative to Height in Stationary Planetary Wave?
Authors: Wiin-Nielsen A. 
Published: January 2012

It is shown that some gross features of the distribution of the mean temperature relative to the mean height on the normal maps for January can be computed from the vertically integrated linearized vorticity equation, if the effects of surface friction and mountains are included in the equation for the stationary case. By a mathematical analysis supplemented by certain numerical experiments it is shown that it is necessary to assume a meridional scale parameter corresponding to less than 90 degrees of latitude in order to obtain the correct phase-lag. An empirical determination of the meridional wave-length was carried out using 500 mb data for a single month (January 1959).
Section 6 contains some comments on the assumptions made in this study. It is especially pointed out that the effect of horizontal advection of vorticity and the effects of the lower boundary condition (friction and topography) cannot be neglected in comparison with the beta-effect in studies of stationary motion on the planetary scale.
Height, structure and displacements of noctilucent clouds
Authors: Witt Georg 
Published: January 2012

Observations of noctilucent clouds have been carried out during the summer of 1968 at Torsta (63.3° N ; 14.6° E) in Central Sweden as part of the IGY working program of the Institute of Meteorology, University of Stockholm. Simultaneous pairs of cloud photographs have been taken with accurate phototheodolite cameras from the endpoints of a geodetically determined base-line of length 51.6 km. The picture pairs were subsequently analyzed in stereo instruments (autograph) by which Cartesian space coordinates were obtained for various points in the cloud system. These coordinates, duly corrected for atmospheric refraction, were used for determination of the height of the individual features. Through the stereoscopic effect, measurements could be made on diffuse parts of the cloud system as well as on marked details. Additional information about movements of the cloud system was obtained from a time-lapse film in Kodachrome. The results were plotted and analyzed by conventional methods and maps of the cloud topography at consecutive time intervals could be prepared. In addition to these maps, vertical cross-sections through the cloud system were made as well as detailed studies of particularly interesting cloud features. This paper gives a presentation and interpretation of the results obtained so far and a brief description of the photogrammetric technique applied.
The results presented below were obtained during a very bright cloud display with good visibility conditions on August 10-11th, 1958. Thirty pairs of pictures were taken of various parts of the cloud system, which covered the entire northern horizon. Eight of these have been analyzed 80 far. The results can be summarized as follows. The cloud system moved in a direction north-east to south-west with velocities of the order of 50 to 100 m/s. It consisted of a continuous diffuse layer interchanging with regions of sharply defined features such as systems of parallel billows and bands, blobs and other smaller-scale irregularities of various shapes. The measured heights varied between 81.6 and 86.6 km. The long parallel bands were identified as a system of waves with wavelengths of the order of 60 km and amplitudes up to 4 km which propagated in a direction nearly opposite to that of the cloud system with absolute velocities of the order of 10 to 20 m/s. The wave crests were oriented nearly perpendicular to the main air flow and were continuous over distances of hundreds of kilometers and exhibited local refraction effects. The smaller billows had wavelengths of the order of 6-10 km and amplitudes about 0.5-1.0 km; they moved with the cloud sysem. The billows showed no preferred orientation and were observed to pass through the crests of the longer waves. It is indicated by the analysis the regular changes in the brightness of these clouds are due to changes of the optical thickness of the cloud layer, particularly at the rear slope of the long waves. The measured details had well-defined lower boundaries.
Further aspects on the diurnal temperature variation at the surface of the earth
Authors: Lonnqvist Olov 
Published: January 2012

From a number of independent clear-sky observations of global radiation and temperature at the surface of the earth, typical values are derived for the diurnal variation of these elements for certain specified lengths of the day. An attempt is made to relate the typical variation of radiation with that of surface temperature by the aid of a formula recently suggested by the author. The agreement is good and the constants used in the formula resemble those previously used by the author.
Depending on the actual conditions (type of soil, humidity gradient in the air, etc.) various combinations of the two constants should be used in the formula. It is demonstrated how the choice of constants affects the amplitude and phase lag of the temperature curve. Also discussed is the possibility of incorporating turbulence effects in the formula.
Topographic Influences on the Path of the Gulf Stream
Authors: Warren Bruce A. 
Published: January 2012

Meander patterns observed in the Gulf Stream east of Cape Hatteras exhibit correlations with bottom topography. An examination of the orders of magnitude of terms in the Gulf Stream vorticity balance suggests that if the current extends to the ocean bottom, as implied by some recent deep velocity measurements, its path must indeed be controlled principally by the topography of the Continental Rise, with a generally smaller constraint imposed by the meridional variation of the Coriolis parameter. Approximate current paths calculated according to this mechanism-steady-state conservation of potential vorticity-agree sufficiently well with observed paths to confirm the topographic explanation of large-scale meanders.
The observed variety in meander patterns is attributed to fluctuations in current direction and path curvature near Cape Hatteras.
These conclusions make doubtful any direct relation between large-scale meanders and possible instabilities of the Gulf Stream east of Cape Hatteras, and between the distribution of wind stress and the separation of Stream from coast.
Stratospheric ice nucleus measurements from balloons
Authors: Bigg E. K. , Miles G. T. 
Published: January 2012

The ice nucleus content of stratospheric air was measured at one height in the range 13 to 27 km, on each of 13 experiments, by means of a vacuum pump and filters carried on large balloons.
The concentrations were in close agreement with those found by TELFORD (1960) using an expansion cold chamber in an aeroplane and, per unit mass of air, were comparable with the extreme maxima recorded at the ground in long sequences of measurements in Australia. It is suggested that localised rapid transfer of air from stratosphere to lower troposphere is a probable cause of some ice nucleus storms at the ground. The source of the stratospheric ice nuclei is uncertain but reasons are given for supposing the nuclei to be of extra-terrestrial origin.
An experimental study on atmospheric diffusion
Authors: Högström Ulp 
Published: January 2012

A method has been devised by which atmospheric diffusion can be studied over a few kilometres range with rather good precision at only moderate expense. The method which is based on smoke puff photography is especially well suited for thermally stable conditions. It is possible to study the effect of both the low frequency part and the high frequency part of the Lagrangian spectrum of turbulence on the diffusion. More than 100 complete experiments have been performed at two places in Sweden at three different levels of release.The vertical standard deviation of matter is found to be a function of the following stability parameter: (∂θ/∂z)/u2f, where ∂θ/∂z is the local vertical gradient of potential temperature, and uzf is “the free wind”, that is the wind just above the friction layer. A comprehensive formula, or rather a system of formulae, for the variation of the vertical standard deviation (sampling time about one hour) with distance from the source, stability and height above the ground of the point of release, has been developed. The formulae are believed to have a very general application, the only site parameter being necessary to know is the roughness length, z0. The formulae have been successfully tested against results from various tracer experiments described in the literature.The variance of the horizontal distribution of matter for one hour sampling time is found to be the sum of two parts: one which is independent of stability and one which is dependent on stability in much the same way as is the vertical variance.The distribution of matter from a ground level release is described by new formulae. The result is in good agreement with experimental and theoretical evidence in the literature.
The viscous boundary layer at the free surface of a rotating baroclinic fluid: effects due to the temperature dependence of surface tension
Authors: Hide R. 
Published: January 2012

A theoretical study is made of the effects due to the dependence on temperature (T) of the coefficient of surface tension (S) on the flow in the viscous boundary layer at the free surface of a baroclinic fluid which rotates rapidly about a vertical axis. Although each component of the flow is altered by an amount of the order of the corresponding ageostrophic component arising when dS/dT = 0 multiplied by the dimension-less parameter C ≡ 2 Ω. (dS/dT)/(gαᵨ0v) (where Ω is the rate of rotation of the system, g the acceleration of gravity, and ᵨ0, v and α denote, respectively, the mean density, kinematic viscosity and thermal coefficient of cubical expansion of the fluid), when the interior flow is strictly geostrophic boundary layer suction remains unaffected.
On the Vertical Distribution of Wind and Temperature over Indo-Pakistan along the
Meridian 76° E in Winter
Authors: Chaudhury A. M. 
Published: January 2012

A mean cross-section over Indo-Pakistan along the meridian 76° E for January and
February 1946 has been computed. Three jet stream centers are obtained along this
meridian: one in Siberia, one just south of the plateau, and one in the tropics. The
effect of the plateau gives rise to Siberian and Himalayan jets. A numerical comparison
of the computed mean profile along 76° E with that of HESS (1948) along 80° W over North
America is presented. Computed wind velocity, wind shear and absolute vorticity
patterns are discussed, particularly with regard to strong anticyclonic shear and very
low absolute vorticity found on the south side of the Himalayan jet. The spatial
distributions of the isentropic field, the gravitational stability field, the
baroclinity field and the rainfall during the winter months are discussed in regard to
the sense of the meridional circulation around the Himalayan and the Equatorial
jets.
A Synoptic-Aerological Study of Interaction between Vortices
Authors: Berson F. A. 
Published: January 2012

The displacement and intensity changes of a cyclone and anticyclone over the Northeastern Atlantic in October 1945 are investigated. An attempt is made to explain the motion of the cells as an analogue to the vortex pair in hydrodynamics. The observed paths and translational velocities are compared with those computed from theoretical relationships derived on simplifying assumptions involving a.o. conservation of absolute vorticity and an hypothesis of equivalent vortex strength. With reference to the third day after the genesis of the system, the result of this comparison is satisfactory and is considered significant in view of a concurrent transient reduction of horizontal divergence inferred from observed variations in the thermal structure of the cyclone.
The genesis and behaviour of the system of vortices is also discussed in relation to a recent theory of composite baroclinic vortices. In part this theory is confirmed by observational evidence as e.g. an accelerated equatorward drift of the cyclone in its early stage and an intensification of its upper part in a later stage when the centre of the system of vortices is stationary.
The Distribution of Temperature and Wind Connected with Active Tropical Air in the Higher Troposphere and Some Remarks Concerning Clear Air Turbulence at High Altitude
Authors: Berggren Roy 
Published: January 2012

A study is made of the distribution of wind and temperature in the higher troposphere and the lower stratosphere in cases with active Tropical air in middle latitudes. Only observed winds are used. A model for extending the fronts into the lower stratosphere is given.
In connection with the proposed model a case with observed clear air turbulence at high altitude is studied. Some remarks on the statistical treatment of the reported cases with clear air turbulence is made.
A Baroclinic Model of the Atmosphere Applicable to the Problem of Numerical Forecasting in Three Dimensions. II
Authors: Árnason G. 
Published: January 2012

A theory for the application to numerical forecasting of a 3-parameter model of the troposphere is developed and then tested on one synoptic case. The model itself has been described in an earlier paper. An essential feature of this model, beyond other models so far introduced, is that the static stability may vary arbitrarily in a horizontal direction and with time as well. This implies a thermal wind which may change direction with height, and it is shown that this non-parallelism of the isotherms in the vertical is important from the standpoint of thermodynamics. Furthermore, it is shown that the rotation of the thermal wind with height is closely connected with cyclogenesis and the deepening and filling of existing cyclones.
The case selected for numerical computation was the synoptic situation of November 24, 1951, at 03z over Western Europe and the easternmost part of the Atlantic. Tendencies for sea level pressure and for the two parameters defining the tropospheric temperature distribution with height were computed; they compared fairly well with observed changes.
The Threefold Structure of the Atmosphere and the Characteristics of the Tropopause
Authors: Defant Fr. , Taba H. 
Published: January 2012

All available soundings for January 1, 1956 have been studied with respect to their tropospheric and stratospheric temperature structure and with emphasis on the height and form of the tropopause. It was found that the latitudinal influence on the total vertical structure of the soundings was not dominating, but rather the location of soundings with respect to the two main westwind maxima (polarfront jet and subtropical jet) of the westerlies seemed to be important. A selection of soundings according to this principle (north of polarfront jet, between the two jets, south of subtropical jet) made it possible to distinguish between different types of soundings. This fundamental difference is discussed and will form the basis for future studies of world wide circulation changes. Furthermore the distribution of tropopause height and temperature has been mapped and studied on a hemispheric scale. Each of the above mentioned types possesses a typical vertical temperature structure and a characteristic tropopause heigth. Two rapid changes in tropopause height (tropopause breaklines) connected with the main westwind belts separate areas possessing an almost uniform tropopause level. Inside each of these areas a remarkable quasi-barotropic state of the upper tropospheric layers is shown.
Similar discussion has been devoted to the nature of soundings inside or close to the jets or the breaks in tropopause height. Here the soundings have a more complicated vertical structure and their interpretation becomes difficult.